man
1 mail
S-NAIL(1) BSD General Commands Manual S-NAIL(1)
NAME
S-nail [v14.9.22] -- send and receive Internet mail
SYNOPSIS
s-nail [-DdEFinv~#] [-: spec] [-A account] [:-a attachment:]
[:-b bcc-addr:] [:-C "field: body":] [:-c cc-addr:]
[-M type | -m file | -q file | -t] [-r from-addr]
[:-S var[=value]:] [-s subject] [:-T "field: addr":] [:-X cmd:]
[:-Y cmd:] [-.] :to-addr: [-- :mta-option:]
s-nail [-DdEeHiNnRv~#] [-: spec] [-A account] [:-C "field: body":]
[-L spec] [-r from-addr] [:-S var[=value]:] [-u user] [:-X cmd:]
[:-Y cmd:] [-- :mta-option:]
s-nail [-DdEeHiNnRv~#] [-: spec] [-A account] [:-C "field: body":] -f
[-L spec] [-r from-addr] [:-S var[=value]:] [:-X cmd:] [:-Y cmd:]
[file] [-- :mta-option:]
s-nail -h | --help
s-nail -V | --version
DESCRIPTION
Note: S-nail (S-nail) will see major changes in v15.0 (circa 2022).
Some backward incompatibilities cannot be avoided. COMMANDS change
to Shell-style argument quoting, and shell metacharacters will be-
come (more) meaningful. Some commands accept new syntax today via
wysh (Command modifiers). Behaviour is flagged [v15-compat] and
[no v15-compat], setting v15-compat (INTERNAL VARIABLES) will
choose new behaviour when applicable; giving it a value makes wysh
an implied default. [Obsolete] flags what will vanish.
Warning! v15-compat (with value) will be a default in v14.10.0!
S-nail provides a simple and friendly environment for sending and receiv-
ing mail. It is intended to provide the functionality of the POSIX
mailx(1) command, but is MIME capable and optionally offers extensions
for line editing, S/MIME, SMTP and POP3, among others. S-nail divides
incoming mail into its constituent messages and allows the user to deal
with them in any order. It offers many COMMANDS and INTERNAL VARIABLES
for manipulating messages and sending mail. It provides the user simple
editing capabilities to ease the composition of outgoing messages, and
increasingly powerful and reliable non-interactive scripting capabili-
ties.
Options
-: spec, --resource-files=..
Controls loading of (as via source) Resource files: spec is
parsed case-insensitively, the letter `s' corresponds to the
system wide s-nail.rc, `u' the user's personal file ~/.mailrc.
The (original) system wide resource is also compiled-in, acces-
sible via `x'. The letters `-' and `/' disable usage of re-
source files. Order matters, default is `su'. This option
overrides -n.
-A name, --account=..
Activate user account name after program startup is complete
(resource files loaded, only -X commands are to be executed),
and switch to its primary system mailbox (most likely the
inbox). If activation fails the program exits if used non-in-
teractively, or if any of errexit or posix are set.
-a file[=input-charset[#output-charset]], --attach=..
(Send mode) Attach file. For (Compose mode) opportunities re-
fer to ~@ and ~^. file is subject to tilde expansion (see
Filename transformations and folder); if it is not accessible
but contains a `=' character, anything before the last `=' will
be used as the filename, anything thereafter as a character set
specification, as shown.
If only an input character set is specified, the input side is
fixed, and no character set conversion will be applied; an
empty or the special string hyphen-minus `-' is taken for
ttycharset (the default). If an output character set has also
been specified the desired conversion is performed immediately,
not considering file type and content, except for an empty
string or hyphen-minus `-', which select the default conversion
algorithm (see Character sets): no immediate conversion is per-
formed, file and its contents will be MIME-classified (HTML
mail and MIME attachments, The mime.types files) first -- only
the latter mode is available unless features includes
`,+iconv,'.
-B ([Obsolete]: S-nail will always use line-buffered output, to
gain line-buffered input even in batch mode enable batch mode
via -#.)
-b addr, --bcc=..
(Send mode) Send a blind carbon copy to recipient addr. The
option may be used multiple times. Also see the section On
sending mail, and non-interactive mode.
-C "field: body", --custom-header=..
Create a custom header which persists for an entire session. A
custom header consists of the field name followed by a colon
`:' and the field content body, for example `-C "Blah: Neminem
laede; imo omnes, quantum potes, juva"'. Standard header field
names cannot be overwritten by custom headers. Runtime ad-
justable custom headers are available via the variable
customhdr, and in (Compose mode) ~^, one of the COMMAND
ESCAPES, as well as digmsg are the most flexible and powerful
options to manage message headers. This option may be used
multiple times.
-c addr, --cc=..
(Send mode) Just like -b, except it places the argument in the
list of carbon copies.
-D, --disconnected
[Option] Startup with disconnected set.
-d, --debug
Enter a debug-only sandbox mode by setting the internal vari-
able debug; the same can be achieved via `-S debug' or `set
debug'. Also see -v.
-E, --discard-empty-messages
(Send mode) set skipemptybody and thus discard messages with an
empty message part body, successfully.
-e, --check-and-exit
Just check if mail is present (in the system inbox or the one
specified via -f): if yes, return an exit status of zero, a
non-zero value otherwise. To restrict the set of mails to con-
sider in this evaluation a message specification can be added
with the option -L. Quickrun: does not open an interactive
session.
-F (Send mode) Save the message to send in a file named after the
local part of the first recipient's address (instead of in
record).
-f, --file
Read in the contents of the user's secondary mailbox MBOX (or
the specified file) for processing; when S-nail is quit, it
writes undeleted messages back to this file (but be aware of
the hold option). The optional file argument will undergo some
special Filename transformations (as via folder). Note that
file is not an argument to the flag -f, but is instead taken
from the command line after option processing has been com-
pleted. In order to use a file that starts with a hyphen-mi-
nus, prefix with a relative path, as in `./-hyphenbox.mbox'.
-H, --header-summary
Display a summary of headers for the given folder (depending on
-u, inbox or MAIL, or as specified via -f), then exit. A con-
figurable summary view is available via the option -L. This
mode does not honour showlast. Quickrun: does not open an in-
teractive session.
-h, --help
Show a brief usage summary; use --long-help for a list long op-
tions.
-i set ignore to ignore tty interrupt signals.
-L spec, --search=..
Display a summary of headers of all messages that match the
given spec in the folder found by the same algorithm used by
-H, then exit. See the section Specifying messages for the
format of spec. This mode does not honour showlast.
If the -e option has been given in addition no header summary
is produced, but S-nail will instead indicate via its exit sta-
tus whether spec matched any messages (`0') or not (`1'); note
that any verbose output is suppressed in this mode and must in-
stead be enabled explicitly (see -v). Quickrun: does not open
an interactive session.
-M type (Send mode) Will flag standard input with the MIME
`Content-Type:' set to the given known type (HTML mail and MIME
attachments, The mime.types files) and use it as the main mes-
sage body. [v15 behaviour may differ] Using this option will
bypass processing of message-inject-head and
message-inject-tail. Also see -q, -m, -t.
-m file (Send mode) MIME classify the specified file and use it as the
main message body. [v15 behaviour may differ] Using this op-
tion will bypass processing of message-inject-head and
message-inject-tail. Also see -q, -M, -t.
-N, --no-header-summary
inhibit the initial display of message headers when reading
mail or editing a mailbox folder by calling unset for the in-
ternal variable header.
-n Standard flag that inhibits reading the system wide s-nail.rc
upon startup. The option -: allows more control over the
startup sequence; also see Resource files.
-q file, --quote-file=..
(Send mode) Initialize the message body with the contents of
file, which may be standard input `-' only in non-interactive
context. Also see -M, -m, -t.
-R, --read-only
Any mailbox folder aka folder opened will be in read-only mode.
-r from-addr, --from-address=..
The RFC 5321 reverse-path used for relaying and delegating mes-
sages to its destination(s), for example to report delivery er-
rors, is normally derived from the address which appears in the
from header (or, if that contains multiple addresses, in
sender). A file-based aka local executable mta (Mail-Transfer-
Agent), however, instead uses the local identity of the initi-
ating user.
When this command line option is used the given single ad-
dressee from-addr will be assigned to the internal variable
from, but in addition the command line option -f from-addr will
be passed to a file-based mta whenever a message is sent.
Shall from-addr include a user name the address components will
be separated and the name part will be passed to a file-based
mta individually via -F name. Even though not a recipient the
`shquote' expandaddr flag is supported.
If an empty string is passed as from-addr then the content of
the variable from (or, if that contains multiple addresses,
sender) will be evaluated and used for this purpose whenever
the file-based mta is contacted. By default, without -r that
is, neither -f nor -F command line options are used when con-
tacting a file-based MTA, unless this automatic deduction is
enforced by setting the internal variable r-option-implicit.
Remarks: many default installations and sites disallow overrid-
ing the local user identity like this unless either the MTA has
been configured accordingly or the user is member of a group
with special privileges. Passing an invalid address will cause
an error.
-S var[=value], --set=..
set (or, with a prefix string `no', as documented in INTERNAL
VARIABLES, unset) variable and optionally assign value, if sup-
ported; [v15 behaviour may differ] the entire expression is
evaluated as if specified within dollar-single-quotes (see
Shell-style argument quoting) if the internal variable
v15-compat is set. If the operation fails the program will
exit if any of errexit or posix are set. Settings established
via -S cannot be changed from within Resource files or an ac-
count switch initiated by -A. They will become mutable again
before commands registered via -X are executed.
-s subject, --subject=..
(Send mode) Specify the subject of the message to be sent.
Newline (NL) and carriage-return (CR) bytes are invalid and
will be normalized to space (SP) characters.
-T "field: addr", --target=..
(Send mode) Add addr to the list of receivers targeted by
field, for now supported are only `bcc', `cc', `fcc', and `to'.
Field and body (address) are separated by a colon `:' and op-
tionally blank (space, tabulator) characters. The `shquote'
expandaddr flag is supported. addr is parsed like a message
header address line, as if it would be part of a template mes-
sage fed in via -t, and the same modifier suffix is supported.
This option may be used multiple times.
-t, --template
(Send mode) The text message given (on standard input) is ex-
pected to contain, separated from the message body by an empty
line, one or multiple plain text message headers. [v15 behav-
iour may differ] Readily prepared MIME mail messages cannot be
passed. Headers can span multiple consecutive lines if follow
lines start with any amount of whitespace. A line starting
with the number sign `#' in the first column is ignored. Mes-
sage recipients can be given via the message headers `To:',
`Cc:', `Bcc:' (the `?single' modifier enforces treatment as a
single addressee, for example `To?single: exa, <m@ple>') or
`Fcc:', they will be added to any recipients specified on the
command line, and are likewise subject to expandaddr validity
checks. If a message subject is specified via `Subject:' then
it will be used in favour of one given on the command line.
More optional headers are `Reply-To:' (possibly overriding
reply-to), `Sender:' (sender), `From:' (from and / or option
-r). `Message-ID:', `In-Reply-To:', `References:' and
`Mail-Followup-To:', by default created automatically dependent
on message context, will be used if specified (a special ad-
dress massage will however still occur for the latter). Any
other custom header field (also see -C, customhdr and ~^) is
passed through entirely unchanged, and in conjunction with the
options -~ or -# it is possible to embed COMMAND ESCAPES. Also
see -M, -m, -q.
-u user, --inbox-of=..
Initially read the primary system mailbox of user, appropriate
privileges presumed; effectively identical to `-f %user'.
-V, --version
Show S-nails version and exit. The command version will also
show the list of features: `$ s-nail -:/ -Xversion -Xx'.
-v, --verbose
sets the internal variable verbose to enable logging of infor-
mational context messages. (Increases level of verbosity when
used multiple times.) Also see -d.
-X cmd, --startup-cmd=..
Add the given (or multiple for a multiline argument) cmd to a
list of commands to be executed before normal operation starts.
The commands will be evaluated as a unit, just as via source.
Correlates with -# and errexit.
-Y cmd, --cmd=..
Add the given (or multiple for a multiline argument) cmd to a
list of commands to be executed after normal operation has
started. The commands will be evaluated successively in the
given order, and as if given on the program's standard input --
before interactive prompting begins in interactive mode, after
standard input has been consumed otherwise.
-~, --enable-cmd-escapes
Enable COMMAND ESCAPES in (Compose mode) even in non-interac-
tive use cases. This can for example be used to automatically
format the composed message text before sending the message:
$ ( echo 'line one. Word. Word2.';\
echo '~| /usr/bin/fmt -tuw66' ) |\
LC_ALL=C s-nail -d~:/ -Sttycharset=utf-8 bob@exam.ple
-#, --batch-mode
Enables batch mode: standard input is made line buffered, the
complete set of (interactive) commands is available, processing
of COMMAND ESCAPES is enabled in Compose mode, and diverse
INTERNAL VARIABLES are adjusted for batch necessities, exactly
as if done via -S: emptystart, noerrexit, noheader, noposix,
quiet, sendwait, typescript-mode as well as MAIL, MBOX and
inbox (the latter three to /dev/null). Also, the values of
COLUMNS and LINES are looked up, and acted upon. The following
prepares an email message in a batched dry run:
$ for name in bob alice@exam.ple lisa@exam.ple; do
printf 'mail %s\n~s ubject\nText\n~.\n' "${name}"
done |
LC_ALL=C s-nail -#:x -Smta=test \
-X'alias bob bob@exam.ple'
-., --end-options
This flag forces termination of option processing in order to
prevent "option injection" (attacks). It also forcefully puts
S-nail into send mode, see On sending mail, and non-interactive
mode.
If the setting of expandargv allows their recognition all mta-option ar-
guments given at the end of the command line after a `--' separator will
be passed through to a file-based mta (Mail-Transfer-Agent) and persist
for the entire session. expandargv constraints do not apply to the con-
tent of mta-arguments. Command line receiver address handling supports
the `shquote' constraint of expandaddr, for more please see On sending
mail, and non-interactive mode.
$ s-nail -#:/ -X 'addrcodec enc Hey, ho <silver@go>' -Xx
A starter
S-nail is a direct descendant of BSD Mail, itself a successor to the Re-
search UNIX mail which "was there from the start" according to HISTORY.
It thus represents the user side of the UNIX mail system, whereas the
system side (Mail-Transfer-Agent, MTA) was traditionally taken by
sendmail(8) (and most MTAs provide a binary of this name for compatibil-
ity reasons). If the [Option]al SMTP mta is included in the features of
S-nail then the system side is not a mandatory precondition for mail de-
livery.
S-nail strives for compliance with the POSIX mailx(1) standard, but
posix, one of the INTERNAL VARIABLES, or its ENVIRONMENTal equivalent
POSIXLY_CORRECT, needs to be set to adjust behaviour to be almost on par.
Almost, because there is one important difference: POSIX Shell-style
argument quoting is ([v15 behaviour may differ] increasingly) used in-
stead of the Old-style argument quoting that the standard documents,
which is believed to be a feature. The builtin as well as the (default)
global s-nail.rc Resource files already bend the standard imposed set-
tings a bit.
For example, hold and keepsave are set in order to suppress the automatic
moving of messages to the secondary mailbox MBOX that would otherwise oc-
cur (see Message states), and keep to not remove empty system MBOX mail-
box files (or all empty such files in posix mode) to avoid mangling of
file permissions when files eventually get recreated.
To enter interactive mode even if the initial mailbox is empty emptystart
is set, editheaders to allow editing of headers as well as fullnames to
not strip down addresses in Compose mode, and quote to include the mes-
sage that is being responded to when replying, which is indented by an
indentprefix that also deviates from standard imposed settings.
mime-counter-evidence is fully enabled, too. It sets followup-to-honour
and reply-to-honour to comply with reply address desires.
Credentials and other settings are easily addressable by grouping them
via account. The file mode creation mask can be managed with umask.
Files and shell pipe output can be sourced for evaluation, also during
startup from within the Resource files. Informational context can be
available by setting verbose or debug (as via -v, -d).
On sending mail, and non-interactive mode
To send a message to one or more people, using a local or built-in mta
(Mail-Transfer-Agent) transport to actually deliver the generated mail
message, S-nail can be invoked with arguments which are the names of peo-
ple to whom the mail will be sent, and the command line options -b and -c
can be used to add (blind) carbon copy receivers:
# Via test MTA
$ echo Hello, world | s-nail -:/ -Smta=test -s test $LOGNAME
# Via sendmail(1) MTA
$ </dev/null s-nail -:x -s test $LOGNAME
# Debug dry-run mode:
$ </dev/null LC_ALL=C s-nail -d -:/ \
-Sttycharset=utf8 -Sfullnames \
-b bcc@exam.ple -c cc@exam.ple -. \
'(Lovely) Bob <bob@exam.ple>' eric@exam.ple
# With SMTP (no real sending due to -d debug dry-run)
$ LC_ALL=C s-nail -d -:/ -Sv15-compat -Sttycharset=utf8 \
-S mta=smtps://mylogin@exam.ple:465 -Ssmtp-auth=none \
-S from=scriptreply@exam.ple \
-a /etc/mail.rc --end-options \
eric@exam.ple < /tmp/letter.txt
Email addresses and plain user names are subject to alternates filtering,
names only are first expanded through alias and mta-aliases. An address
in angle brackets consisting only of a valid local user `<name>' will be
converted to a fully qualified address if either hostname is not set, or
set to a non-empty value; if set to the empty value the conversion is
left up to the mta. By setting expandaddr fine-grained control of recip-
ient address types other than user names and network addresses is possi-
ble. Recipients are classified as follows: any name that starts with a
vertical bar `|' character specifies a command pipe - the command string
following the `|' is executed and the message is sent to its standard in-
put; likewise, any name that consists only of hyphen-minus `-' or starts
with the character solidus `/' or the character sequence dot solidus `./'
is treated as a file, regardless of the remaining content. Any other
name which contains a commercial at `@' character is a network address;
Any other name which starts with a plus sign `+' character is a mailbox
name; Any other name which contains a solidus `/' character but no excla-
mation mark `!' or percent sign `%' character before is also a mailbox
name; What remains is treated as a network address. This classification
can be avoided by using a `Fcc:' header, see Compose mode.
$ echo bla | s-nail -Sexpandaddr -s test ./mbox.mbox
$ echo bla | s-nail -Sexpandaddr -s test '|cat >> ./mbox.mbox'
$ echo safe | LC_ALL=C \
s-nail -:/ -Smta=test -Sv15-compat -Sttycharset=utf8 \
--set mime-force-sendout --set fullnames \
-S expandaddr=fail,-all,+addr,failinvaddr -s test \
--end-options 'Imagine John <cold@turk.ey>'
Before messages are sent they undergo editing in Compose mode. But many
settings are static and can be set more generally. The envelope sender
address for example is defined by from, explicitly defining an originat-
ing hostname may be desirable, especially with the built-in SMTP Mail-
Transfer-Agent mta. Character sets for outgoing message and MIME part
content are configurable via sendcharsets, whereas input data is assumed
to be in ttycharset. Message data will be passed over the wire in a
mime-encoding, and MIME parts aka attachments need a mimetype, usually
taken out of The mime.types files. Saving copies of sent messages in a
record mailbox may be desirable - as for most mailbox folder targets
Filename transformations will be performed.
For the purpose of arranging a complete environment of settings that can
be switched to with a single command or command line option there are
accounts. Alternatively a flat configuration could be possible, making
use of so-called variable chains which automatically pick `USER@HOST' or
`HOST' context-dependent variants some variables support: for example ad-
dressing `Folder pop3://yaa@exam.ple' would find
pop3-no-apop-yaa@exam.ple, pop3-no-apop-exam.ple and pop3-no-apop in or-
der. For more please see On URL syntax and credential lookup and
INTERNAL VARIABLES.
To avoid environmental noise scripts should create a script-local envi-
ronment, ideally with the command line options -: to disable configura-
tion files in conjunction with repetitions of -S to specify variables:
$ env LC_ALL=C s-nail -:/ \
-Sv15-compat \
-Sttycharset=utf-8 -Smime-force-sendout \
-Sexpandaddr=fail,-all,failinvaddr \
-S mta=smtps://mylogin@exam.ple:465 -Ssmtp-auth=login \
-S from=scriptreply@exam.ple \
-s 'Subject to go' -a attachment_file \
-Sfullnames -. \
'Recipient 1 <rec1@exam.ple>' rec2@exam.ple \
< content_file
As shown, scripts can "fake" a locale environment, the above specifies
the all-compatible 7-bit clean LC_ALL "C", but will nonetheless take and
send UTF-8 in the message text by using ttycharset. If character set
conversion is compiled in (features includes the term `,+iconv,') invalid
(according to ttycharset) character input data would normally cause er-
rors; setting mime-force-sendout will instead, as a last resort, classify
the input as binary data, and therefore allow message creation to be suc-
cessful. (Such content can then be inspected either by installing a
pipe-TYPE/SUBTYPE handler for `application/octet-stream', or possibly au-
tomatically through mime-counter-evidence).
In interactive mode, introduced soon, messages can be sent by calling the
mail command with a list of recipient addresses:
$ s-nail -:/ -Squiet -Semptystart -Sfullnames -Smta=test
"/var/spool/mail/user": 0 messages
? mail "Recipient 1 <rec1@exam.ple>", rec2@exam.ple
...
? # Will do the right thing (tm)
? m rec1@exam.ple rec2@exam.ple
Compose mode
If standard input is a terminal rather than the message to be sent, the
user is expected to type in the message contents. In compose mode lines
beginning with the character `~' (in fact the value of escape) are spe-
cial - these are so-called COMMAND ESCAPES which can be used to read in
files, process shell commands, add and edit attachments and more. For
example ~v or ~e will start the VISUAL text EDITOR, respectively, to re-
vise the message in its current state, ~h allows editing of the most im-
portant message headers, with the potent ~^ custom headers can be cre-
ated, for example (more specifically than with -C and customhdr). [Op-
tion]ally ~? gives an overview of most other available command escapes.
To create file-carbon-copies the special recipient header `Fcc:' may be
used as often as desired, for example via ~^. Its entire value (or body
in standard terms) is interpreted as a folder target, after having been
subject to Filename transformations: this is the only way to create a
file-carbon-copy without introducing an ambiguity regarding the interpre-
tation of the address, file names with leading vertical bars or commer-
cial ats can be used. Like all other recipients `Fcc:' is subject to the
checks of expandaddr. Any local file and pipe command addressee honours
the setting of mbox-fcc-and-pcc.
Once finished with editing the command escape ~. (see there) will call
hooks, insert automatic injections and receivers, leave compose mode and
send the message once it is completed. Aborting letter composition is
possible with either of ~x or ~q, the latter of which will save the mes-
sage in the file denoted by DEAD unless nosave is set. And unless
ignoreeof is set the effect of ~. can also be achieved by typing end-of-
transmission (EOT) via `control-D' (`^D') at the beginning of an empty
line, and ~q is always reachable by typing end-of-text (ETX) twice via
`control-C' (`^C').
The compose mode hooks on-compose-enter, on-compose-splice,
on-compose-leave and on-compose-cleanup may be set to defined macros and
provide reliable and increasingly powerful mechanisms to perform auto-
mated message adjustments dependent on message context, for example addi-
tion of message signatures (message-inject-head, message-inject-tail) or
creation of additional receiver lists (also by setting autocc, autobcc).
To achieve that the command digmsg may be used in order to query and ad-
just status of message(s). The splice hook can also make use of COMMAND
ESCAPES. ([v15 behaviour may differ] The compose mode hooks work for
forward, mail, reply and variants; resend and Resend only provide the
hooks on-resend-enter and on-resend-cleanup, which are pretty restricted
due to the nature of the operation.)
On reading mail, and more on interactive mode
When invoked without addressees S-nail enters interactive mode in which
mails may be read. When used like that the user's system inbox (for more
on mailbox types please see the command folder) is read in and a one line
header of each message therein is displayed if the variable header is
set. The visual style of this summary of headers can be adjusted through
the variable headline and the possible sorting criterion via autosort.
Scrolling through screenfuls of headers can be performed with the command
z. If the initially opened mailbox is empty S-nail will instead exit im-
mediately (after displaying a message) unless the variable emptystart is
set.
At the prompt the command list will give a listing of all available com-
mands and help will [Option]ally give a summary of some common ones. If
the [Option]al documentation strings are available (see features) one can
type `help X' (or `?X') and see the actual expansion of `X' and what its
purpose is, i.e., commands can be abbreviated (note that POSIX defines
some abbreviations, so that the alphabetical order of commands does not
necessarily relate to the abbreviations; it is however possible to define
overwrites with commandalias). These commands can also produce a more
verbose output.
Messages are given numbers (starting at 1) which uniquely identify mes-
sages; the current message - the "dot" - will either be the first new
message, or the first unread message, or the first message of the mail-
box; the internal variable showlast will instead cause usage of the last
message for this purpose. The command headers will display a screenful
of header summaries containing the "dot", whereas from will display only
the summaries of the given messages, defaulting to the "dot".
Message content can be displayed with the command type (`t', alias
print). Here the variable crt controls whether and when S-nail will use
the configured PAGER for display instead of directly writing to the user
terminal screen, the sole difference to the command more, which will al-
ways use the PAGER. The command top will instead only show the first
toplines of a message (maybe even compressed if topsqueeze is set). Mes-
sage display experience may improve by setting and adjusting
mime-counter-evidence, and also see HTML mail and MIME attachments.
By default the current message ("dot") is displayed, but like with many
other commands it is possible to give a fancy message specification (see
Specifying messages), for example `t:u' will display all unread messages,
`t.' will display the "dot", `t 1 5' will type the messages 1 and 5, `t
1-5' will type the messages 1 through 5, and `t-' and `t+' will display
the previous and the next message, respectively. The command search (a
more substantial alias for from) will display a header summary of the
given message specification list instead of their content; the following
will search for subjects:
? from '@Some subject to search for'
In the default setup all header fields of a message will be typed, but
fields can be white- or blacklisted for a variety of applications by us-
ing the command headerpick, e.g., to restrict their display to a very re-
stricted set for type: `headerpick type retain from to cc subject'. In
order to display all header fields of a message regardless of currently
active ignore or retain lists, use the commands Type and Top; Show will
show the raw message content. Note that historically the global
s-nail.rc not only adjusts the list of displayed headers, but also sets
crt. ([v15 behaviour may differ] A yet somewhat restricted) Reliable
scriptable message inspection is available via digmsg.
Dependent upon the configuration a line editor (see the section On
terminal control and line editor) aims at making the user experience with
the many COMMANDS a bit nicer. When reading the system inbox, or when -f
(or folder) specified a mailbox explicitly prefixed with the special `%:'
modifier (to propagate it to a primary system mailbox), then messages
which have been read (see Message states) will be automatically moved to
a secondary mailbox, the user's MBOX file, when the mailbox is left, ei-
ther by changing the active mailbox or by quitting S-nail - this auto-
matic moving from a system- or primary- to the secondary mailbox is not
performed when the variable hold is set. Messages can also be explicitly
moved to other mailboxes, whereas copy keeps the original message. write
can be used to write out data content of specific parts of messages.
After examining a message the user can reply `r' to the sender and all
recipients (which will also be placed in `To:' unless recipients-in-cc is
set), or Reply `R' exclusively to the sender(s). To comply with with the
receivers desired reply address the quadoptions followup-to-honour and
reply-to-honour should usually be set. The commands Lreply and Lfollowup
know how to apply a special addressee massage, see Mailing lists. Depen-
dent on the presence and value of quote the message being replied to will
be included in a quoted form. forwarding a message will allow editing
the new message: the original message will be contained in the message
body, adjusted according to headerpick. It is possible to resend or
Resend messages: the former will add a series of `Resent-' headers,
whereas the latter will not; different to newly created messages editing
is not possible and no copy will be saved even with record unless the ad-
ditional variable record-resent is set. When sending, replying or for-
warding messages comments and full names will be stripped from recipient
addresses unless the internal variable fullnames is set.
Of course messages can be delete `d', and they can spring into existence
again via undelete, or when the S-nail session is ended via the exit or
xit commands to perform a quick program termation. To end a mail pro-
cessing session regularly and perform a full program exit one may issue
the command quit. It will, among others, move read messages to the
secondary mailbox MBOX as necessary, discard deleted messages in the cur-
rent mailbox, and update the [Option]al (see features) line editor
history-file. By the way, whenever the main event loop is about to look
out for the next input line it will trigger the hook on-main-loop-tick.
HTML mail and MIME attachments
HTML-only messages become more and more common, and many messages come
bundled with a bouquet of MIME (Multipurpose Internet Mail Extensions)
parts and attachments. To get a notion of MIME types S-nail has a de-
fault set of types built-in, onto which the content of The mime.types
files will be added (as configured and allowed by
mimetypes-load-control). Types can also become registered with the com-
mand mimetype. To improve interaction with the faulty MIME part declara-
tions of real life mime-counter-evidence will allow verification of the
given assertion, and the possible provision of an alternative, better
MIME type.
Whereas a simple HTML-to-text filter for displaying HTML messages is [Op-
tion]ally supported (indicated by `,+filter-html-tagsoup,' in features),
MIME types other than plain text cannot be handled directly. Instead
programs need to become registered to deal with specific MIME types or
file extensions, either to prepare (re-)integrable plain text versions of
their input (a mode which is called copiousoutput), or to display the
content externally, for example in a graphical window: the latter type is
only considered by and for the command mimeview.
To install a handler program for a MIME type an according
pipe-TYPE/SUBTYPE variable needs to be set; to define a handler for a
file extension pipe-EXTENSION can be used - these handlers take prece-
dence. [Option]ally mail user agent configuration is supported (see The
Mailcap files), and will be queried for display or quote handlers after
the former ones. Type-markers registered via mimetype are the last pos-
sible source for information how to handle a MIME type.
For example, to display HTML messages integrated via the text browsers
lynx(1) or elinks(1), register a MathML MIME type and enable its plain
text display, and to open PDF attachments in an external PDF viewer,
asynchronously and with some other magic attached:
? if "$features" !% ,+filter-html-tagsoup,
? #set pipe-text/html='?* elinks -force-html -dump 1'
? set pipe-text/html='?* lynx -stdin -dump -force_html'
? # Display HTML as plain text instead
? #set pipe-text/html=?t
? endif
? mimetype ?t application/mathml+xml mathml
? wysh set pipe-application/pdf='?&=? \
trap "rm -f \"${MAILX_FILENAME_TEMPORARY}\"" EXIT;\
trap "trap \"\" INT QUIT TERM; exit 1" INT QUIT TERM;\
mupdf "${MAILX_FILENAME_TEMPORARY}"'
Mailing lists
Known or subscribed-to mailing lists may be flagged in the summary of
headers (headline format character `%L'), and will gain special treatment
when sending mails: the variable followup-to-honour will ensure that a
`Mail-Followup-To:' header is honoured when a message is being replied to
(reply, followup, Lreply, Lfollowup), and followup-to controls creation
of this header when creating mails, if the necessary user setup (from,
sender); is available; then, it may also be created automatically, for
example when list-replying via Lreply or Lfollowup, when followup or
reply is used and the messages `Mail-Followup-To:' is honoured etc.
The commands mlist and mlsubscribe manage S-nails notion of which ad-
dresses are mailing lists. With the [Option]al regular expression sup-
port any address which contains any of the magic regular expression char-
acters (`^[*+?|$'; see re_format(7) or regex(7), dependent on the host
system) will be compiled and used as one, possibly matching many ad-
dresses. It is not possible to escape the "magic": in order to match
special characters as-is, bracket expressions must be used, for example
`search @subject@'[[]open bracket''.
? set followup-to followup-to-honour=ask-yes \
reply-to-honour=ask-yes
? mlist a1@b1.c1 a2@b2.c2 '.*@lists\.c3$'
? mlsubscribe a4@b4.c4 exact@lists.c3
Known and subscribed lists differ in that for the latter the users ad-
dress is not part of a generated `Mail-Followup-To:'. There are excep-
tions, for example if multiple lists are addressed and not all have the
subscription attribute. When replying to a message its list address
(`List-Post:' header) is automatically and temporarily treated like a
known mlist; dependent on the variable reply-to-honour an existing
`Reply-To:' is used instead (if it is a single address on the same domain
as `List-Post:') in order to accept a list administrator's wish that is
supposed to have been manifested like that.
For convenience and compatibility with mail programs that do not honour
the non-standard M-F-T, an automatic user entry in the carbon-copy `Cc:'
address list of generated message can be created by setting
followup-to-add-cc. This entry will be added whenever the user will be
placed in the `Mail-Followup-To:' list, and is not a regular addressee
already. reply-to-swap-in tries to deal with the address rewriting that
many mailing-lists nowadays perform to work around DKIM / DMARC etc.
standard imposed problems.
Signed and encrypted messages with S/MIME
[Option] S/MIME provides two central mechanisms: message signing and mes-
sage encryption. A signed message contains some data in addition to the
regular text. The data can be used to verify that the message has been
sent using a valid certificate, that the sender address matches that in
the certificate, and that the message text has not been altered. Signing
a message does not change its regular text; it can be read regardless of
whether the recipients software is able to handle S/MIME. It is thus
usually possible to sign all outgoing messages if so desired.
Encryption, in contrast, makes the message text invisible for all people
except those who have access to the secret decryption key. To encrypt a
message, the specific recipients public encryption key must be known. It
is therefore not possible to send encrypted mail to people unless their
key has been retrieved from either previous communication or public key
directories. Because signing is performed with private keys, and encryp-
tion with public keys, messages should always be signed before being en-
crypted.
A central concept to S/MIME is that of the certification authority (CA).
A CA is a trusted institution that issues certificates. For each of
these certificates it can be verified that it really originates from the
CA, provided that the CA's own certificate is previously known. A set of
CA certificates is usually delivered and installed together with the
cryptographical library that is used on the local system. Therefore rea-
sonable security for S/MIME on the Internet is provided if the source
that provides that library installation is trusted. It is also possible
to use a specific pool of trusted certificates. If this is desired,
smime-ca-no-defaults should be set to avoid using the default certificate
pool, and smime-ca-file and/or smime-ca-dir should be pointed to a
trusted pool of certificates. A certificate cannot be more secure than
the method its CA certificate has been retrieved with.
This trusted pool of certificates is used by the command verify to ensure
that the given S/MIME messages can be trusted. If so, verified sender
certificates that were embedded in signed messages can be saved locally
with the command certsave, and used by S-nail to encrypt further communi-
cation with these senders:
? certsave FILENAME
? set smime-encrypt-USER@HOST=FILENAME \
smime-cipher-USER@HOST=AES256
To sign outgoing messages, in order to allow receivers to verify the ori-
gin of these messages, a personal S/MIME certificate is required. S-nail
supports password-protected personal certificates (and keys), see
smime-sign-cert. The section On URL syntax and credential lookup gives
an overview of the possible sources of user credentials, and S/MIME step
by step shows examplarily how a private S/MIME certificate can be ob-
tained. In general, if such a private key plus certificate "pair" is
available, all that needs to be done is to set some variables:
? set smime-sign-cert=ME@exam.ple.paired \
smime-sign-digest=SHA512 \
smime-sign from=myname@my.host
Variables of interest for S/MIME in general are smime-ca-dir,
smime-ca-file, smime-ca-flags, smime-ca-no-defaults, smime-crl-dir,
smime-crl-file. For S/MIME signing of interest are smime-sign,
smime-sign-cert, smime-sign-include-certs and smime-sign-digest. Addi-
tional variables of interest for S/MIME en- and decryption: smime-cipher
and smime-encrypt-USER@HOST. Variables of secondary interest may be
content-description-smime-message and
content-description-smime-signature. S/MIME is available if `,+smime,'
is included in features.
[v15 behaviour may differ] Note that neither S/MIME signing nor encryp-
tion applies to message subjects or other header fields yet. Thus they
may not contain sensitive information for encrypted messages, and cannot
be trusted even if the message content has been verified. When sending
signed messages, it is recommended to repeat any important header infor-
mation in the message text.
On URL syntax and credential lookup
For accessing protocol-specific resources Uniform Resource Locators (URL,
RFC 3986) have become omnipresent. Here they are expected in a
"normalized" variant, not used in data exchange, but only meant as a com-
pact, easy-to-use way of defining and representing information in a well-
known notation; as such they do not conform to any real standard. Op-
tional parts are placed in brackets `[]', optional either because there
also exist other ways to define the information, or because the part is
protocol specific. `/path' for example is used by the [Option]al Maildir
folder type and the IMAP protocol, but not by POP3. If `USER' and
`PASSWORD' are included in an URL server specification, URL percent en-
coded (RFC 3986) forms are needed, generable with urlcodec.
PROTOCOL://[USER[:PASSWORD]@]server[:port][/path]
Often INTERNAL VARIABLES exist in multiple versions, called "variable
chains" in this document: the plain `variable' as well as `variable-HOST'
and `variable-USER@HOST'. If a port was specified `HOST' really means
`server:port', not `server'. And this `USER' is never in URL percent en-
coded form. For example, whether the hypothetical `smtp://wings%3Aof
@a.dove' including user and password was used, or whether it was
`smtp://a.dove' and it came from a different source, to lookup the chain
tls-config-pairs first `tls-config-pairs-wings:of@a.dove' is looked up,
then `tls-config-pairs-a.dove', before finally looking up the plain vari-
able.
The logic to collect (an accounts) credential information is as follows:
o A user is always required. If no `USER' has been given in the URL
the variables user-HOST and user are looked up. Afterwards, when en-
forced by the [Option]al variables netrc-lookup-HOST or netrc-lookup,
The .netrc file of the user will be searched for a `HOST' specific
entry which provides a `login' name: only unambiguous entries are
used (one possible matching entry for `HOST').
If there is still no `USER' then the verified LOGNAME, known to be a
valid user on the current host, is used.
o Authentication: unless otherwise noted the chain
PROTOCOL-auth-USER@HOST, PROTOCOL-auth-HOST, PROTOCOL-auth is
checked, falling back to a protocol-specific default as necessary.
o If no `PASSWORD' has been given in the URL, then if the `USER' has
been found through the [Option]al netrc-lookup, that may have also
provided the password. Otherwise the chain password-USER@HOST,
password-HOST, password is looked up.
Thereafter the (now complete) [Option]al chain
netrc-lookup-USER@HOST, netrc-lookup-HOST, netrc-lookup is checked,
if set the netrc cache is searched for a password only (multiple user
accounts for a single machine may exist as well as a fallback entry
without user but with a password).
If at that point there is still no password available, but the (pro-
tocols') chosen authentication type requires a password, then in in-
teractive mode the user will be prompted on the terminal.
Note: S/MIME verification works relative to the values found in the
`From:' (or `Sender:') header field(s), which means the values of
smime-sign, smime-sign-cert, smime-sign-include-certs and
smime-sign-digest will not be looked up using the `USER' and `HOST'
chains from above, but instead use the corresponding values from the mes-
sage that is being worked on. If no address matches we assume and use
the setting of from. In unusual cases multiple and different `USER' and
`HOST' combinations may therefore be involved - on the other hand those
unusual cases become possible. The usual case is as short as:
set mta=smtp://USER:PASS@HOST smtp-use-starttls \
smime-sign smime-sign-cert=+smime.pair \
from=myname@my.host
The section EXAMPLES contains complete example configurations.
Encrypted network communication
[Option] SSL (Secure Sockets Layer) aka its successor TLS (Transport
Layer Security) are protocols which aid in securing communication by pro-
viding a safely initiated and encrypted network connection. A central
concept of TLS are certificates: as part of each network connection setup
a (set of) certificates will be exchanged through which the identity of
the network peer can be cryptographically verified; if possible the
TLS/SNI (ServerNameIndication) extension will be enabled to allow servers
fine-grained control over the certificates being used. A locally in-
stalled pool of trusted certificates will then be inspected, and verifi-
cation will succeed if it contains a(n in)direct signer of the presented
certificate(s).
The local pool of trusted so-called CA (Certification Authority) certifi-
cates is usually delivered with and used along the TLS library. A custom
pool of trusted certificates can be selected by pointing tls-ca-file
and/or (with special preparation) tls-ca-dir to the desired location;
setting tls-ca-no-defaults in addition will avoid additional inspection
of the default pool. A certificate cannot be more secure than the method
its CA certificate has been retrieved with. For inspection or other pur-
poses, the certificate of a server (as seen when connecting to it) can be
fetched with the command tls (port can usually be the protocol name, too,
and tls-verify is taken into account here):
$ s-nail -vX 'tls certchain SERVER-URL[:PORT]; x'
A local pool of CA certificates is not strictly necessary, however,
server certificates can also be verified via their fingerprint. For this
a message digest will be calculated and compared against the variable
chain tls-fingerprint, and verification will succeed if the fingerprint
matches. The message digest (algorithm) can be configured via the vari-
able chain tls-fingerprint-digest; tls can again be used:
$ s-nail -X 'wysh set verbose; tls fingerprint SERVER-URL[:PORT]; x'
It depends on the used protocol whether encrypted communication is possi-
ble, and which configuration steps have to be taken to enable it. Some
protocols, like POP3S, are implicitly encrypted, others, like POP3, can
upgrade a plain text connection if so requested. For example, to use the
`STLS' that POP3 offers (a member of) the variable (chain)
pop3-use-starttls needs to be set, with convenience via shortcut:
shortcut encpop1 pop3s://pop1.exam.ple
shortcut encpop2 pop3://pop2.exam.ple
set pop3-use-starttls-pop2.exam.ple
set mta=smtps://smtp.exam.ple:465
set mta=smtp://smtp.exam.ple smtp-use-starttls
Normally that is all there is to do, given that TLS libraries try to pro-
vide safe defaults, plenty of knobs however exist to adjust settings.
For example certificate verification settings can be fine-tuned via
tls-ca-flags, and the TLS configuration basics are accessible via
tls-config-pairs, for example to control protocol versions or cipher
lists. In the past hints on how to restrict the set of protocols to
highly secure ones were indicated, but as of the time of this writing the
list of protocols or ciphers may need to become relaxed in order to be
able to connect to some servers; the following example allows connecting
to a "Lion" that uses OpenSSL 0.9.8za from June 2014 (refer to INTERNAL
VARIABLES for more on variable chains):
wysh set tls-config-pairs-lion@exam.ple='MinProtocol=TLSv1.1,\
CipherString=TLSv1.2:!aNULL:!eNULL:\
ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:\
DHE-RSA-AES256-SHA:@STRENGTH'
The OpenSSL program ciphers(1) should be referred to when creating a cus-
tom cipher list. Variables of interest for TLS in general are
tls-ca-dir, tls-ca-file, tls-ca-flags, tls-ca-no-defaults,
tls-config-file, tls-config-module, tls-config-pairs, tls-crl-dir,
tls-crl-file, tls-rand-file as well as tls-verify. Also see
tls-features. TLS is available if `+tls' is included in features.
Character sets
[Option] The user's locale environment is detected by looking at the
LC_ALL environment variable. The internal variable ttycharset will be
set to the detected terminal character set accordingly, and will thus
show up in the output of commands like set and varshow. This character
set will be targeted when trying to display data, and user input data is
expected to be in this character set, too.
When creating messages their character input data is classified. 7-bit
clean text data and attachments will be classified as charset-7bit.
8-bit data will [Option]ally be converted into members of sendcharsets
until a character set conversion succeeds. charset-8bit is the implied
default last member of this list. If no 8-bit character set is capable
to represent input data, no message will be sent, and its text will op-
tionally be saved in DEAD. If that is not acceptable, for example in
script environments, mime-force-sendout can be set to force sending of
non-convertible data as `application/octet-stream' classified binary con-
tent instead: like this receivers still have the option to inspect mes-
sage content (for example via mime-counter-evidence). If the [Option]al
character set conversion is not available (features misses `,+iconv,'),
ttycharset is the only supported character set for non 7-bit clean data,
and it is simply assumed it can be used to exchange 8-bit messages.
ttycharset may also be given an explicit value to send mail in a com-
pletely "faked" locale environment, which can be used to generate and
send for example 8-bit UTF-8 input data in a pure 7-bit US-ASCII
`LC_ALL=C' environment (an example of this can be found in the section On
sending mail, and non-interactive mode). Doing so does not mean much be-
side that since several aspects of the real character set are implied by
the locale environment of the system, which stays unaffected by
ttycharset.
Classifying 7-bit clean data as charset-7bit is a problem if the input
character set (ttycharset) is a multibyte character set that is itself
7-bit clean. For example, the Japanese character set ISO-2022-JP is, but
is capable to encode the rich set of Japanese Kanji, Hiragana and
Katakana characters: in order to notify receivers of this character set
the mail message must be MIME encoded so that the character set
ISO-2022-JP can be advertised, otherwise an invalid email message would
result! To achieve this, the variable charset-7bit can be set to
ISO-2022-JP. (Today a better approach regarding email is the usage of
UTF-8, which uses 8-bit bytes for non-US-ASCII data.)
When replying to a message and the variable reply-in-same-charset is set,
the character set of the message being replied to is tried first as a
target character set (still being a subject of charsetalias filtering,
however). Another opportunity is sendcharsets-else-ttycharset to reflect
the user's locale environment automatically, it will treat ttycharset as
an implied member of (an unset) sendcharsets.
[Option] When reading messages, their text data is converted into
ttycharset as necessary in order to display them on the user's terminal.
Unprintable characters and invalid byte sequences are detected and re-
placed by substitution characters. Character set mappings for source
character sets can be established with charsetalias, which may be handy
to work around faulty or incomplete character set catalogues (one could
for example add a missing LATIN1 to ISO-8859-1 mapping), or to enforce
treatment of one character set as another one ("interpret LATIN1 as
CP1252"). Also see charset-unknown-8bit to deal with another hairy as-
pect of message interpretation.
In general, if a message saying "cannot convert from a to b" appears, ei-
ther some characters are not appropriate for the currently selected (ter-
minal) character set, or the needed conversion is not supported by the
system. In the first case, it is necessary to set an appropriate
LC_CTYPE locale and/or the variable ttycharset. The best results are
usually achieved when running in a UTF-8 locale on a UTF-8 capable termi-
nal, in which case the full Unicode spectrum of characters is available.
In this setup characters from various countries can be displayed, while
it is still possible to use more simple character sets for sending to re-
tain maximum compatibility with older mail clients.
On the other hand the POSIX standard defines a locale-independent 7-bit
"portable character set" that should be used when overall portability is
an issue, the even more restricted subset named "portable filename
character set" consists of A-Z, a-z, 0-9, period `.', underscore `_' and
hyphen-minus `-'.
Message states
S-nail differentiates in between several message states; the current
state will be reflected in the summary of headers if the attrlist of the
configured headline allows, and Specifying messages dependent on their
state is possible. When operating on the system inbox, or in any other
primary system mailbox, special actions, like the automatic moving of
messages to the secondary mailbox MBOX, may be applied when the mailbox
is left (also implicitly by program termination, unless the command exit
was used) - however, because this may be irritating to users which are
used to "more modern" mail-user-agents, the provided global s-nail.rc
template sets the internal hold and keepsave variables in order to sup-
press this behaviour.
`new' Message has neither been viewed nor moved to any other state.
Such messages are retained even in the primary system mailbox.
`unread' Message has neither been viewed nor moved to any other state,
but the message was present already when the mailbox has been
opened last: Such messages are retained even in the primary
system mailbox.
`read' The message has been processed by one of the following com-
mands: ~f, ~m, ~F, ~M, copy, mbox, next, pipe, Print, print,
top, Type, type, undelete. The commands dp and dt will always
try to automatically "step" and type the "next" logical mes-
sage, and may thus mark multiple messages as read, the delete
command will do so if the internal variable autoprint is set.
Except when the exit command is used, messages that are in a
primary system mailbox and are in `read' state when the mailbox
is left will be saved in the secondary mailbox MBOX unless the
internal variable hold it set.
`deleted' The message has been processed by one of the following com-
mands: delete, dp, dt. Only undelete can be used to access
such messages.
`preserved' The message has been processed by a preserve command and it
will be retained in its current location.
`saved' The message has been processed by one of the following com-
mands: save or write. Unless when the exit command is used,
messages that are in a primary system mailbox and are in
`saved' state when the mailbox is left will be deleted; they
will be saved in the secondary mailbox MBOX when the internal
variable keepsave is set.
In addition to these message states, flags which otherwise have no tech-
nical meaning in the mail system except allowing special ways of address-
ing them when Specifying messages can be set on messages. These flags
are saved with messages and are thus persistent, and are portable between
a set of widely used MUAs.
answered Mark messages as having been answered.
draft Mark messages as being a draft.
flag Mark messages which need special attention.
Specifying messages
[Only new quoting rules] COMMANDS which take Message list arguments, such
as search, type, copy, and delete, can perform actions on a number of
messages at once. Specifying invalid messages, or using illegal syntax,
will cause errors to be reported through the INTERNAL VARIABLES !, ^ERR
and companions, as well as the command exit status ?.
For example, `delete 1 2' deletes the messages 1 and 2, whereas `delete
1-5' will delete the messages 1 through 5. In sorted or threaded mode
(see the sort command), `delete 1-5' will delete the messages that are
located between (and including) messages 1 through 5 in the
sorted/threaded order, as shown in the headers summary.
Errors can for example be ^ERR-BADMSG when requesting an invalid message,
^ERR-NOMSG if no applicable message can be found, ^ERR-CANCELED for miss-
ing informational data (mostly thread-related). ^ERR-INVAL for invalid
syntax as well as ^ERR-IO for input/output errors can happen. The fol-
lowing special message names exist:
. The current message, the so-called "dot".
; The message that was previously the current message; needs to
be quoted.
, The parent message of the current message, that is the message
with the Message-ID given in the `In-Reply-To:' field or the
last entry of the `References:' field of the current message.
- The previous undeleted message, or the previous deleted message
for the undelete command; In sorted or `thread'ed mode, the
previous such message in the according order.
+ The next undeleted message, or the next deleted message for the
undelete command; In sorted or `thread'ed mode, the next such
message in the according order.
^ The first undeleted message, or the first deleted message for
the undelete command; In sorted or `thread'ed mode, the first
such message in the according order.
$ The last message; In sorted or `thread'ed mode, the last such
message in the according order. Needs to be quoted.
&x In `thread'ed sort mode, selects the message addressed with x,
where x is any other message specification, and all messages
from the thread that begins at it. Otherwise it is identical
to x. If x is omitted, the thread beginning with the current
message is selected.
* All messages.
` All messages that were included in the Message list arguments
of the previous command; needs to be quoted. (A convenient way
to read all new messages is to select them via `from :n', as
below, and then to read them in order with the default command
-- next -- simply by successively typing ``'; for this to work
showlast must be set.)
x-y An inclusive range of message numbers. Selectors that may also
be used as endpoints include any of .;-+^$.
address A case-insensitive "any substring matches" search against the
`From:' header, which will match addresses (too) even if
showname is set (and POSIX says "any address as shown in a
header summary shall be matchable in this form"); However, if
the allnet variable is set, only the local part of the address
is evaluated for the comparison, not ignoring case, and the
setting of showname is completely ignored. For finer control
and match boundaries use the `@' search expression.
/string All messages that contain string in the subject field (case ig-
nored according to locale). See also the searchheaders vari-
able. If string is empty, the string from the previous speci-
fication of that type is used again.
[@name-list]@expr
All messages that contain the given case-insensitive search
expression; If the [Option]al regular expression support is
available expr will be interpreted as (an extended) one if any
of the magic regular expression characters is seen. If the op-
tional @name-list part is missing the search is restricted to
the subject field body, but otherwise name-list specifies a
comma-separated list of header fields to search, for example
'@to,from,cc@Someone i ought to know'
In order to search for a string that includes a `@' (commercial
at) character the name-list is effectively non-optional, but
may be given as the empty string. Also, specifying an empty
search expression will effectively test for existence of the
given header fields. Some special header fields may be abbre-
viated: `f', `t', `c', `b' and `s' will match `From', `To',
`Cc', `Bcc' and `Subject', respectively and case-insensitively.
[Option]ally, and just like expr, name-list will be interpreted
as (an extended) regular expression if any of the magic regular
expression characters is seen.
The special names `header' or `<' can be used to search in (all
of) the header(s) of the message, and the special names `body'
or `>' and `text' or `=' will perform full text searches -
whereas the former searches only the body, the latter also
searches the message header ([v15 behaviour may differ] this
mode yet brute force searches over the entire decoded content
of messages, including administrativa strings).
This specification performs full text comparison, but even with
regular expression support it is almost impossible to write a
search expression that safely matches only a specific address
domain. To request that the body content of the header is
treated as a list of addresses, and to strip those down to the
plain email address which the search expression is to be
matched against, prefix the effective name-list with a tilde
`~':
'@~f,c@@a\.safe\.domain\.match$'
:c All messages of state or with matching condition `c', where `c'
is one or multiple of the following colon modifiers:
a answered messages (cf. the variable markanswered).
d `deleted' messages (for the undelete and from com-
mands only).
f flagged messages.
L Messages with receivers that match mlsubscribed ad-
dresses.
l Messages with receivers that match mlisted addresses.
n `new' messages.
o Old messages (any not in state `read' or `new').
r `read' messages.
S [Option] Messages with unsure spam classification
(see Handling spam).
s [Option] Messages classified as spam.
t Messages marked as draft.
u `unread' messages.
[Option] IMAP-style SEARCH expressions may also be used. These consist
of keywords and criterions, and because Message list arguments are split
into tokens according to Shell-style argument quoting it is necessary to
quote the entire IMAP search expression in order to ensure that it re-
mains a single token. This addressing mode is available with all types
of mailbox folders; S-nail will perform the search locally as necessary.
Strings must be enclosed by double quotation marks `"' in their entirety
if they contain whitespace or parentheses; within the quotes, only re-
verse solidus `\' is recognized as an escape character. All string
searches are case-insensitive. When the description indicates that the
"envelope" representation of an address field is used, this means that
the search string is checked against both a list constructed as
'("name" "source" "local-part" "domain-part")'
for each address, and the addresses without real names from the respec-
tive header field. These search expressions can be nested using paren-
theses, see below for examples.
(criterion)
All messages that satisfy the given criterion.
(criterion1 criterion2 ... criterionN)
All messages that satisfy all of the given criteria.
(or criterion1 criterion2)
All messages that satisfy either criterion1 or criterion2, or
both. To connect more than two criteria using `or' specifica-
tions have to be nested using additional parentheses, as with
`(or a (or b c))', since `(or a b c)' really means `((a or b)
and c)'. For a simple `or' operation of independent criteria
on the lowest nesting level, it is possible to achieve similar
effects by using three separate criteria, as with `(a) (b)
(c)'.
(not criterion)
All messages that do not satisfy criterion.
(bcc "string")
All messages that contain string in the envelope representation
of the `Bcc:' field.
(cc "string")
All messages that contain string in the envelope representation
of the `Cc:' field.
(from "string")
All messages that contain string in the envelope representation
of the `From:' field.
(subject "string")
All messages that contain string in the `Subject:' field.
(to "string")
All messages that contain string in the envelope representation
of the `To:' field.
(header name "string")
All messages that contain string in the specified `Name:'
field.
(body "string")
All messages that contain string in their body.
(text "string")
All messages that contain string in their header or body.
(larger size)
All messages that are larger than size (in bytes).
(smaller size)
All messages that are smaller than size (in bytes).
(before date)
All messages that were received before date, which must be in
the form `d[d]-mon-yyyy', where `d' denotes the day of the
month as one or two digits, `mon' is the name of the month -
one of `Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec', and
`yyyy' is the year as four digits, for example `28-Dec-2012'.
(on date)
All messages that were received on the specified date.
(since date)
All messages that were received since the specified date.
(sentbefore date)
All messages that were sent on the specified date.
(senton date)
All messages that were sent on the specified date.
(sentsince date)
All messages that were sent since the specified date.
() The same criterion as for the previous search. This specifica-
tion cannot be used as part of another criterion. If the pre-
vious command line contained more than one independent crite-
rion then the last of those criteria is used.
On terminal control and line editor
[Option] Terminal control through one of the standard UNIX libraries,
Termcap Access Library (libtermcap, -ltermcap) or Terminal Information
Library (libterminfo, -lterminfo), may be available. For the TERMinal
defined in the environment interactive usage aspects, for example
Coloured display, and insight of cursor and function keys for the Mailx-
Line-Editor (MLE), will be enhanced or enabled. Library interaction can
be disabled on a per-invocation basis via termcap-disable, whereas the
internal variable termcap is always used as a preferred source of termi-
nal capabilities. (For a usage example see the FAQ entry Not
"defunctional", but the editor key does not work.)
[Option] The built-in Mailx-Line-Editor (MLE) should work in all environ-
ments which comply to the ISO C standard ISO/IEC 9899/AMD1:1995
("ISO C90, Amendment 1"), and will support wide glyphs if possible (the
necessary functionality had been removed from ISO C, but was included in
X/Open Portability Guide Issue 4 ("XPG4")). Usage of a line editor in
interactive mode can be prevented by setting line-editor-disable. Espe-
cially if the [Option]al terminal control support is missing setting en-
tries in termcap will help shall the MLE misbehave, see there for more.
The MLE can support a little bit of colour.
[Option] If the history feature is available then input from line editor
prompts will be saved in a history list that can be searched in and be
expanded from. Such saving can be prevented by prefixing input with any
amount of whitespace. Aspects of history, like allowed content and maxi-
mum size, as well as whether history shall be saved persistently, can be
configured with the internal variables history-file, history-gabby,
history-gabby-persist and history-size. There also exists the macro hook
on-history-addition which can be used to apply finer control on what en-
ters history.
The MLE supports a set of editing and control commands. By default (as)
many (as possible) of these will be assigned to a set of single-letter
control codes, which should work on any terminal (and can be generated by
holding the "control" key while pressing the key of desire, for example
`control-D'). If the [Option]al bind command is available then the MLE
commands can also be accessed freely by assigning the command name, which
is shown in parenthesis in the list below, to any desired key-sequence,
and the MLE will instead and also use bind to establish its built-in key
bindings (more of them if the [Option]al terminal control is available),
an action which can then be suppressed completely by setting
line-editor-no-defaults. Shell-style argument quoting notation is used
in the following:
`\cA' Go to the start of the line (mle-go-home).
`\cB' Move the cursor backward one character (mle-go-bwd).
`\cC' raise(3) `SIGINT' (mle-raise-int).
`\cD' Forward delete the character under the cursor; quits S-nail if
used on the empty line unless the internal variable ignoreeof
is set (mle-del-fwd).
`\cE' Go to the end of the line (mle-go-end).
`\cF' Move the cursor forward one character (mle-go-fwd).
`\cG' Cancel current operation, full reset. If there is an active
history search or tabulator expansion then this command will
first reset that, reverting to the former line content; thus a
second reset is needed for a full reset in this case
(mle-reset).
`\cH' Backspace: backward delete one character (mle-del-bwd).
`\cI' [Only new quoting rules] Horizontal tabulator: try to expand
the word before the cursor, supporting the usual Filename
transformations (mle-complete; this is affected by
mle-quote-rndtrip and line-editor-cpl-word-breaks).
`\cJ' Newline: commit the current line (mle-commit).
`\cK' Cut all characters from the cursor to the end of the line
(mle-snarf-end).
`\cL' Repaint the line (mle-repaint).
`\cN' [Option] Go to the next history entry (mle-hist-fwd).
`\cO' ([Option]ally context-dependent) Invokes the command dt.
`\cP' [Option] Go to the previous history entry (mle-hist-bwd).
`\cQ' Toggle roundtrip mode shell quotes, where produced, on and off
(mle-quote-rndtrip). This setting is temporary, and will be
forgotten once the command line is committed; also see shcodec.
`\cR' [Option] Complete the current line from (the remaining) older
history entries (mle-hist-srch-bwd).
`\cS' [Option] Complete the current line from (the remaining) newer
history entries (mle-hist-srch-fwd).
`\cT' Paste the snarf buffer (mle-paste).
`\cU' The same as `\cA' followed by `\cK' (mle-snarf-line).
`\cV' Prompts for a Unicode character (hexadecimal number without
prefix, see vexpr) to be inserted (mle-prompt-char). Note this
command needs to be assigned to a single-letter control code in
order to become recognized and executed during input of a key-
sequence (only three single-letter control codes can be used
for that shortcut purpose); this control code is then special-
treated and thus cannot be part of any other sequence (because
it will trigger the mle-prompt-char function immediately).
`\cW' Cut the characters from the one preceding the cursor to the
preceding word boundary (mle-snarf-word-bwd).
`\cX' Move the cursor forward one word boundary (mle-go-word-fwd).
`\cY' Move the cursor backward one word boundary (mle-go-word-bwd).
`\cZ' raise(3) `SIGTSTP' (mle-raise-tstp).
`\c[' Escape: reset a possibly used multibyte character input state
machine and [Option]ally a lingering, incomplete key binding
(mle-cancel). This command needs to be assigned to a single-
letter control code in order to become recognized and executed
during input of a key-sequence (only three single-letter con-
trol codes can be used for that shortcut purpose). This con-
trol code may also be part of a multi-byte sequence, but if a
sequence is active and the very control code is currently also
an expected input, then the active sequence takes precedence
and will consume the control code.
`\c\' ([Option]ally context-dependent) Invokes the command `z+'.
`\c]' ([Option]ally context-dependent) Invokes the command `z$'.
`\c^' ([Option]ally context-dependent) Invokes the command `z0'.
`\c_' Cut the characters from the one after the cursor to the suc-
ceeding word boundary (mle-snarf-word-fwd).
`\c?' Backspace: mle-del-bwd.
- mle-bell: ring the audible bell.
- [Option] mle-clear-screen: move the cursor home and clear the
screen.
- mle-fullreset: different to mle-reset this will immediately re-
set a possibly active search etc.
- mle-go-screen-bwd: move the cursor backward one screen width.
- mle-go-screen-fwd: move the cursor forward one screen width.
- mle-raise-quit: raise(3) `SIGQUIT'.
Coloured display
[Option] Colours and font attributes through ANSI a.k.a. ISO 6429 SGR
(select graphic rendition) escape sequences are optionally supported.
Usage of colours and font attributes solely depends upon the capability
of the detected terminal type (TERM), and as fine-tuned through termcap.
Colours and font attributes can be managed with the multiplexer command
colour, and uncolour removes the given mappings. Setting colour-disable
suppresses usage of colour and font attribute sequences, while leaving
established mappings unchanged.
Whether actually applicable colour and font attribute sequences should
also be generated when output is going to be paged through the external
PAGER (also see crt) depends upon the setting of colour-pager, because
pagers usually need to be configured in order to support ISO escape se-
quences. Knowledge of some widely used pagers is however built-in, and
in a clean environment it is often enough to simply set colour-pager;
please refer to that variable for more on this topic.
It might make sense to conditionalize colour setup on interactive mode
via if (`terminal' indeed means "interactive"):
if terminal && "$features" =% ,+colour,
colour iso view-msginfo ft=bold,fg=green
colour iso view-header ft=bold,fg=red (from|subject) # regex
colour iso view-header fg=red
uncolour iso view-header from,subject
colour iso view-header ft=bold,fg=magenta,bg=cyan
colour 256 view-header ft=bold,fg=208,bg=230 "subject,from"
colour mono view-header ft=bold
colour mono view-header ft=bold,ft=reverse subject,from
endif
Handling spam
[Option] S-nail can make use of several spam interfaces for the purpose
of identification of, and, in general, dealing with spam messages. A
precondition of most commands in order to function is that the
spam-interface variable is set to one of the supported interfaces.
Specifying messages that have been identified as spam is possible via
their (volatile) `is-spam' state by using the `:s' and `:S' specifica-
tions, and their attrlist entries will be used when displaying the
headline in the summary of headers.
o spamrate rates the given messages and sets their `is-spam' flag ac-
cordingly. If the spam interface offers spam scores these can be
shown in headline by using the format `%$'.
o spamham, spamspam and spamforget will interact with the Bayesian fil-
ter of the chosen interface and learn the given messages as "ham" or
"spam", respectively; the last command can be used to cause
"unlearning" of messages; it adheres to their current `is-spam' state
and thus reverts previous teachings.
o spamclear and spamset will simply set and clear, respectively, the
mentioned volatile `is-spam' message flag, without any interface in-
teraction.
The spamassassin(1) based spam-interface `spamc' requires a running in-
stance of the spamd(1) server in order to function, started with the op-
tion --allow-tell shall Bayesian filter learning be possible.
$ spamd -i localhost:2142 -i /tmp/.spamsock -d [-L] [-l]
$ spamd --listen=localhost:2142 --listen=/tmp/.spamsock \
--daemonize [--local] [--allow-tell]
Thereafter S-nail can make use of these interfaces:
$ s-nail -Sspam-interface=spamc -Sspam-maxsize=500000 \
-Sspamc-command=/usr/local/bin/spamc \
-Sspamc-arguments="-U /tmp/.spamsock" -Sspamc-user=
or
$ s-nail -Sspam-interface=spamc -Sspam-maxsize=500000 \
-Sspamc-command=/usr/local/bin/spamc \
-Sspamc-arguments="-d localhost -p 2142" -Sspamc-user=
Using the generic filter approach allows usage of programs like
bogofilter(1). Here is an example, requiring it to be accessible via
PATH:
$ s-nail -Sspam-interface=filter -Sspam-maxsize=500000 \
-Sspamfilter-ham="bogofilter -n" \
-Sspamfilter-noham="bogofilter -N" \
-Sspamfilter-nospam="bogofilter -S" \
-Sspamfilter-rate="bogofilter -TTu 2>/dev/null" \
-Sspamfilter-spam="bogofilter -s" \
-Sspamfilter-rate-scanscore="1;^(.+)$"
Because messages must exist on local storage in order to be scored (or
used for Bayesian filter training), it is possibly a good idea to perform
the local spam check last. Spam can be checked automatically when open-
ing specific folders by setting a specialized form of the internal vari-
able folder-hook.
define spamdelhook {
# Server side DCC
spamset (header x-dcc-brand-metrics "bulk")
# Server-side spamassassin(1)
spamset (header x-spam-flag "YES")
del :s # TODO we HAVE to be able to do `spamrate :u ! :sS'
move :S +maybe-spam
spamrate :u
del :s
move :S +maybe-spam
}
set folder-hook-SOMEFOLDER=spamdelhook
See also the documentation for the variables spam-interface,
spam-maxsize, spamc-command, spamc-arguments, spamc-user, spamfilter-ham,
spamfilter-noham, spamfilter-nospam, spamfilter-rate and
spamfilter-rate-scanscore.
COMMANDS
S-nail reads input in lines. An unquoted reverse solidus `\' at the end
of a command line "escapes" the newline character: it is discarded and
the next line of input is used as a follow-up line, with all leading
whitespace removed; once an entire line is completed, the whitespace
characters space, tabulator, newline as well as those defined by the
variable ifs are removed from the beginning and end. Placing any white-
space characters at the beginning of a line will prevent a possible addi-
tion of the command line to the [Option]al history.
The beginning of such input lines is then scanned for the name of a known
command: command names may be abbreviated, in which case the first com-
mand that matches the given prefix will be used. Command modifiers may
prefix a command in order to modify its behaviour. A name may also be a
commandalias, which will become expanded until no more expansion is pos-
sible. Once the command that shall be executed is known, the remains of
the input line will be interpreted according to command-specific rules,
documented in the following.
This behaviour is different to the sh(1)ell, which is a programming lan-
guage with syntactic elements of clearly defined semantics, and therefore
capable to sequentially expand and evaluate individual elements of a
line. `? set one=value two=$one' for example will never possibly assign
value to one, because the variable assignment is performed no sooner but
by the command (set), long after the expansion happened.
A list of all commands in lookup order is dumped by the command list.
[Option]ally the command help (or ?), when given an argument, will show a
documentation string for the command matching the expanded argument, as
in `?t', which should be a shorthand of `?type'; with these documentation
strings both commands support a more verbose listing mode which includes
the argument type of the command and other information which applies; a
handy suggestion might thus be:
? define __xv {
# Before v15: need to enable sh(1)ell-style on _entire_ line!
localopts yes;wysh set verbose;ignerr eval "${@}";return ${?}
}
? commandalias xv '\call __xv'
? xv help set
Command modifiers
Commands may be prefixed by none to multiple command modifiers. Some
command modifiers can be used with a restricted set of commands only, the
verbose version of list will ([Option]ally) show which modifiers apply.
o The modifier reverse solidus \, to be placed first, prevents
commandalias expansions on the remains of the line, for example
`\echo' will always evaluate the command echo, even if an (com-
mand)alias of the same name exists. commandalias content may itself
contain further command modifiers, including an initial reverse
solidus to prevent further expansions.
o The modifier ignerr indicates that any error generated by the follow-
ing command should be ignored by the state machine and not cause a
program exit with enabled errexit or for the standardized exit cases
in posix mode. ?, one of the INTERNAL VARIABLES, will be set to the
real exit status of the command regardless.
o local will alter the called command to apply changes only temporar-
ily, local to block-scope, and can thus only be used inside of a
defined macro or an account definition. Specifying it implies the
modifier wysh. Local variables will not be inherited by macros
deeper in the call chain, and all local settings will be garbage col-
lected once the local scope is left. To record and unroll changes in
the global scope use the command localopts.
o scope does yet not implement any functionality.
o u does yet not implement any functionality.
o Some commands support the vput modifier: if used, they expect the
name of a variable, which can itself be a variable, i.e., shell ex-
pansion is applied, as their first argument, and will place their
computation result in it instead of the default location (it is usu-
ally written to standard output).
The given name will be tested for being a valid sh(1) variable name,
and may therefore only consist of upper- and lowercase characters,
digits, and the underscore; the hyphen-minus may be used as a non-
portable extension; digits may not be used as first, hyphen-minus may
not be used as last characters. In addition the name may either not
be one of the known INTERNAL VARIABLES, or must otherwise refer to a
writable (non-boolean) value variable. The actual put operation may
fail nonetheless, for example if the variable expects a number argu-
ment only a number will be accepted. Any error during these opera-
tions causes the command as such to fail, and the error number ! will
be set to ^ERR-NOTSUP, the exit status ? should be set to `-1', but
some commands deviate from the latter, which is documented.
o Last, but not least, the modifier wysh can be used for some old and
established commands to choose the new Shell-style argument quoting
rules over the traditional Old-style argument quoting. This modifier
is implied if v15-compat is set to a non-empty value.
Old-style argument quoting
[v15 behaviour may differ] This section documents the traditional and
POSIX standardized style of quoting non-message list arguments to com-
mands which expect this type of arguments: whereas still used by the ma-
jority of such commands, the new Shell-style argument quoting may be
available even for those via wysh, one of the Command modifiers. None-
theless care must be taken, because only new commands have been designed
with all the capabilities of the new quoting rules in mind, which can,
for example generate control characters.
o An argument can be enclosed between paired double-quotes
`"argument"' or single-quotes `'argument''; any whitespace,
shell word expansion, or reverse solidus characters (except as
described next) within the quotes are treated literally as part
of the argument. A double-quote will be treated literally
within single-quotes and vice versa. Inside such a quoted
string the actually used quote character can be used nonethe-
less by escaping it with a reverse solidus `\', as in
`"y\"ou"'.
o An argument that is not enclosed in quotes, as above, can usu-
ally still contain space characters if those spaces are reverse
solidus escaped, as in `you\ are'.
o A reverse solidus outside of the enclosing quotes is discarded
and the following character is treated literally as part of the
argument.
Shell-style argument quoting
sh(1)ell-style, and therefore POSIX standardized, argument parsing and
quoting rules are used by most commands. [v15 behaviour may differ] Most
new commands only support these new rules and are flagged [Only new quot-
ing rules], some elder ones can use them with the command modifier wysh;
in the future only this type of argument quoting will remain.
A command line is parsed from left to right and an input token is com-
pleted whenever an unquoted, otherwise ignored, metacharacter is seen.
Metacharacters are vertical bar |, ampersand &, semicolon ;, as well as
all characters from the variable ifs, and / or space, tabulator, newline.
The additional metacharacters left and right parenthesis (, ) and less-
than and greater-than signs <, > that the sh(1) supports are not used,
and are treated as ordinary characters: for one these characters are a
vivid part of email addresses, and it seems highly unlikely that their
function will become meaningful to S-nail.
Compatibility note: [v15 behaviour may differ] Please note that
even many new-style commands do not yet honour ifs to parse their
arguments: whereas the sh(1)ell is a language with syntactic ele-
ments of clearly defined semantics, S-nail parses entire input
lines and decides on a per-command base what to do with the rest of
the line. This also means that whenever an unknown command is seen
all that S-nail can do is cancellation of the processing of the re-
mains of the line.
It also often depends on an actual subcommand of a multiplexer com-
mand how the rest of the line should be treated, and until v15 we
are not capable to perform this deep inspection of arguments.
Nonetheless, at least the following commands which work with posi-
tional parameters fully support ifs for an almost shell-compatible
field splitting: call, call_if, read, vpospar, xcall.
Any unquoted number sign `#' at the beginning of a new token starts a
comment that extends to the end of the line, and therefore ends argument
processing. An unquoted dollar sign `$' will cause variable expansion of
the given name, which must be a valid sh(1)ell-style variable name (see
vput): INTERNAL VARIABLES as well as ENVIRONMENT (shell) variables can be
accessed through this mechanism, brace enclosing the name is supported
(i.e., to subdivide a token).
Whereas the metacharacters space, tabulator, newline only complete an in-
put token, vertical bar |, ampersand & and semicolon ; also act as con-
trol operators and perform control functions. For now supported is semi-
colon ;, which terminates a single command, therefore sequencing the com-
mand line and making the remainder of the line a subject to reevaluation.
With sequencing, multiple command argument types and quoting rules may
therefore apply to a single line, which can become problematic before
v15: e.g., the first of the following will cause surprising results.
? echo one; set verbose; echo verbose=$verbose.
? echo one; wysh set verbose; echo verbose=$verbose.
Quoting is a mechanism that will remove the special meaning of metachar-
acters and reserved words, and will prevent expansion. There are four
quoting mechanisms: the escape character, single-quotes, double-quotes
and dollar-single-quotes:
o The literal value of any character can be preserved by preced-
ing it with the escape character reverse solidus `\'.
o Arguments which are enclosed in `'single-quotes'' retain their
literal value. A single-quote cannot occur within single-
quotes.
o The literal value of all characters enclosed in `"double-
quotes"' is retained, with the exception of dollar sign `$',
which will cause variable expansion, as above, backquote (grave
accent) ``', (which not yet means anything special), reverse
solidus `\', which will escape any of the characters dollar
sign `$' (to prevent variable expansion), backquote (grave ac-
cent) ``', double-quote `"' (to prevent ending the quote) and
reverse solidus `\' (to prevent escaping, i.e., to embed a re-
verse solidus character as-is), but has no special meaning oth-
erwise.
o Arguments enclosed in `$'dollar-single-quotes'' extend normal
single quotes in that reverse solidus escape sequences are ex-
panded as follows:
`\a' bell control character (ASCII and ISO-10646 BEL).
`\b' backspace control character (ASCII and ISO-10646 BS).
`\E' escape control character (ASCII and ISO-10646 ESC).
`\e' the same.
`\f' form feed control character (ASCII and ISO-10646 FF).
`\n' line feed control character (ASCII and ISO-10646 LF).
`\r' carriage return control character (ASCII and ISO-10646
CR).
`\t' horizontal tabulator control character (ASCII and
ISO-10646 HT).
`\v' vertical tabulator control character (ASCII and
ISO-10646 VT).
`\\' emits a reverse solidus character.
`\'' single quote.
`\"' double quote (escaping is optional).
`\NNN' eight-bit byte with the octal value `NNN' (one to three
octal digits), optionally prefixed by an additional
`0'. A 0 byte will suppress further output for the
quoted argument.
`\xHH' eight-bit byte with the hexadecimal value `HH' (one or
two hexadecimal characters, no prefix, see vexpr). A 0
byte will suppress further output for the quoted argu-
ment.
`\UHHHHHHHH'
the Unicode / ISO-10646 character with the hexadecimal
codepoint value `HHHHHHHH' (one to eight hexadecimal
characters) -- note that Unicode defines the maximum
codepoint ever to be supported as `0x10FFFF' (in planes
of `0xFFFF' characters each). This escape is only sup-
ported in locales that support Unicode (see Character
sets), in other cases the sequence will remain unex-
panded unless the given code point is ASCII compatible
or (if the [Option]al character set conversion is
available) can be represented in the current locale.
The character NUL will suppress further output for the
quoted argument.
`\uHHHH'
Identical to `\UHHHHHHHH' except it takes only one to
four hexadecimal characters.
`\cX' Emits the non-printable (ASCII and compatible) C0 con-
trol codes 0 (NUL) to 31 (US), and 127 (DEL). Print-
able representations of ASCII control codes can be cre-
ated by mapping them to a different, visible part of
the ASCII character set. Adding the number 64 achieves
this for the codes 0 to 31, here 7 (BEL): `7 + 64 = 71
= G'. The real operation is a bitwise logical XOR with
64 (bit 7 set, see vexpr), thus also covering code 127
(DEL), which is mapped to 63 (question mark):
`? vexpr ^ 127 64'.
Whereas historically circumflex notation has often been
used for visualization purposes of control codes, as in
`^G', the reverse solidus notation has been standard-
ized: `\cG'. Some control codes also have standardized
(ISO-10646, ISO C) aliases, as shown above (`\a', `\n',
`\t' etc) : whenever such an alias exists it will be
used for display purposes. The control code NUL
(`\c@', a non-standard extension) will suppress further
output for the remains of the token (which may extend
beyond the current quote), or, depending on the con-
text, the remains of all arguments for the current com-
mand.
`\$NAME'
Non-standard extension: expand the given variable name,
as above. Brace enclosing the name is supported.
`\`{command}'
Not yet supported, just to raise awareness: Non-stan-
dard extension.
Caveats:
? echo 'Quotes '${HOME}' and 'tokens" differ!"# no comment
? echo Quotes ${HOME} and tokens differ! # comment
? echo Don"'"t you worry$'\x21' The sun shines on us. $'\u263A'
Message list arguments
Many commands operate on message list specifications, as documented in
Specifying messages. The argument input is first split into individual
tokens via Shell-style argument quoting, which are then interpreted as
the mentioned specifications. If no explicit message list has been spec-
ified, many commands will search for and use the next message forward
that satisfies the commands' requirements, and if there are no messages
forward of the current message, the search proceeds backwards; if there
are no good messages at all to be found, an error message is shown and
the command is aborted. The verbose output of the command list will in-
dicate whether a command searches for a default message, or not.
Raw data arguments for codec commands
A special set of commands, which all have the string "codec" in their
name, like addrcodec, shcodec, urlcodec, take raw string data as input,
which means that the content of the command input line is passed com-
pletely unexpanded and otherwise unchanged: like this the effect of the
actual codec is visible without any noise of possible shell quoting rules
etc., i.e., the user can input one-to-one the desired or questionable
data. To gain a level of expansion, the entire command line can be
evaluated first, for example
? vput shcodec res encode /usr/Schones Wetter/heute.txt
? echo $res
$'/usr/Sch\u00F6nes Wetter/heute.txt'
? shcodec d $res
$'/usr/Sch\u00F6nes Wetter/heute.txt'
? eval shcodec d $res
/usr/Schones Wetter/heute.txt
Filename transformations
Filenames, where expected, and unless documented otherwise, are subse-
quently subject to the following filename transformations, in sequence:
o If the given name is a registered shortcut, it will be replaced
with the expanded shortcut. This step is mostly taken for
folders only.
o The filename is matched against the following patterns or
strings. But for plus +file folder expansion this step is
mostly taken for folders only.
# (Number sign) is expanded to the previous file.
% (Percent sign) is replaced by the invoking user's pri-
mary system mailbox, which either is the (itself expand-
able) inbox if that is set, the standardized absolute
pathname indicated by MAIL if that is set, or a built-in
compile-time default otherwise. When opening a folder
the used name is actively checked for being a primary
mailbox, first against inbox, then against MAIL.
%user Expands to the primary system mailbox of user (and never
the value of inbox, regardless of its actual setting).
& (Ampersand) is replaced with the invoking user's sec-
ondary mailbox, the MBOX.
+file Refers to a file in the folder directory (if that vari-
able is set).
%:filespec Expands to the same value as filespec, but has spe-
cial meaning when used with, for example, the command
folder: the file will be treated as a primary system
mailbox by, among others, the mbox and save commands,
meaning that messages that have been read in the current
session will be moved to the MBOX mailbox instead of
simply being flagged as read.
o Meta expansions may be applied to the resulting filename, as
allowed by the operation and applicable to the resulting access
protocol (also see On URL syntax and credential lookup). For
the file-protocol, a leading tilde `~' character will be re-
placed by the expansion of HOME, except when followed by a
valid user name, in which case the home directory of the given
user is used instead.
A shell expansion as if specified in double-quotes (see
Shell-style argument quoting) may be applied, so that any oc-
currence of `$VARIABLE' (or `${VARIABLE}') will be replaced by
the expansion of the variable, if possible; INTERNAL VARIABLES
as well as ENVIRONMENT (shell) variables can be accessed
through this mechanism.
Shell pathname wildcard pattern expansions (glob(7)) may be ap-
plied as documented. If the fully expanded filename results in
multiple pathnames and the command is expecting only one file,
an error results.
In interactive context, in order to allow simple value accep-
tance (via "ENTER"), arguments will usually be displayed in a
properly quoted form, so a file `diet\ is \curd.txt' may be
displayed as `'diet\ is \curd.txt''.
Commands
The following commands are available:
! Executes the SHELL command which follows, replacing unescaped
exclamation marks with the previously executed command if the
internal variable bang is set. This command supports vput as
documented in Command modifiers, and manages the error number
!. A 0 or positive exit status ? reflects the exit status of
the command, negative ones that an error happened before the
command was executed, or that the program did not exit cleanly,
but maybe due to a signal: the error number is ^ERR-CHILD,
then.
In conjunction with the vput modifier the following special
cases exist: a negative exit status occurs if the collected
data could not be stored in the given variable, which is a
^ERR-NOTSUP error that should otherwise not occur.
^ERR-CANCELED indicates that no temporary file could be created
to collect the command output at first glance. In case of
catchable out-of-memory situations ^ERR-NOMEM will occur and
S-nail will try to store the empty string, just like with all
other detected error conditions.
# The comment-command causes the entire line to be ignored.
Note: this really is a normal command which' purpose is to dis-
card its arguments, not a "comment-start" indicating special
character, which means that for example trailing comments on a
line are not possible (except for commands which use
Shell-style argument quoting).
+ Goes to the next message in sequence and types it (like
"ENTER").
- Display the preceding message, or the n'th previous message if
given a numeric argument n.
= Shows the message number of the current message (the "dot")
when used without arguments, that of the given list otherwise.
Output numbers will be separated from each other with the first
character of ifs, and followed by the first character of if-ws,
if that is not empty and not identical to the first. If that
results in no separation at all a space character is used.
This command supports vput (see Command modifiers), and manages
the error number !.
? [Option] Show a brief summary of commands. [Option] Given an
argument a synopsis for the command in question is shown in-
stead; commands can be abbreviated in general and this command
can be used to see the full expansion of an abbreviation in-
cluding the synopsis, try, for example `?h', `?hel' and `?help'
and see how the output changes. To avoid that aliases are re-
solved the modifier \ can be prepended to the argument, but
note it must be quoted. This mode also supports a more verbose
output, which will provide the information documented for list.
| A synonym for the pipe command.
account, unaccount
(ac, una) Creates, selects or lists (an) account(s). Accounts
are special incarnations of defined macros and group commands
and variable settings which together usually arrange the envi-
ronment for the purpose of creating an email account. Differ-
ent to normal macros settings which are covered by localopts -
here by default enabled! - will not be reverted before the
account is changed again. The special account `null' (case-in-
sensitive) always exists, and all but it can be deleted by the
latter command, and in one operation with the special name `*'.
Also for all but it a possibly set on-account-cleanup hook is
called once they are left, also for program exit.
Without arguments a listing of all defined accounts is shown.
With one argument the given account is activated: the system
inbox of that account will be activated (as via folder), a pos-
sibly installed folder-hook will be run, and the internal vari-
able account will be updated. The two argument form behaves
identical to defining a macro as via define. Important set-
tings for accounts include folder, from, hostname, inbox, mta,
password and user (On URL syntax and credential lookup), as
well as things like tls-config-pairs (Encrypted network
communication), and protocol specifics like imap-auth,
pop3-auth, smtp-auth.
account myisp {
set folder=~/mail inbox=+syste.mbox record=+sent.mbox
set from='(My Name) myname@myisp.example'
set mta=smtp://mylogin@smtp.myisp.example
}
addrcodec
Perform email address codec transformations on raw-data argu-
ment, rather according to email standards (RFC 5322; [v15 be-
haviour may differ] will furtherly improve). Supports vput
(see Command modifiers), and manages the error number !. The
first argument must be either [+[+[+]]]e[ncode], d[ecode],
s[kin] or skinl[ist] and specifies the operation to perform on
the rest of the line.
Decoding will show how a standard-compliant MUA will display
the given argument, which should be an email address. Please
be aware that most MUAs have difficulties with the address
standards, and vary wildly when (comments) in parenthesis,
"double-quoted" strings, or quoted-pairs, as below, become in-
volved. [v15 behaviour may differ] S-nail currently does not
perform decoding when displaying addresses.
Skinning is identical to decoding but only outputs the plain
address, without any string, comment etc. components. Another
difference is that it may fail with the error number ! set to
^ERR-INVAL if decoding fails to find a(n) (valid) email ad-
dress, in which case the unmodified input will be output again.
skinlist first performs a skin operation, and thereafter checks
a valid address for whether it is a registered mailing list
(see mlist and mlsubscribe), eventually reporting that state in
the error number ! as ^ERR-EXIST. (This state could later be-
come overwritten by an I/O error, though.)
Encoding supports four different modes, lesser automated ver-
sions can be chosen by prefixing one, two or three plus signs:
the standard imposes a special meaning on some characters,
which thus have to be transformed to so-called quoted-pairs by
pairing them with a reverse solidus `\' in order to remove the
special meaning; this might change interpretation of the entire
argument from what has been desired, however! Specify one plus
sign to remark that parenthesis shall be left alone, two for
not turning double quotation marks into quoted-pairs, and three
for also leaving any user-specified reverse solidus alone. The
result will always be valid, if a successful exit status is re-
ported ([v15 behaviour may differ] the current parser fails
this assertion for some constructs). [v15 behaviour may dif-
fer] Addresses need to be specified in between angle brackets
`<', `>' if the construct becomes more difficult, otherwise the
current parser will fail; it is not smart enough to guess
right.
? addrc enc "Hey, you",<diet@exam.ple>\ out\ there
"\"Hey, you\", \\ out\\ there" <diet@exam.ple>
? addrc d "\"Hey, you\", \\ out\\ there" <diet@exam.ple>
"Hey, you", \ out\ there <diet@exam.ple>
? addrc s "\"Hey, you\", \\ out\\ there" <diet@exam.ple>
diet@exam.ple
alias, unalias
[Only new quoting rules](a, una) Define or list, and remove,
respectively, address aliases, which are a method of creating
personal distribution lists that map a single name to none to
multiple receivers, to be expanded after Compose mode is left;
the expansion correlates with metoo. The latter command re-
moves all given aliases, the special name asterisk `*' will re-
move all existing aliases. When used without arguments the
former shows a list of all currently known aliases, with one
argument only the target(s) of the given one. When given two
arguments, hyphen-minus `-' being the first, the target(s) of
the second is/are expanded recursively.
In all other cases the given alias is newly defined, or will be
appended to: arguments must either be themselves valid alias
names, or any other address type (see On sending mail, and non-
interactive mode). Recursive expansion of aliases can be pre-
vented by prefixing the desired argument with the modifier re-
verse solidus \. A valid alias name conforms to mta-aliases
syntax, but follow-up characters can also be the number sign
`#', colon `:', commercial at `@,' exclamation mark `!', period
`.' as well as "any character that has the high bit set". The
dollar sign `$' may be the last character. The number sign `#'
may need Shell-style argument quoting.
[v15 behaviour may differ] Unfortunately the colon is currently
not supported, as it interferes with normal address parsing
rules. [v15 behaviour may differ] Such high bit characters
will likely cause warnings at the moment for the same reasons
why colon is unsupported; also, in the future locale dependent
character set validity checks will be performed.
? alias cohorts bill jkf mark kridle@ucbcory ~/cohorts.mbox
? alias mark mark@exam.ple
? set mta-aliases=/etc/aliases
alternates, unalternates
[Only new quoting rules] (alt) Manage a list of alternate ad-
dresses or names of the active user, members of which will be
removed from recipient lists (except one). There is a set of
implicit alternates which is formed of the values of LOGNAME,
from, sender and reply-to. from will not be used if sender is
set. The latter command removes the given list of alternates,
the special name `*' will discard all existing alternate names.
The former command manages the error number !. It shows the
current set of alternates when used without arguments; in this
mode only it also supports vput (see Command modifiers). Oth-
erwise the given arguments (after being checked for validity)
are appended to the list of alternate names; in posix mode they
replace that list instead.
answered, unanswered
Take a message lists and mark each message as (not) having been
answered. Messages will be marked answered when being replyd
to automatically if the markanswered variable is set. See the
section Message states.
bind, unbind
[Option][Only new quoting rules] The bind command extends the
MLE (see On terminal control and line editor) with freely con-
figurable key bindings. The latter command removes from the
given context the given key binding, both of which may be spec-
ified as a wildcard `*', so that `unbind * *' will remove all
bindings of all contexts. Due to initialization order unbind-
ing will not work for built-in key bindings upon program
startup, however: please use line-editor-no-defaults for this
purpose instead.
With zero arguments, or with a context name the former command
shows all key bindings (of the given context; an asterisk `*'
will iterate over all contexts); a more verbose listing will be
produced if either of debug or verbose are set. With two or
more arguments a specific binding is shown, or (re)established:
the first argument is the context to which the binding shall
apply, the second argument is a comma-separated list of the
"keys" which form the binding. Further arguments will be
joined to form the expansion, and cause the binding to be cre-
ated or updated. To indicate that a binding shall not be auto-
committed, but that the expansion shall instead be furtherly
editable by the user, a commercial at `@' (that will be re-
moved) can be placed last in the expansion, from which leading
and trailing whitespace will finally be removed. Reverse
solidus cannot be used as the last character of expansion. An
empty expansion will be rejected.
Contexts define when a binding applies, i.e., a binding will
not be seen unless the context for which it is defined for is
currently active. This is not true for the shared binding
`base', which is the foundation for all other bindings and as
such always applies, its bindings, however, only apply secon-
darily. The available contexts are the shared `base', the
`default' context which is used in all not otherwise documented
situations, and `compose', which applies only to Compose mode.
Bindings are specified as a comma-separated list of byte-se-
quences, where each list entry corresponds to one "key"
(press). Byte sequence boundaries will be forcefully termi-
nated after bind-inter-byte-timeout milliseconds, whereas key
sequences can be timed out via bind-inter-key-timeout. A list
entry may, indicated by a leading colon character `:', also re-
fer to the name of a terminal capability; several dozen names
are compiled in and may be specified either by their
terminfo(5), or, if existing, by their termcap(5) name, regard-
less of the actually used [Option]al terminal control library.
But any capability may be used, as long as the name is resolv-
able by the [Option]al control library, or was defined via the
internal variable termcap. Input sequences are not case-nor-
malized, an exact match is required to update or remove a bind-
ing. It is advisable to use an initial escape or other control
character (like `\cA') for user (as opposed to purely terminal
capability based) bindings in order to avoid ambiguities; it
also reduces search time. Examples:
? bind base a,b echo one
? bind base $'\E',d mle-snarf-word-fwd # Esc(ape)
? bind base $'\E',$'\c?' mle-snarf-word-bwd # Esc,Delete
? bind default $'\cA',:khome,w 'echo Editable binding@'
? bind default a,b,c rm -irf / @ # Also editable
? bind default :kf1 File %
? bind compose :kf1 ~v
Note that the entire comma-separated list is first parsed
(over) as a shell-token with whitespace as the field separator,
then parsed and expanded for real with comma as the field sepa-
rator, therefore whitespace needs to be properly quoted, see
Shell-style argument quoting. Using Unicode reverse solidus
escape sequences renders a binding defunctional if the locale
does not support Unicode (see Character sets), and using termi-
nal capabilities does so if no (corresponding) terminal control
support is (currently) available. Adding, deleting or modify-
ing a key binding invalidates the internal prebuilt lookup
tree, it will be recreated as necessary: this process will be
visualized in most verbose as well as in debug mode.
The following terminal capability names are built-in and can be
used in terminfo(5) or (if available) the two-letter termcap(5)
notation. See the respective manual for a list of capabili-
ties. The program infocmp(1) can be used to show all the capa-
bilities of TERM or the given terminal type; using the -x flag
will also show supported (non-standard) extensions.
kbs or kb Backspace.
kdch1 or kD Delete character.
kDC or *4 -- shifted variant.
kel or kE Clear to end of line.
kext or @9 Exit.
kich1 or kI Insert character.
kIC or #3 -- shifted variant.
khome or kh Home.
kHOM or #2 -- shifted variant.
kend or @7 End.
knp or kN Next page.
kpp or kP Previous page.
kcub1 or kl Left cursor (with more modifiers: see below).
kLFT or #4 -- shifted variant.
kcuf1 or kr Right cursor (ditto).
kRIT or %i -- shifted variant.
kcud1 or kd Down cursor (ditto).
kDN -- shifted variant (only terminfo).
kcuu1 or ku Up cursor (ditto).
kUP -- shifted variant (only terminfo).
kf0 or k0 Function key 0. Add one for each function key
up to kf9 and k9, respectively.
kf10 or k; Function key 10.
kf11 or F1 Function key 11. Add one for each function key
up to kf19 and F9, respectively.
Some terminals support key-modifier combination extensions,
e.g., `Alt+Shift+xy'. For example, the delete key, kdch1: in
its shifted variant, the name is mutated to kDC, then a number
is appended for the states `Alt' (kDC3), `Shift+Alt' (kDC4),
`Control' (kDC5), `Shift+Control' (kDC6), `Alt+Control' (kDC7),
finally `Shift+Alt+Control' (kDC8). The same for the left cur-
sor key, kcub1: KLFT, KLFT3, KLFT4, KLFT5, KLFT6, KLFT7, KLFT8.
call [Only new quoting rules] Calls the given macro, which must have
been created via define (see there for more), otherwise an
^ERR-NOENT error occurs. Calling macros recursively will at
some time excess the stack size limit, causing a hard program
abortion; if recursively calling a macro is the last command of
the current macro, consider to use the command xcall, which
will first release all resources of the current macro before
replacing the current macro with the called one.
call_if Identical to call if the given macro has been created via
define, but does not fail nor warn if the macro does not exist.
cd Synonym for chdir.
certsave [Option] Only applicable to S/MIME signed messages. Takes an
optional message list and a filename and saves the certificates
contained within the message signatures to the named file in
both human-readable and PEM format. The certificates can later
be used to send encrypted messages to the respective message
senders by setting smime-encrypt-USER@HOST variables.
charsetalias, uncharsetalias
[Only new quoting rules] Manage alias mappings for (conversion
of) Character sets. Alias processing is not performed for
INTERNAL VARIABLES, for example charset-8bit, and mappings are
ineffective if character set conversion is not available
(features does not announce `,+iconv,'). Expansion happens re-
cursively for cases where aliases point to other aliases
(built-in loop limit: 8).
The latter command deletes all aliases given as arguments, or
all at once when given the asterisk `*'. The former shows the
list of all currently defined aliases if used without argu-
ments, or the target of the given single argument; when given
two arguments, hyphen-minus `-' being the first, the second is
instead expanded recursively. In all other cases the given ar-
guments are treated as pairs of character sets and their de-
sired target alias name, creating new or updating already ex-
isting aliases.
chdir [Only new quoting rules](ch) Change the working directory to
HOME or the given argument. Synonym for cd.
collapse, uncollapse
Only applicable to `thread'ed sort mode. Takes a message list
and makes all replies to these messages invisible in header
summaries, except for `new' messages and the "dot". Also when
a message with collapsed replies is displayed, all of these are
automatically uncollapsed. The latter command undoes collaps-
ing.
colour, uncolour
[Option][Only new quoting rules] Manage colour mappings of and
for a Coloured display. Without arguments the former shows all
currently defined mappings. Otherwise a colour type is ex-
pected (case-insensitively), it must be one of `256' for
256-colour terminals, `8', `ansi' or `iso' for the standard
8-colour ANSI / ISO 6429 colour palette, and `1' or `mono' for
monochrome terminals, which only support (some) font at-
tributes. Without further arguments the list of all currently
defined mappings of the given type is shown (here the special
`all' or `*' also show all currently defined mappings).
Otherwise the second argument defines the mappable slot, the
third argument a (comma-separated list of) colour and font at-
tribute specification(s), and the optionally supported fourth
argument can be used to specify a precondition: if conditioned
mappings exist they are tested in (creation) order unless a
(case-insensitive) match has been found, and the default map-
ping (if any has been established) will only be chosen as a
last resort. The types of available preconditions depend on
the mappable slot, the following of which exist:
Mappings prefixed with `mle-' are used for the [Option]al
built-in Mailx-Line-Editor (MLE, see On terminal control and
line editor) and do not support preconditions.
mle-position This mapping is used for the position indicator
that is visible when a line cannot be fully dis-
played on the screen.
mle-prompt Used for the prompt.
mle-error Used for the occasionally appearing error indi-
cator that is joined onto prompt. [v15 behav-
iour may differ] Also used for error messages
written on standard error .
Mappings prefixed with `sum-' are used in header summaries, and
they all understand the preconditions `dot' (the current mes-
sage) and `older' for elder messages (only honoured in conjunc-
tion with datefield-markout-older).
sum-dotmark This mapping is used for the "dotmark" that can
be created with the `%>' or `%<' formats of the
variable headline.
sum-header For the complete header summary line except the
"dotmark" and the thread structure.
sum-thread For the thread structure which can be created
with the `%i' format of the variable headline.
Mappings prefixed with `view-' are used when displaying mes-
sages.
view-from_ This mapping is used for so-called `From_'
lines, which are MBOX file format specific
header lines (also see mbox-rfc4155).
view-header For header lines. A comma-separated list of
headers to which the mapping applies may be
given as a precondition; if the [Option]al regu-
lar expression support is available then if any
of the magic regular expression characters is
seen the precondition will be evaluated as (an
extended) one.
view-msginfo For the introductional message info line.
view-partinfo For MIME part info lines.
The following (case-insensitive) colour definitions and font
attributes are understood, multiple of which can be specified
in a comma-separated list:
ft= a font attribute: `bold', `reverse' or `underline'. It is
possible (and often applicable) to specify multiple font
attributes for a single mapping.
fg= foreground colour attribute, in order (numbers 0 - 7)
`black', `red', `green', `brown', `blue', `magenta',
`cyan' or `white'. To specify a 256-colour mode a decimal
number colour specification in the range 0 to 255, inclu-
sive, is supported, and interpreted as follows:
0 - 7 the standard ISO 6429 colours, as above.
8 - 15 high intensity variants of the standard
colours.
16 - 231 216 colours in tuples of 6.
232 - 255 grayscale from black to white in 24 steps.
#!/bin/sh -
fg() { printf "\033[38;5;${1}m($1)"; }
bg() { printf "\033[48;5;${1}m($1)"; }
i=0
while [ $i -lt 256 ]; do fg $i; i=$(($i + 1)); done
printf "\033[0m\n"
i=0
while [ $i -lt 256 ]; do bg $i; i=$(($i + 1)); done
printf "\033[0m\n"
bg= background colour attribute (see fg= for possible values).
The command uncolour will remove for the given colour type (the
special type `*' selects all) the given mapping; if the op-
tional precondition argument is given only the exact tuple of
mapping and precondition is removed. The special name `*' will
remove all mappings (no precondition allowed), thus `uncolour *
*' will remove all established mappings.
commandalias, uncommandalias
[Only new quoting rules] Define or list, and remove, respec-
tively, command aliases. An (command)alias can be used every-
where a normal command can be used, but always takes prece-
dence: any arguments that are given to the command alias are
joined onto the alias expansion, and the resulting string forms
the command line that is, in effect, executed. The latter com-
mand removes all given aliases, the special name asterisk `*'
will remove all existing aliases. When used without arguments
the former shows a list of all currently known aliases, with
one argument only the expansion of the given one.
With two or more arguments a command alias is defined or up-
dated: the first argument is the name under which the remaining
command line should be accessible, the content of which can be
just about anything. An alias may itself expand to another
alias, but to avoid expansion loops further expansion will be
prevented if an alias refers to itself or if an expansion depth
limit is reached. Explicit expansion prevention is available
via reverse solidus \, one of the Command modifiers.
? commandalias xx
s-nail: `commandalias': no such alias: xx
? commandalias xx echo hello,
? commandalias xx
commandalias xx 'echo hello,'
? xx
hello,
? xx world
hello, world
Copy (C) Similar to copy, but copy the messages to a file named af-
ter the local part of the sender of the first message instead
of taking a filename argument; outfolder is inspected to decide
on the actual storage location.
copy (c) Copy messages to the named file and do not mark them as be-
ing saved; otherwise identical to save.
csop [Only new quoting rules] A multiplexer command which provides
C-style string operations on 8-bit bytes without a notion of
locale settings and character sets, effectively assuming ASCII
data. For numeric and other operations refer to vexpr. vput,
one of the Command modifiers, is supported. The error result
is `-1' for usage errors and numeric results, the empty string
otherwise; missing data errors, as for unsuccessful searches,
result in the ! error number being set to ^ERR-NODATA. Where
the question mark `?' modifier suffix is supported, a case-in-
sensitive (ASCII mapping) operation mode is supported; the key-
word `case' is optional so that `find?' and `find?case' are
identical.
length Queries the length of the given argument.
hash, hash32 Calculates a hash value of the given argument.
The latter will return a 32-bit result regardless of
host environment. `?' modifier suffix is supported.
These use Chris Torek's hash algorithm, the resulting
hash value is bit mixed as shown by Bret Mulvey.
find Search for the second in the first argument. Shows
the resulting 0-based offset shall it have been
found. `?' modifier suffix is supported.
substring Creates a substring of its first argument. The op-
tional second argument is the 0-based starting off-
set, a negative one counts from the end; the optional
third argument specifies the length of the desired
result, a negative length leaves off the given number
of bytes at the end of the original string; by de-
fault the entire string is used. This operation
tries to work around faulty arguments (set verbose
for error logs), but reports them via the error num-
ber ! as ^ERR-OVERFLOW.
trim Trim away whitespace characters from both ends of the
argument.
trim-front Trim away whitespace characters from the begin of
the argument.
trim-end Trim away whitespace characters from the end of the
argument.
cwd Show the name of the current working directory, as reported by
getcwd(3). Supports vput (see Command modifiers). The return
status is tracked via ?.
Decrypt [Option] For unencrypted messages this command is identical to
Copy; Encrypted messages are first decrypted, if possible, and
then copied.
decrypt [Option] For unencrypted messages this command is identical to
copy; Encrypted messages are first decrypted, if possible, and
then copied.
define, undefine
The latter command deletes the given macro, the special name
`*' will discard all existing macros. Deletion of (a) macro(s)
can be performed from within running (a) macro(s), including
self-deletion. Without arguments the former command prints the
current list of macros, including their content, otherwise it
defines a macro, replacing an existing one of the same name as
applicable.
A defined macro can be invoked explicitly by using the call,
call_if and xcall commands, or implicitly if a macro hook is
triggered, for example a folder-hook. Execution of a macro
body can be stopped from within by calling return.
Temporary macro block-scope variables can be created or deleted
with the local command modifier in conjunction with the com-
mands set and unset, respectively. To enforce unrolling of
changes made to (global) INTERNAL VARIABLES the command
localopts can be used instead; its covered scope depends on how
(i.e., "as what": normal macro, folder hook, hook, account
switch) the macro is invoked.
Inside a called macro, the given positional parameters are im-
plicitly local to the macro's scope, and may be accessed via
the variables *, @, # and 1 and any other positive unsigned
decimal number less than or equal to #. Positional parameters
can be shifted, or become completely replaced, removed etc. via
vpospar. A helpful command for numeric computation and string
evaluations is vexpr, csop offers C-style byte string opera-
tions.
define name {
command1
command2
...
commandN
}
define exmac {
echo Parameter 1 of ${#} is ${1}, all: ${*} / ${@}
return 1000 0
}
call exmac Hello macro exmac!
echo ${?}/${!}/${^ERRNAME}
delete, undelete
(d, u) Marks the given message list as being or not being
`deleted', respectively; if no argument has been specified then
the usual search for a visible message is performed, as docu-
mented for Message list arguments, showing only the next input
prompt if the search fails. Deleted messages will neither be
saved in the secondary mailbox MBOX nor will they be available
for most other commands. If the autoprint variable is set, the
new "dot" or the last message restored, respectively, is auto-
matically typed; also see dp, dt.
digmsg [Only new quoting rules] Digging (information out of) messages
is possible through digmsg objects, which can be created for
the given message number; in Compose mode the hyphen-minus `-'
will instead open the message that is being composed. If a hy-
phen-minus is given as the optional third argument then output
will be generated on the standard output channel instead of be-
ing subject to consumption by the readsh (here better than read
or readall) command.
The objects may be removed again by giving the same identifier
used for creation; this step could be omitted: objects will be
automatically closed when the active folder (mailbox) or the
compose mode is left, respectively. In all other use cases the
second argument is an object identifier, and the third and all
following arguments are interpreted as via ~^ (see COMMAND
ESCAPES):
? vput = msgno; digmsg create $msgno
? digmsg $msgno header list; readall x; echon $x
210 Subject From To Message-ID References In-Reply-To
? digmsg $msgno header show Subject;readall x;echon $x
212 Subject
'Hello, world'
? digmsg remove $msgno
discard (di) Identical to ignore. Superseded by the multiplexer
headerpick.
dp, dt Delete the given messages and automatically type the new "dot"
if one exists, regardless of the setting of autoprint.
dotmove Move the "dot" up or down by one message when given `+' or `-'
argument, respectively.
draft, undraft
Take message lists and mark each given message as being draft,
or not being draft, respectively, as documented in the section
Message states.
echo [Only new quoting rules](ec) Print the given strings, equiva-
lent to the shell utility echo(1), that is, Shell-style
argument quoting expansion is performed and, different to the
otherwise identical echon, a trailing newline is echoed. vput
as documented in Command modifiers is supported, and the error
number ! is managed: if data is stored in a variable then the
return value reflects the length of the result string in case
of success and is `-1' on error.
Remarks: this command traditionally (in BSD Mail) also per-
formed Filename transformations, which is standard incompatible
and hard to handle because quoting transformation patterns is
not possible; the subcommand file-expand of vexpr can be used
to expand filenames.
echoerr [Only new quoting rules] Identical to echo, but the message is
written to standard error, and prefixed by log-prefix. Also
see echoerrn. In interactive sessions the [Option]al message
ring queue for errors will be used instead, if available and
vput was not used.
echon [Only new quoting rules] Identical to echo, but does not write
or store a trailing newline.
echoerrn [Only new quoting rules] Identical to echoerr, but does not
write or store a trailing newline.
edit (e) Point the text EDITOR at each message from the given list
in turn. Modified contents are discarded unless the
writebackedited variable is set, and are not used unless the
mailbox can be written to and the editor returns a successful
exit status. visual can be used instead for a more display
oriented editor.
elif Part of the if (see there for more), elif, else, endif condi-
tional -- if the condition of a preceding if was false, check
the following condition and execute the following block if it
evaluates true.
else (el) Part of the if (see there for more), elif, else, endif
conditional -- if none of the conditions of the preceding if
and elif commands was true, the else block is executed.
endif (en) Marks the end of an if (see there for more), elif, else,
endif conditional execution block.
environ [Only new quoting rules] There is a strict separation in be-
tween INTERNAL VARIABLES and the program ENVIRONMENT, which is
inherited by child processes. Some variables of the latter are
however vivid for program operation, their purpose is known,
therefore they have been integrated transparently into handling
of the former, as accessible via set and unset. To integrate
any other environment variable, and/or to export internal vari-
ables into the process environment where they normally are not,
a link needs to become established with this command, for exam-
ple
environ link PERL5LIB TZ
Afterwards changing such variables with set will cause auto-
matic updates of the environment, too. Sufficient system sup-
port provided (it was in BSD as early as 1987, and is standard-
ized since Y2K) removing such variables with unset will remove
them also from the environment, but in any way the knowledge
they ever have been linked will be lost. This implies that
localopts may cause loss of such links.
The subcommand unlink removes an existing link without other-
wise touching variables, the set and unset subcommands are
identical to set and unset, but additionally update the program
environment accordingly; removing a variable breaks any freely
established link.
errors [Option] As console user interfaces at times scroll error mes-
sages by too fast and/or out of scope, data can additionally be
sent to an error queue manageable by this command: show or no
argument will display and clear the queue, clear will only
clear it. As the queue becomes filled with errors-limit en-
tries the eldest entries are being dropped. There are also the
variables ^ERRQUEUE-COUNT and ^ERRQUEUE-EXISTS.
eval [Only new quoting rules] Construct a command by concatenating
the arguments, separated with a single space character, and
then evaluate the result. This command passes through the exit
status ? and error number ! of the evaluated command; also see
call.
define xxx {
echo "xxx arg <$1>"
shift
if $# -gt 0
\xcall xxx "$@"
endif
}
define yyy {
eval "$@ ' ball"
}
call yyy '\call xxx' "b\$'\t'u ' "
call xxx arg <b u>
call xxx arg < >
call xxx arg <ball>
exit (ex or x) Exit from S-nail without changing the active mailbox
and skip any saving of messages in the secondary mailbox MBOX,
as well as a possibly tracked line editor history-file. A pos-
sibly set on-account-cleanup will be invoked, however. The op-
tional status number argument will be passed through to
exit(3). [v15 behaviour may differ] For now it can happen that
the given status will be overwritten, later this will only oc-
cur if a later error needs to be reported onto an otherwise
success indicating status.
File (Fi) Like folder, but open the mailbox read-only.
file (fi) See folder.
filetype, unfiletype
[Only new quoting rules] Define, list, and remove, respec-
tively, file handler hooks, which provide (shell) commands that
enable S-nail to load and save MBOX files from and to files
with the registered file extensions, as shown and described for
folder. The extensions are used case-insensitively, yet the
auto-completion feature of for example folder will only work
case-sensitively. An intermediate temporary file will be used
to store the expanded data. The latter command will remove
hooks for all given extensions, asterisk `*' will remove all
existing handlers.
When used without arguments the former shows a list of all cur-
rently defined file hooks, with one argument the expansion of
the given alias. Otherwise three arguments are expected, the
first specifying the file extension for which the hook is
meant, and the second and third defining the load- and save
commands to deal with the file type, respectively, both of
which must read from standard input and write to standard out-
put. Changing hooks will not affect already opened mailboxes
([v15 behaviour may differ] except below). [v15 behaviour may
differ] For now too much work is done, and files are oftened
read in twice where once would be sufficient: this can cause
problems if a filetype is changed while such a file is opened;
this was already so with the built-in support of .gz etc. in
Heirloom, and will vanish in v15. [v15 behaviour may differ]
For now all handler strings are passed to the SHELL for
evaluation purposes; in the future a `!' prefix to load and
save commands may mean to bypass this shell instance: placing a
leading space will avoid any possible misinterpretations.
? filetype bz2 'bzip2 -dc' 'bzip2 -zc' \
gz 'gzip -dc' 'gzip -c' xz 'xz -dc' 'xz -zc' \
zst 'zstd -dc' 'zstd -19 -zc' \
zst.pgp 'gpg -d | zstd -dc' 'zstd -19 -zc | gpg -e'
? set record=+sent.zst.pgp
flag, unflag
Take message lists and mark the messages as being flagged, or
not being flagged, respectively, for urgent/special attention.
See the section Message states.
Folder (Fold) Like folder, but open the mailbox read-only.
folder (fold) Open a new, or show status information of the current
mailbox. If an argument is given, changes (such as deletions)
will be written out, a new mailbox will be opened, the internal
variables mailbox-resolved and mailbox-display will be updated,
a set according folder-hook is executed, and optionally a sum-
mary of headers is displayed if the variable header is set.
Filename transformations will be applied to the name argument,
and `protocol://' prefixes are, i.e., URL (see On URL syntax
and credential lookup) syntax is understood, as in
`mbox:///tmp/somefolder'. If a protocol prefix is used the
mailbox type is fixated, otherwise opening none-existing
folders uses the protocol defined in newfolders.
For the protocols mbox and file (MBOX database), as well as eml
(electronic mail message [v15 behaviour may differ] read-only)
the list of all registered filetypes is traversed to check
whether hooks shall be used to load (and save) data from (and
to) the given name. Changing hooks will not affect already
opened mailboxes. For example, the following creates hooks for
the gzip(1) compression tool and a combined compressed and en-
crypted format:
? filetype \
gzip 'gzip -dc' 'gzip -c' \
zst.pgp 'gpg -d | zstd -dc' 'zstd -19 -zc | gpg -e'
For historic reasons filetypes provide limited (case-sensitive)
auto-completion capabilities. For example `mbox.gz' will be
found for `? file mbox', provided that corresponding handlers
are installed. It will neither find `mbox.GZ' nor `mbox.Gz'
however, but an explicit `? file mbox.GZ' will find and use the
handler for `gz'. [v15 behaviour may differ] The latter mode
can only be used for MBOX files.
EML files consist of only one mail message, [v15 behaviour may
differ] and can only be opened read-only. When reading MBOX
files tolerant POSIX rules are used by default. Invalid mes-
sage boundaries that can be found quite often in historic MBOX
files will be complained about (even more with debug): in this
case the method described for mbox-rfc4155 can be used to cre-
ate a valid MBOX database from the invalid input.
MBOX databases and EML files will always be protected via file-
region locks (fcntl(2)) during file operations to protect
against concurrent modifications. [Option] An MBOX inbox
(MAIL) or primary system mailbox will also be protected by so-
called dotlock files, the traditional way of mail spool file
locking: for any file `x' a lock file `x.lock' will be created
during the synchronization, in the same directory and with the
same user and group identities as the file of interest -- as
necessary created by an external privileged dotlock helper.
dotlock-disable disables dotlock files. Also see FAQ: Howto
handle stale dotlock files.
[Option] If no protocol has been fixated, and name refers to a
directory with the subdirectories `tmp', `new' and `cur', then
it is treated as a folder in "Maildir" format. The maildir
format stores each message in its own file, and has been de-
signed so that file locking is not necessary when reading or
writing files.
[Option]ally URLs can be used to access network resources, se-
curely via Encrypted network communication, if so supported.
Network communication socket timeouts are configurable via
socket-connect-timeout. All network traffic may be proxied
over a SOCKS server via socks-proxy.
[v15-compat]
protocol://[user[:password]@]host[:port][/path]
[no v15-compat] protocol://[user@]host[:port][/path]
[Option]ally supported network protocols are pop3 (POP3) and
pop3s (POP3 with TLS encrypted transport), imap and imaps. The
[/path] part is valid only for IMAP; there it defaults to
INBOX. Network URLs require a special encoding as documented
in the section On URL syntax and credential lookup.
folders Lists the names of all folders below the given argument or
folder. For file-based protocols LISTER will be used for dis-
play purposes.
Followup, followup
(Compose mode)(F,fo) Similar to Reply, and reply, respectively,
but save the message in a file named after the local part of
the (first) recipient's address, possibly overwriting record,
and honouring outfolder. Also see Copy and Save.
Forward (Compose mode) Similar to forward, but saves the message in a
file named after the local part of the recipient's address (in-
stead of in record).
forward (Compose mode) Take a message list and the address of a recipi-
ent, subject to fullnames, to whom the messages are sent. The
text of the original message is included in the new one, en-
closed by the values of forward-inject-head and
forward-inject-tail. content-description-forwarded-message is
inspected. The list of included headers can be filtered with
the `forward' slot of the white- and blacklisting command
headerpick. Only the first part of a multipart message is in-
cluded but for forward-as-attachment.
This may generate the errors ^ERR-DESTADDRREQ if no receiver
has been specified, or was rejected by expandaddr policy,
^ERR-IO if an I/O error occurs, ^ERR-NOTSUP if a necessary
character set conversion fails, and ^ERR-INVAL for other er-
rors. It can also fail with errors of Specifying messages.
Any error stops processing of further messages.
from (f) Takes a list of message specifications and displays a sum-
mary of their message headers, exactly as via headers, making
the first message of the result the new "dot" (the last message
if showlast is set). An alias of this command is search. Also
see Specifying messages.
Fwd [Obsolete] Alias for Forward.
fwd [Obsolete] Alias for forward.
fwdignore
[Obsolete] Superseded by the multiplexer headerpick.
fwdretain
[Obsolete] Superseded by the multiplexer headerpick.
ghost, unghost
[Obsolete] Replaced by commandalias, uncommandalias.
headerpick, unheaderpick
[Only new quoting rules] Multiplexer command to manage white-
and blacklisting selections of header fields for a variety of
applications. Without arguments the set of contexts that have
settings is displayed. When given arguments, the first argu-
ment is the context to which the command applies, one of (case-
insensitive) `type' for display purposes (for example type),
`save' for selecting which headers shall be stored persistently
when save, copy, move or even decrypting messages (note that
MIME related etc. header fields should not be ignored in order
to not destroy usability of the message in this case),
`forward' for stripping down messages when forwarding message
(has no effect if forward-as-attachment is set), and `top' for
defining user-defined set of fields for the command top.
The current settings of the given context are displayed if it
is the only argument. A second argument denotes the type of
restriction that is to be chosen, it may be (a case-insensitive
prefix of) `retain' or `ignore' for white- and blacklisting
purposes, respectively. Establishing a whitelist suppresses
inspection of the corresponding blacklist.
If no further argument is given the current settings of the
given type will be displayed, otherwise the remaining arguments
specify header fields, which [Option]ally may be given as regu-
lar expressions, to be added to the given type. The special
wildcard field (asterisk, `*') will establish a (fast) short-
hand setting which covers all fields.
The latter command always takes three or more arguments and can
be used to remove selections, i.e., from the given context, the
given type of list, all the given headers will be removed, the
special argument `*' will remove all headers.
headers (h) Show the current group of headers, the size of which de-
pends on the variable screen in interactive mode, and the for-
mat of which can be defined with headline. If a message-speci-
fication is given the group of headers containing the first
message therein is shown and the message at the top of the
screen becomes the new "dot"; the last message is targeted if
showlast is set.
help (hel) A synonym for ?.
history [Option] Without arguments or when given show all history en-
tries are shown (this mode also supports a more verbose out-
put). load will replace the list of entries with the content
of history-file, and save will dump all entries to said file,
replacing former content, and clear will delete all entries.
The argument can also be a signed decimal NUMBER, which will
select and evaluate the respective history entry, and move it
to the top of the history; a negative number is used as an off-
set to the current command so that `-1' will select the last
command, the history top, whereas delete will delete all given
entries (:NUMBER:). Also see On terminal control and line
editor.
hold (ho, also preserve) Takes a message list and marks each message
therein to be saved in the user's system inbox instead of in
the secondary mailbox MBOX. Does not override the delete com-
mand. S-nail deviates from the POSIX standard with this com-
mand, because a next command issued after hold will display the
following message, not the current one.
if (i) Part of the if, elif, else, endif conditional execution
construct -- if the given condition is true then the encapsu-
lated block is executed. The POSIX standard only supports the
(case-insensitive) conditions `r'eceive and `s'end, the remain-
ing are non-portable extensions. [v15 behaviour may differ] In
conjunction with the wysh command prefix(es) Shell-style
argument quoting and more test operators are available.
if receive
commands ...
else
commands ...
endif
Further (case-insensitive) one-argument conditions are
`t'erminal which evaluates to true in interactive terminal ses-
sions (running with standard input or standard output attached
to a terminal, and none of the "quickrun" command line options
-e, -H and -L have been used), as well as any boolean value
(see INTERNAL VARIABLES for textual boolean representations) to
mark an enwrapped block as "never execute" or "always execute".
(Remarks: condition syntax errors skip all branches until
endif.)
[no v15-compat] and without wysh: It is possible to check
INTERNAL VARIABLES as well as ENVIRONMENT variables for exis-
tence or compare their expansion against a user given value or
another variable by using the `$' ("variable next") conditional
trigger character; a variable on the right hand side may be
signalled using the same mechanism. Variable names may be en-
closed in a pair of matching braces. When this mode has been
triggered, several operators are available ([v15-compat] and
wysh: they are always available, and there is no trigger: vari-
ables will have been expanded by the shell-compatible parser
before the if etc. command sees them).
[v15-compat] Two argument conditions. Variables can be tested
for existence and expansion: `-N' will test whether the given
variable exists, so that `-N editalong' will evaluate to true
when editalong is set, whereas `-Z editalong' will if it is
not. `-n "$editalong"' will be true if the variable is set and
expands to a non-empty string, `-z $'\$editalong'' only if the
expansion is empty, whether the variable exists or not. The
remaining conditions take three arguments.
Integer operators treat the arguments on the left and right
hand side of the operator as integral numbers and compare them
arithmetically. It is an error if any of the operands is not a
valid integer, an empty argument (which implies it had been
quoted) is treated as if it were 0. Via the question mark `?'
modifier suffix a saturated operation mode is available where
numbers will linger at the minimum or maximum possible value,
instead of overflowing (or trapping), the keyword `saturated'
is optional, `==?', `==?satu' and `==?saturated' are therefore
identical. Available operators are `-lt' (less than), `-le'
(less than or equal to), `-eq' (equal), `-ne' (not equal),
`-ge' (greater than or equal to), and `-gt' (greater than).
String and regular expression data operators compare the left
and right hand side according to their textual content. Unset
variables are treated as the empty string. Via the question
mark `?' modifier suffix a case-insensitive operation mode is
available, the keyword `case' is optional, `==?' and `==?case'
are identical.
Available string operators are `<' (less than), `<=' (less than
or equal to), `==' (equal), `!=' (not equal), `>=' (greater
than or equal to), `>' (greater than), `=%' (is substring of)
and `!%' (is not substring of). By default these operators
work on bytes and (therefore) do not take into account charac-
ter set specifics. If the case-insensitivity modifier has been
used, case is ignored according to the rules of the US-ASCII
encoding, i.e., bytes are still compared.
When the [Option]al regular expression support is available,
the additional string operators `=~' and `!~' can be used.
They treat the right hand side as an extended regular expres-
sion that is matched according to the active locale (see
Character sets), i.e., character sets should be honoured cor-
rectly.
Conditions can be joined via AND-OR lists (where the AND opera-
tor is `&&' and the OR operator is `||'), which have equal
precedence and will be evaluated with left associativity, thus
using the same syntax that is known for the sh(1). It is also
possible to form groups of conditions and lists by enclosing
them in pairs of brackets `[ ... ]', which may be interlocked
within each other, and also be joined via AND-OR lists.
The results of individual conditions and entire groups may be
modified via unary operators: the unary operator `!' will re-
verse the result.
wysh set v15-compat=yes # with value: automatic "wysh"!
if -N debug;echo *debug* set;else;echo not;endif
if "$ttycharset" == UTF-8 || "$ttycharset" ==?cas UTF8
echo ttycharset is UTF-8, the former case-sensitive!
endif
set t1=one t2=one
if [ "${t1}" == "${t2}" ]
echo These two variables are equal
endif
if "$features" =% ,+regex, && "$TERM" =~?case ^xterm.*
echo ..in an X terminal
endif
if [ [ true ] && [ [ "${debug}" != '' ] || \
[ "$verbose" != '' ] ] ]
echo Noisy, noisy
endif
if true && [ -n "$debug" || -n "${verbose}" ]
echo Left associativity, as is known from the shell
endif
ignore (ig) Identical to discard. Superseded by the multiplexer
headerpick.
list Shows the names of all available commands, in command lookup
order. [Option] In conjunction with a set variable verbose ad-
ditional information will be provided for each command: the ar-
gument type will be indicated, the documentation string will be
shown, and the set of command flags will show up:
``local'' command supports the command modifier local.
``vput'' command supports the command modifier vput.
`*!*' the error number is tracked in !.
`needs-box' whether the command needs an active mailbox, a
folder.
`ok:' indicators whether command is ...
`batch/interactive'
usable in interactive or batch mode
(-#).
`send-mode' usable in send mode.
`subprocess' allowed to be used when running in a
subprocess instance, for example
from within a macro that is called
via on-compose-splice.
`not ok:' indicators whether command is not ...
`compose mode' available in Compose mode.
`startup' available during program startup,
like in Resource files.
`gabby' The command produces history-gabby history en-
tries.
localopts
Enforce change localization of environ (linked) ENVIRONMENT as
well as (global) INTERNAL VARIABLES, meaning that their state
will be reverted to the former one once the "covered scope" is
left. Just like the command modifier local, which provides
block-scope localization for some commands (instead), it can
only be used inside of macro definition blocks introduced by
account or define. The covered scope of an account is left
once a different account is activated, and some macros, notably
folder-hooks, use their own specific notion of covered scope,
here it will be extended until the folder is left again.
This setting stacks up: i.e., if `macro1' enables change local-
ization and calls `macro2', which explicitly resets localiza-
tion, then any value changes within `macro2' will still be re-
verted when the scope of `macro1' is left. (Caveats: if in
this example `macro2' changes to a different account which sets
some variables that are already covered by localizations, their
scope will be extended, and in fact leaving the account will
(thus) restore settings in (likely) global scope which actually
were defined in a local, macro private context!)
This command takes one or two arguments, the optional first one
specifies an attribute that may be one of scope, which refers
to the current scope and is thus the default, call, which
causes any macro that is being called to be started with local-
ization enabled by default, as well as call-fixate, which (if
enabled) disallows any called macro to turn off localization:
like this it can be ensured that once the current scope regains
control, any changes made in deeper levels have been reverted.
The latter two are mutually exclusive, and neither affects
xcall. The (second) argument is interpreted as a boolean
(string, see INTERNAL VARIABLES) and states whether the given
attribute shall be turned on or off.
define temporary_settings {
set possibly_global_option1
localopts on
set localized_option1
set localized_option2
localopts scope off
set possibly_global_option2
}
Lfollowup, Lreply
(Compose mode) Reply to messages that come in via known (mlist)
or subscribed (mlsubscribe) mailing lists, or pretend to do so
(see Mailing lists): on top of the usual followup and reply,
respectively, functionality this will actively resort and even
remove message recipients in order to generate a message that
is supposed to be sent to a mailing list. For example it will
also implicitly generate a `Mail-Followup-To:' header if that
seems useful, regardless of the setting of the variable
followup-to. For more documentation please refer to On sending
mail, and non-interactive mode.
This may generate the errors ^ERR-DESTADDRREQ if no receiver
has been specified, ^ERR-PERM if some addressees where rejected
by expandaddr, ^ERR-IO if an I/O error occurs, ^ERR-NOTSUP if a
necessary character set conversion fails, and ^ERR-INVAL for
other errors. It can also fail with errors of Specifying
messages. Occurrence of some of the errors depend on the value
of expandaddr. Any error stops processing of further messages.
Mail (Compose mode) Similar to mail, but saves the message in a file
named after the local part of the first recipient's address
(instead of in record).
mail (Compose mode)(m) Takes a (list of) recipient address(es) as
(an) argument(s), or asks on standard input if none were given;
then collects the remaining mail content and sends it out. Un-
less the internal variable fullnames is set recipient addresses
will be stripped from comments, names etc. For more documenta-
tion please refer to On sending mail, and non-interactive mode.
This may generate the errors ^ERR-DESTADDRREQ if no receiver
has been specified, ^ERR-PERM if some addressees where rejected
by expandaddr, ^ERR-NOTSUP if multiple messages have been spec-
ified, ^ERR-IO if an I/O error occurs, ^ERR-NOTSUP if a neces-
sary character set conversion fails, and ^ERR-INVAL for other
errors. It can also fail with errors of Specifying messages.
Occurrence of some of the errors depend on the value of
expandaddr.
mailcap [Option] When used without arguments or if show has been given
the content of The Mailcap files cache is shown, (re-)initial-
izing it first (as necessary. If the argument is load then the
cache will only be (re-)initialized, and clear will remove its
contents. Note that S-nail will try to load the files only
once, use `mailcap clear' to unlock further attempts. Loading
and parsing can be made more verbose.
mbox (mb) The given message list is to be sent to the secondary
mailbox MBOX when S-nail is quit; this is the default action
unless the variable hold is set. [v15 behaviour may differ]
This command can only be used in a primary system mailbox.
mimetype, unmimetype
[Only new quoting rules] Without arguments the content of the
MIME type cache will displayed; a more verbose listing will be
produced if either of debug or verbose are set. When given ar-
guments they will be joined, interpreted as shown in The
mime.types files (also see HTML mail and MIME attachments), and
the resulting entry will be added (prepended) to the cache. In
any event MIME type sources are loaded first as necessary -
mimetypes-load-control can be used to fine-tune which sources
are actually loaded.
The latter command deletes all specifications of the given MIME
type, thus `? unmimetype text/plain' will remove all registered
specifications for the MIME type `text/plain'. The special
name `*' will discard all existing MIME types, just as will
`reset', but which also reenables cache initialization via
mimetypes-load-control.
mimeview [v15 behaviour may differ] Only available in interactive mode,
this command allows execution of external MIME type handlers
which do not integrate into the normal type output (see HTML
mail and MIME attachments). ([v15 behaviour may differ] No
syntax to directly address parts, this restriction may vanish.)
The user will be asked for each non-text part of the given mes-
sage in turn whether the registered handler shall be used to
display the part.
mlist, unmlist
[Only new quoting rules] Manage the list of known Mailing
lists; subscriptions are controlled via mlsubscribe. The lat-
ter command deletes all given arguments, or all at once when
given the asterisk `*'. The former shows the list of all cur-
rently known lists if used without arguments, otherwise the
given arguments will become known. [Option] In the latter
case, arguments which contain any of the magic regular
expression characters will be interpreted as one, possibly
matching many addresses; these will be sequentially matched via
linked lists instead of being looked up in a dictionary.
mlsubscribe, unmlsubscribe
Building upon the command pair mlist, unmlist, but only manag-
ing the subscription attribute of mailing lists. (The former
will also create not yet existing mailing lists.)
Move Similar to move, but move the messages to a file named after
the local part of the sender of the first message instead of
taking a filename argument; outfolder is inspected to decide on
the actual storage location.
move Acts like copy but marks the messages for deletion if they were
transferred successfully.
More Like more, but also displays header fields which would not pass
the headerpick selection, and all MIME parts. Identical to
Page.
more Invokes the PAGER on the given messages, even in non-interac-
tive mode and as long as the standard output is a terminal.
Identical to page.
mtaaliases
[Option] When used without arguments or if show has been given
the content of the mta-aliases cache is shown, (re-)initializ-
ing it first (as necessary). If the argument is load then the
cache will only be (re-)initialized, and clear will remove its
contents.
netrc [Option] When used without arguments, or when the argument was
show the content of the ~/.netrc cache is shown, initializing
it as necessary. If the argument is load then the cache will
be (re)loaded, whereas clear removes it. Loading and parsing
can be made more verbose. lookup will query the cache for the
URL given as the second argument (`[USER@]HOST'). See
netrc-lookup, netrc-pipe and the section On URL syntax and
credential lookup; the section The .netrc file documents the
file format in detail.
newmail Checks for new mail in the current folder without committing
any changes before. If new mail is present, a message is
shown. If the header variable is set, the headers of each new
message are also shown. This command is not available for all
mailbox types.
next (n) (like `+' or "ENTER") Goes to the next message in sequence
and types it. With an argument list, types the next matching
message.
New Same as Unread.
new Same as unread.
noop If the current folder is accessed via a network connection, a
"NOOP" command is sent, otherwise no operation is performed.
Page Like page, but also displays header fields which would not pass
the headerpick selection, and all MIME parts. Identical to
More.
page Invokes the PAGER on the given messages, even in non-interac-
tive mode and as long as the standard output is a terminal.
Identical to more.
Pipe Like pipe but also pipes header fields which would not pass the
headerpick selection, and all parts of MIME
`multipart/alternative' messages.
pipe (pi) Takes an optional message list and shell command (that de-
faults to cmd), and pipes the messages through the command. If
the page variable is set, every message is followed by a form-
feed character.
preserve (pre) A synonym for hold.
Print (P) Alias for Type.
print (p) Research UNIX equivalent of type.
quit (q) Terminates the session, saving all undeleted, unsaved mes-
sages in the current secondary mailbox MBOX, preserving all
messages marked with hold or preserve or never referenced in
the system inbox, and removing all other messages from the
primary system mailbox. If new mail has arrived during the
session, the message "You have new mail" will be shown. If
given while editing a mailbox file with the command line option
-f, then the edit file is rewritten. A return to the shell is
effected, unless the rewrite of edit file fails, in which case
the user can escape with the exit command. The optional status
number argument will be passed through to exit(3). [v15 behav-
iour may differ] For now it can happen that the given status
will be overwritten, later this will only occur if a later er-
ror needs to be reported onto an otherwise success indicating
status.
read [Only new quoting rules] Read a line from standard input, or
the channel set active via readctl, and assign the data, which
will be split as indicated by ifs, to the given variables. The
variable names are checked by the same rules as documented for
vput, and the same error codes will be seen in !; the exit sta-
tus ? indicates the number of bytes read, it will be `-1' with
the error number ! set to ^ERR-BADF in case of I/O errors, or
^ERR-NONE upon End-Of-File. If there are more fields than
variables, assigns successive fields to the last given vari-
able. If there are less fields than variables, assigns the
empty string to the remains.
? read a b c
H e l l o
? echo "<$a> <$b> <$c>"
<H> <e> <l l o>
? wysh set ifs=:; read a b c;unset ifs
hey2.0,:"'you ",:world!:mars.:
? echo $?/$^ERRNAME / <$a><$b><$c>
0/NONE / <hey2.0,><"'you ",><world!:mars.:><><>
readsh [Only new quoting rules] Like read, but splits on shell token
boundaries (see Shell-style argument quoting) rather than at
ifs. [v15 behaviour may differ] Could become a commandalias,
maybe `read --tokenize --'.
readall [Only new quoting rules] Read anything from standard input, or
the channel set active via readctl, and assign the data to the
given variable. The variable name is checked by the same rules
as documented for vput, and the same error codes will be seen
in !; the exit status ? indicates the number of bytes read, it
will be `-1' with the error number ! set to ^ERR-BADF in case
of I/O errors, or ^ERR-NONE upon End-Of-File. [v15 behaviour
may differ] The input data length is restricted to 31-bits.
readctl [Only new quoting rules] Manages input channels for read,
readsh and readall, to be used to avoid complicated or imprac-
ticable code, like calling read from within a macro in non-in-
teractive mode. Without arguments, or when the first argument
is show, a listing of all known channels is printed. Channels
can otherwise be created, and existing channels can be set ac-
tive and removed by giving the string used for creation.
The channel name is expected to be a file descriptor number,
or, if parsing the numeric fails, an input file name that un-
dergoes Filename transformations. For example (this example
requires a modern shell):
$ printf 'echon "hey, "\nread a\nyou\necho $a' |\
s-nail -R#
hey, you
$ LC_ALL=C printf 'echon "hey, "\nread a\necho $a' |\
LC_ALL=C 6<<< 'you' s-nail -R#X'readctl create 6'
hey, you
remove [Only new quoting rules] Removes the named files or directo-
ries. If a name refers to a mailbox, say a Maildir mailbox,
then a mailbox type specific removal will be performed, delet-
ing the complete mailbox. In interactive mode the user is
asked for confirmation.
rename [Only new quoting rules] Takes the name of an existing folder
and the name for the new folder and renames the first to the
second one. Filename transformations including shell pathname
wildcard pattern expansions (glob(7)) are performed on both ar-
guments. Both folders must be of the same type.
Reply, Respond
(Compose mode)(R) Identical to reply except that it replies to
only the sender of each message of the given list, by using the
first message as the template to quote, for the `Subject:'
etc.; setting flipr will exchange this command with reply.
reply, respond
(Compose mode)(r) Take a message (list) and group-respond (to
each in turn) by addressing the sender and all recipients, sub-
ject to fullnames and alternates processing. followup-to,
followup-to-honour, reply-to-honour as well as recipients-in-cc
influence response behaviour. quote as well as
quote-as-attachment configure whether responded-to message
shall be quoted etc., content-description-quote-attachment may
be used. Setting flipr will exchange this command with Reply.
The command Lreply offers special support for replying to mail-
ing lists. For more documentation please refer to On sending
mail, and non-interactive mode.
This may generate the errors ^ERR-DESTADDRREQ if no receiver
has been specified, or was rejected by expandaddr policy,
^ERR-IO if an I/O error occurs, ^ERR-NOTSUP if a necessary
character set conversion fails, and ^ERR-INVAL for other er-
rors. It can also fail with errors of Specifying messages.
Any error stops processing of further messages.
Resend Like resend, but does not add any header lines. This is not a
way to hide the sender's identity, but useful for sending a
message again to the same recipients.
resend Takes a list of messages and a name, and sends each message to
the given addressee, which is subject to fullnames.
`Resent-From:' and related header fields are prepended to the
new copy of the message. Saving in record is only performed if
record-resent is set. [v15 behaviour may differ](Compose mode)
is not entered, the only supported hooks are on-resend-enter
and on-resend-cleanup.
This may generate the errors ^ERR-DESTADDRREQ if no receiver
has been specified, or was rejected by expandaddr policy,
^ERR-IO if an I/O error occurs, ^ERR-NOTSUP if a necessary
character set conversion fails, and ^ERR-INVAL for other er-
rors. It can also fail with errors of Specifying messages.
Any error stops processing of further messages.
retain (ret) Superseded by the multiplexer headerpick.
return Only available inside of a defined macro or an account, this
command returns control of execution to the outer scope. The
two optional parameters are positive decimal numbers and de-
fault to 0: the first specifies the 32-bit return value (stored
in ? [v15 behaviour may differ] and later extended to 64-bit),
the second the 32-bit error number (stored in !). As docu-
mented for ? a non-0 exit status may cause the program to exit.
Save (S) Similar to save, but saves the messages in a file named af-
ter the local part of the sender of the first message instead
of taking a filename argument; outfolder is inspected to decide
on the actual storage location.
save (s) Takes a message list and a filename and appends each mes-
sage in turn to the end of the file. Filename transformations
including shell pathname wildcard pattern expansions (glob(7))
is performed on the filename. If no filename is given, the
secondary mailbox MBOX is used. The filename in quotes, fol-
lowed by the generated character count is echoed on the user's
terminal. If editing a primary system mailbox the messages are
marked for deletion. To filter the saved header fields to the
desired subset use the `save' slot of the white- and blacklist-
ing command headerpick. Also see Copy.
savediscard
[Obsolete] Superseded by the multiplexer headerpick.
saveignore
[Obsolete] Superseded by the multiplexer headerpick.
saveretain
[Obsolete] Superseded by the multiplexer headerpick.
search Takes a message specification (list) and displays a header sum-
mary of all matching messages, as via headers. This command is
an alias of from. Also see Specifying messages.
seen Takes a message list and marks all messages as having been
read.
set, unset
(se, [Only new quoting rules] uns) The latter command will
delete all given global variables, or only block-scope local
ones if the local command modifier has been used. The former,
when used without arguments, will show all currently known
variables, being more verbose if either of debug or verbose is
set. Remarks: this list mode will not automatically link-in
(known) ENVIRONMENT variables, this only happens for explicit
addressing, examples are varshow, using a variable in an if
condition or a string passed to echo, explicit setting, as well
as some program-internal use cases (look-ups).
Otherwise the given variables (and arguments) are set or ad-
justed. Arguments are of the form `name=value' (no space be-
fore or after `='), or plain `name' if there is no value, i.e.,
a boolean variable. If a name begins with `no', as in `set
nosave', the effect is the same as invoking the unset command
with the remaining part of the variable (`unset save'). [v15
behaviour may differ] In conjunction with the wysh (or local)
command prefix(es) Shell-style argument quoting can be used to
quote arguments as necessary. [v15 behaviour may differ] Oth-
erwise quotation marks may be placed around any part of the as-
signment statement to quote blanks or tabs.
When operating in global scope any `name' that is known to map
to an environment variable will automatically cause updates in
the program environment (unsetting a variable in the environ-
ment requires corresponding system support) -- use the command
environ for further environmental control. If the command mod-
ifier local has been used to enforce local scoping then the
given user variables will be garbage collected when the local
scope is left; for INTERNAL VARIABLES, however, local behaves
the same as if localopts would have been set (temporarily),
which means that changes are inherited by deeper scopes. Also
see varshow and the sections INTERNAL VARIABLES and
ENVIRONMENT.
? wysh set indentprefix=' -> '
? wysh set atab=$'' aspace=' ' zero=0
shcodec Apply shell quoting rules to the given raw-data arguments.
Supports vput (see Command modifiers). The first argument
specifies the operation: [+]e[ncode] or d[ecode] cause shell
quoting to be applied to the remains of the line, and expanded
away thereof, respectively. If the former is prefixed with a
plus-sign, the quoted result will not be roundtrip enabled, and
thus can be decoded only in the very same environment that was
used to perform the encode; also see mle-quote-rndtrip. If the
coding operation fails the error number ! is set to
^ERR-CANCELED, and the unmodified input is used as the result;
the error number may change again due to output or result stor-
age errors.
shell [Only new quoting rules] (sh) Invokes an interactive version of
the shell, and returns its exit status.
shortcut, unshortcut
[Only new quoting rules] Manage the file- or pathname shortcuts
as documented for folder. The latter command deletes all
shortcuts given as arguments, or all at once when given the as-
terisk `*'. The former shows the list of all currently defined
shortcuts if used without arguments, the target of the given
with a single argument. Otherwise arguments are treated as
pairs of shortcuts and their desired expansion, creating new or
updating already existing ones.
shift [Only new quoting rules] Shift the positional parameter stack
(starting at 1) by the given number (which must be a positive
decimal), or 1 if no argument has been given. It is an error
if the value exceeds the number of positional parameters. If
the given number is 0, no action is performed, successfully.
The stack as such can be managed via vpospar. Note this com-
mand will fail in account and hook macros unless the positional
parameter stack has been explicitly created in the current con-
text via vpospar.
show Like type, but performs neither MIME decoding nor decryption,
so that the raw message text is shown.
size (si) Shows the size in characters of each message of the given
message list.
sleep [Only new quoting rules] Sleep for the specified number of sec-
onds (and optionally milliseconds), by default interruptible.
If a third argument is given the sleep will be uninterruptible,
otherwise the error number ! will be set to ^ERR-INTR if the
sleep has been interrupted. The command will fail and the er-
ror number will be ^ERR-OVERFLOW if the given duration(s) over-
flow the time datatype, and ^ERR-INVAL if the given durations
are no valid integers.
sort, unsort
The latter command disables sorted or threaded mode, returns to
normal message order and, if the header variable is set, dis-
plays a header summary. The former command shows the current
sorting criterion when used without an argument, but creates a
sorted representation of the current folder otherwise, and
changes the next command and the addressing modes such that
they refer to messages in the sorted order. Message numbers
are the same as in regular mode. If the header variable is
set, a header summary in the new order is also displayed. Au-
tomatic folder sorting can be enabled by setting the autosort
variable, as in `set autosort=thread'. Possible sorting crite-
rions are:
date Sort the messages by their `Date:' field, that is by
the time they were sent.
from Sort messages by the value of their `From:' field,
that is by the address of the sender. If the showname
variable is set, the sender's real name (if any) is
used.
size Sort the messages by their size.
spam [Option] Sort the message by their spam score, as has
been classified by spamrate.
status Sort the messages by their message status.
subject Sort the messages by their subject.
thread Create a threaded display.
to Sort messages by the value of their `To:' field, that
is by the address of the recipient. If the showname
variable is set, the recipient's real name (if any) is
used.
source [Only new quoting rules] (so) The source command reads commands
from the given file. Filename transformations will be applied.
If the given expanded argument ends with a vertical bar `|'
then the argument will instead be interpreted as a shell com-
mand and S-nail will read the output generated by it. Depen-
dent on the settings of posix and errexit, and also dependent
on whether the command modifier ignerr had been used, encoun-
tering errors will stop sourcing of the given input. [v15 be-
haviour may differ] Note that source cannot be used from within
macros that execute as folder-hooks or accounts, i.e., it can
only be called from macros that were called.
source_if
[Only new quoting rules] The difference to source (beside not
supporting pipe syntax aka shell command input) is that this
command will not generate an error nor warn if the given file
argument cannot be opened successfully.
spamclear
[Option] Takes a list of messages and clears their `is-spam'
flag.
spamforget
[Option] Takes a list of messages and causes the spam-interface
to forget it has ever used them to train its Bayesian filter.
Unless otherwise noted the `is-spam' flag of the message is in-
spected to chose whether a message shall be forgotten to be
"ham" or "spam".
spamham [Option] Takes a list of messages and informs the Bayesian fil-
ter of the spam-interface that they are "ham". This also
clears the `is-spam' flag of the messages in question.
spamrate [Option] Takes a list of messages and rates them using the con-
figured spam-interface, without modifying the messages, but
setting their `is-spam' flag as appropriate; because the spam
rating headers are lost the rate will be forgotten once the
mailbox is left. Refer to the manual section Handling spam for
the complete picture of spam handling in S-nail.
spamset [Option] Takes a list of messages and sets their `is-spam'
flag.
spamspam [Option] Takes a list of messages and informs the Bayesian fil-
ter of the spam-interface that they are "spam". This also sets
the `is-spam' flag of the messages in question.
thread [Obsolete] The same as `sort thread' (consider using a
`commandalias' as necessary).
tls [Only new quoting rules] TLS information and management command
multiplexer to aid in Encrypted network communication, mostly
available only if the term `,+sockets,' is included in
features. Commands support vput if so documented (see Command
modifiers). The result that is shown in case of errors is al-
ways the empty string, errors can be identified via the error
number !. For example, string length overflows are caught and
set ! to ^ERR-OVERFLOW. The TLS configuration is honoured, es-
pecially tls-verify.
? vput tls result fingerprint pop3s://ex.am.ple
? echo $?/$!/$^ERRNAME: $result
certchain Show the complete verified peer certificate chain.
Includes informational fields in conjunction with
verbose.
certificate Show only the peer certificate, without any sign-
ers. Includes informational fields in conjunction
with verbose.
fingerprint Show the tls-fingerprint-digested fingerprint of
the certificate of the given HOST (`server:port',
where the port defaults to the HTTPS port, 443).
tls-fingerprint is actively ignored for the runtime
of this command.
Top Like top but always uses the headerpick `type' slot for white-
and blacklisting header fields.
top (to) Takes a message list and types out the first toplines
lines of each message on the user's terminal. Unless a special
selection has been established for the `top' slot of the
headerpick command, the only header fields that are displayed
are `From:', `To:', `Cc:', and `Subject:'. Top will always use
the `type' headerpick selection instead. It is possible to ap-
ply compression to what is displayed by setting topsqueeze.
Messages are decrypted and converted to the terminal character
set if necessary.
touch (tou) Takes a message list and marks the messages for saving in
the secondary mailbox MBOX. S-nail deviates from the POSIX
standard with this command, as a following next command will
display the following message instead of the current one.
Type (T) Like type but also displays header fields which would not
pass the headerpick selection, and all visualizable parts of
MIME `multipart/alternative' messages.
type (t) Takes a message list and types out each message on the
user's terminal. The display of message headers is selectable
via headerpick. For MIME multipart messages, all parts with a
content type of `text', all parts which have a registered MIME
type handler (see HTML mail and MIME attachments) which pro-
duces plain text output, and all `message' parts are shown,
others are hidden except for their headers. Messages are de-
crypted and converted to the terminal character set if neces-
sary. The command mimeview can be used to display parts which
are not displayable as plain text.
unaccount
See account.
unalias (una) See alias.
unanswered
See answered.
unbind See bind.
uncollapse
See collapse.
uncolour See colour.
undefine See define.
undelete See delete.
undraft See draft.
unflag See flag.
unfwdignore
[Obsolete] Superseded by the multiplexer headerpick.
unfwdretain
[Obsolete] Superseded by the multiplexer headerpick.
unignore Superseded by the multiplexer headerpick.
unmimetype
See mimetype.
unmlist See mlist.
unmlsubscribe
See mlsubscribe.
Unread Same as unread.
unread Takes a message list and marks each message as not having been
read.
unretain Superseded by the multiplexer headerpick.
unsaveignore
[Obsolete] Superseded by the multiplexer headerpick.
unsaveretain
[Obsolete] Superseded by the multiplexer headerpick.
unset [Only new quoting rules] (uns) See set.
unshortcut
See shortcut.
unsort See short.
unthread [Obsolete] Same as unsort.
urlcodec Perform URL percent codec operations on the raw-data argument,
rather according to RFC 3986. The first argument specifies the
operation: e[ncode] or d[ecode] perform plain URL percent en-
and decoding, respectively. p[ath]enc[ode] and p[ath]dec[ode]
perform a slightly modified operation which should be better
for pathnames: it does not allow a tilde `~', and will neither
accept hyphen-minus `-' nor dot `'. as an initial character.
The remains of the line form the URL data which is to be con-
verted. This is a character set agnostic operation, and it may
thus decode bytes which are invalid in the current ttycharset.
Supports vput (see Command modifiers), and manages the error
number !. If the coding operation fails the error number ! is
set to ^ERR-CANCELED, and the unmodified input is used as the
result; the error number may change again due to output or re-
sult storage errors. [v15 behaviour may differ] This command
does not know about URLs beside what is documented. (vexpr of-
fers a makeprint subcommand, shall the URL be displayed.)
varshow [Only new quoting rules] This command produces the same output
as the listing mode of set, including verboseity adjustments,
but only for the given variables.
verify [Option] Takes a message list and verifies each message. If a
message is not a S/MIME signed message, verification will fail
for it. The verification process checks if the message was
signed using a valid certificate, if the message sender's email
address matches one of those contained within the certificate,
and if the message content has been altered.
version Shows the version and features of S-nail, optionally in a more
verbose form which also includes the build and running system
environment. This command supports vput (see Command
modifiers).
vexpr [Only new quoting rules] A multiplexer command which offers
signed 64-bit numeric calculations, as well as other, mostly
string-based operations. C-style byte string operations are
available via csop. The first argument defines the number,
type, and meaning of the remaining arguments. An empty number
argument is treated as 0. Supports vput (see Command
modifiers). The result shown in case of errors is `-1' for us-
age errors and numeric operations, the empty string otherwise;
"soft" errors, like when a search operation failed, will also
set the ! error number to ^ERR-NODATA. Except when otherwise
noted numeric arguments are parsed as signed 64-bit numbers,
and errors will be reported in the error number ! as the nu-
meric error ^ERR-RANGE.
Numeric operations work on one or two signed 64-bit integers.
Numbers prefixed with `0x' or `0X' are interpreted as hexadeci-
mal (base 16) numbers, whereas `0' indicates octal (base 8),
and `0b' as well as `0B' denote binary (base 2) numbers. It is
possible to use any base in between 2 and 36, inclusive, with
the `BASE#number' notation, where the base is given as an un-
signed decimal number, so `16#AFFE' is a different way of spec-
ifying a hexadecimal number. Unsigned interpretation of a num-
ber can be enforced by prefixing an `u' (case-insensitively),
as in `u-110'; this is not necessary for power-of-two bases (2,
4, 8, 16 and 32), which will be interpreted as unsigned by de-
fault, but it still makes a difference regarding overflow de-
tection and overflow constant. It is possible to enforce
signed interpretation by (instead) prefixing a `s' (case-insen-
sitively). The number sign notation uses a permissive parse
mode and as such supports complicated conditions out of the
box:
? wysh set ifs=:;read i;unset ifs;echo $i;vexpr pb 2 10#$i
-009
< -009>
0b1001
One integer is expected by assignment (equals sign `='), which
does nothing but parsing the argument, thus detecting validity
and possible overflow conditions, unary not (tilde `~'), which
creates the bitwise complement, and unary plus and minus. Two
integers are used by addition (plus sign `+'), subtraction (hy-
phen-minus `-'), multiplication (asterisk `*'), division
(solidus `/') and modulo (percent sign `%'), as well as for the
bitwise operators logical or (vertical bar `|', to be quoted) ,
bitwise and (ampersand `&', to be quoted) , bitwise xor (cir-
cumflex `^'), the bitwise signed left- and right shifts (`<<',
`>>'), as well as for the unsigned right shift `>>>'.
Another numeric operation is pbase, which takes a number base
in between 2 and 36, inclusive, and will act on the second num-
ber given just the same as what equals sign `=' does, but the
number result will be formatted in the base given, as a signed
64-bit number unless unsigned interpretation of the input num-
ber had been forced (with an u prefix).
Numeric operations support a saturated mode via the question
mark `?' modifier suffix; the keyword `saturated' is optional,
`+?', `+?satu', and `+?saturated' are therefore identical. In
saturated mode overflow errors and division and modulo by zero
are no longer reported via the exit status, but the result will
linger at the minimum or maximum possible value, instead of
overflowing (or trapping). This is true also for the argument
parse step. For the bitwise shifts, the saturated maximum is
63. Any caught overflow will be reported via the error number
! as ^ERR-OVERFLOW.
? vput vexpr res -? +1 -9223372036854775808
? echo $?/$!/$^ERRNAME:$res
0/75/OVERFLOW:-9223372036854775808
Character set agnostic string functions have no notion of lo-
cale settings and character sets.
date-utc Outputs the current date and time in UTC (Coordinated
Universal Time) with values named such that `vput
vexpr x date-utc; eval wysh set $x' creates accessi-
ble variables.
date-stamp-utc Outputs a RFC 3339 internet date/time format of
UTC.
epoch The seconds and nanoseconds since the Unix epoch
(1970-01-01T00:00:00) named `epoch_sec' and
`epoch_nsec' such that `vput vexpr x epoch; eval wysh
set $x' creates accessible variables.
file-expand Performs the usual Filename transformations on its
argument.
file-stat, file-lstat Perform the usual Filename
transformations on the argument, then call stat(2)
and lstat(2), respectively, and output values such
that `vput vexpr x file-stat FILE; eval wysh set $x'
creates accessible variables. The variable `st_type'
uses solidus `/' to denote directories, commercial at
`@' for links, number sign `#' for block devices,
percent sign `%' for for character devices, vertical
bar `|' for FIFOs, equal sign `=' for sockets, and
the period `.' for the rest.
random Generates a random string of the given length, or of
PATH_MAX bytes (a constant from /usr/include) if the
value 0 is given; the random string will be base64url
encoded according to RFC 4648, and thus be usable as
a (portable) filename.
String operations work, sufficient support provided, according
to the active user's locale encoding and character set (see
Character sets). Where the question mark `?' modifier suffix
is supported, a case-insensitive operation mode is available;
the keyword `case' is optional, `regex?' and `regex?case' are
therefore identical.
makeprint (One-way) Converts the argument to something safely
printable on the terminal.
regex [Option] A string operation that will try to match
the first argument with the regular expression given
as the second argument. `?' modifier suffix is sup-
ported. If the optional third argument has been
given then instead of showing the match offset a re-
placement operation is performed: the third argument
is treated as if specified within dollar-single-quote
(see Shell-style argument quoting), and any occur-
rence of a positional parameter, for example 0, 1
etc. is replaced with the according match group of
the regular expression:
? vput vexpr res regex bananarama \
(.*)NanA(.*) '\${1}au\$2'
? echo $?/$!/$^ERRNAME:$res:
1/61/NODATA::
? vput vexpr res regex?case bananarama \
(.*)NanA(.*) '\${1}uauf\$2'
? echo $?/$!/$^ERRNAME:$res:
0/0/NONE:bauauframa:
vpospar [Only new quoting rules] Manage the positional parameter stack
(see 1, #, *, @ as well as shift). If the first argument is
`clear', then the positional parameter stack of the current
context, or the global one, if there is none, is cleared. If
it is `set', then the remaining arguments will be used to
(re)create the stack, if the parameter stack size limit is ex-
cessed an ^ERR-OVERFLOW error will occur.
If the first argument is `quote', a round-trip capable repre-
sentation of the stack contents is created, with each quoted
parameter separated from each other with the first character of
ifs, and followed by the first character of if-ws, if that is
not empty and not identical to the first. If that results in
no separation at all a space character is used. This mode sup-
ports vput (see Command modifiers). I.e., the subcommands
`set' and `quote' can be used (in conjunction with eval) to
(re)create an argument stack from and to a single variable
losslessly.
? vpospar set hey, "'you ", world!
? echo $#: <${1}><${2}><${3}>
? vput vpospar x quote
? vpospar clear
? echo $#: <${1}><${2}><${3}>
? eval vpospar set ${x}
? echo $#: <${1}><${2}><${3}>
visual (v) Takes a message list and invokes the VISUAL display editor
on each message. Modified contents are discarded unless the
writebackedited variable is set, and are not used unless the
mailbox can be written to and the editor returns a successful
exit status. edit can be used instead for a less display ori-
ented editor.
write (w) For conventional messages the body without all headers is
written. The original message is never marked for deletion in
the originating mail folder. The output is decrypted and con-
verted to its native format as necessary. If the output file
exists, the text is appended. If a message is in MIME multi-
part format its first part is written to the specified file as
for conventional messages, handling of the remains depends on
the execution mode. No special handling of compressed files is
performed.
In interactive mode the user is consecutively asked for the
filenames of the processed parts. For convenience saving of
each part may be skipped by giving an empty value, the same re-
sult as writing it to /dev/null. Shell piping the part content
by specifying a leading vertical bar `|' character for the
filename is supported. Other user input undergoes the usual
Filename transformations, including shell pathname wildcard
pattern expansions (glob(7)) and shell variable expansion for
the message as such, not the individual parts, and contents of
the destination file are overwritten if the file previously ex-
isted. Character set conversion to ttycharset is performed
when saving text data.
[v15 behaviour may differ] In non-interactive mode any part
which does not specify a filename is ignored, and suspicious
parts of filenames of the remaining parts are URL percent en-
coded (as via urlcodec) to prevent injection of malicious char-
acter sequences, resulting in a filename that will be written
into the current directory. Existing files will not be over-
written, instead the part number or a dot are appended after a
number sign `#' to the name until file creation succeeds (or
fails due to other reasons).
xcall [Only new quoting rules] The sole difference to call is that
the new macro is executed in place of the current one, which
will not regain control: all resources of the current macro
will be released first. This implies that any setting covered
by localopts will be forgotten and covered variables will be-
come cleaned up. If this command is not used from within a
called macro it will silently be (a more expensive variant of)
call.
xit (x) A synonym for exit.
z [Only new quoting rules] S-nail presents message headers in
screenfuls as described under the headers command. Without ar-
guments this command scrolls to the next window of messages,
likewise if the argument is `+'. An argument of `-' scrolls to
the last, `^' scrolls to the first, and `$' to the last screen
of messages. A number argument prefixed by `+' or `-' indi-
cates that the window is calculated in relation to the current
position, and a number without a prefix specifies an absolute
position.
Z [Only new quoting rules] Similar to z, but scrolls to the next
or previous window that contains at least one `new' or flagged
message.
COMMAND ESCAPES
Command escapes are available in Compose mode during interactive usage,
when explicitly requested via -~, and in batch mode (-#). They perform
special functions, like editing headers of the message being composed,
calling normal COMMANDS, yielding a shell, etc. Command escapes are only
recognized at the beginning of lines, and consist of an escape followed
by a command character. The default escape character is the tilde `~'.
Unless otherwise documented command escapes ensure proper updates of the
error number ! and the exit status ?. The variable errexit controls
whether a failed operation errors out message compose mode and causes
program exit. Escapes may be prefixed by none to multiple single charac-
ter command modifiers, interspersed whitespace is ignored:
o An effect equivalent to the command modifier ignerr can be achieved
with hyphen-minus `-', overriding errexit.
o The modifier dollar `$' evaluates the remains of the line; also see
Shell-style argument quoting. [v15 behaviour may differ] For now the
entire input line is evaluated as a whole; to avoid that control op-
erators like semicolon ; are interpreted unintentionally, they must
be quoted.
Addition of the command line to the [Option]al history can be prevented
by placing whitespace directly after escape. The [Option]al key bindings
support a compose mode specific context. The following command escapes
are supported:
~~ string
Insert the string of text in the message prefaced by a single
`~'. (If the escape character has been changed, that character
must be doubled instead.)
~! command
Execute the indicated shell command which follows, replacing
unescaped exclamation marks with the previously executed com-
mand if the internal variable bang is set, then return to the
message.
~. End compose mode and send the message. The hooks
on-compose-splice-shell and on-compose-splice, in order, will
be called when set, after which, in interactive mode askatend
(leading to askcc, askbcc) and askattach will be checked as
well as asksend, after which a set on-compose-leave hook will
be called, autocc and autobcc will be joined in if set, finally
a given message-inject-tail will be incorporated, after which
the compose mode is left.
~: S-nail-command or ~_ S-nail-command
Can be used to execute COMMANDS (which are allowed in compose
mode).
~< filename
Identical to ~r.
~<! command
command is executed using the shell. Its standard output is
inserted into the message.
~? [Option] Write a summary of command escapes.
~@ [filename...]
Append or edit the list of attachments. Does not manage the
error number ! and the exit status ? (please use ~^ if error
handling is necessary). The append mode expects a list of
filename arguments as shell tokens (see Shell-style argument
quoting; token-separating commas are ignored, too), to be in-
terpreted as documented for the command line option -a, with
the message number exception as below.
Without filename arguments the attachment list is edited, entry
by entry; if a filename is left empty, that attachment is
deleted from the list; once the end of the list is reached ei-
ther new attachments may be entered or the session can be quit
by committing an empty "new" attachment. In non-interactive
mode or in batch mode (-#) the list of attachments is effec-
tively not edited but instead recreated; again, an empty input
ends list creation.
For all modes, if a given filename solely consists of the num-
ber sign `#' followed by either a valid message number of the
currently active mailbox, or by a period `.', referring to the
current message of the active mailbox, the so-called "dot",
then the given message is attached as a `message/rfc822' MIME
message part. The number sign must be quoted to avoid misin-
terpretation as a shell comment character.
~| command
Pipe the message text through the specified filter command. If
the command gives no output or terminates abnormally, retain
the original text of the message. The command fmt(1) is often
used as a rejustifying filter.
If the first character of the command is a vertical bar, then
the entire message including header fields is subject to the
filter command, so `~|| echo Fcc: /tmp/test; cat' will prepend
a file-carbon-copy message header. Also see ~e, ~v.
~^ cmd [subcmd [arg3 [arg4]]]
Low-level compose mode command which shares semantics with
digmsg, and therefore evaluates its command line as documented
in Shell-style argument quoting. Does not manage the error
number ! and the exit status ?: errors are handled via the pro-
tocol, and hard errors like I/O failures cannot be handled.
The protocol consists of command lines followed by (a) response
line(s). The first field of the response line represents a
status code which specifies whether a command was successful or
not, whether result data is to be expected, and if, the format
of the result data. Response data will be shell quoted as nec-
essary for consumption by readsh, or eval and vpospar, to name
a few. Error status code lines may optionally contain addi-
tional context:
`210' Status ok; the remains of the line are the result.
`211' Status ok; the rest of the line is optionally used
for more status. What follows are lines of result
addresses, terminated by an empty line. All the in-
put, including the empty line, must be consumed be-
fore further commands can be issued. Address lines
consist of two token, first the plain network ad-
dress, e.g., `bob@exam.ple', followed by the (quoted)
full address as known: `'(Lovely) Bob
<bob@exam.ple>''. Non-network addresses use the
first field to indicate the type (hyphen-minus `-'
for files, vertical bar `|' for pipes, and number
sign `#' for names which will undergo alias process-
ing) instead, the actual value will be in the second
field.
`212' Status ok; the rest of the line is optionally used
for more status. What follows are lines of furtherly
unspecified (quoted) string content, terminated by an
empty line. All the input, including the empty line,
must be consumed before further commands can be is-
sued.
`500' Syntax error; invalid command.
`501' Syntax error in parameters or arguments.
`505' Error: an argument fails verification. For example
an invalid address has been specified (also see
expandaddr), or an attempt was made to modify any-
thing in S-nail's own namespace, or a modifying sub-
command has been used on a read-only message.
`506' Error: an otherwise valid argument is rendered in-
valid due to context. For example, a second address
is added to a header which may consist of a single
address only.
If a command indicates failure then the message will have re-
mained unmodified. Most commands can fail with `500' if re-
quired arguments are missing, or excessive arguments have been
given (false command usage). ([v15 behaviour may differ] The
latter does not yet occur regularly, because as stated in
Shell-style argument quoting our argument parser is not yet
smart enough to work on subcommand base; for example one might
get excess argument error for a three argument subcommand that
receives four arguments, but not for a four argument subcommand
which receives six arguments: here excess will be joined.) The
following (case-insensitive) commands are supported:
attachment This command allows listing, removal and addition of
message attachments. The second argument specifies
the subcommand to apply, one of:
attribute This uses the same search mechanism as de-
scribed for remove and prints any known at-
tributes of the first found attachment via
`212' upon success or `501' if no such at-
tachment can be found. The attributes are
written as lines with a keyword and a value
token.
attribute-at This uses the same search mechanism as
described for remove-at and is otherwise
identical to attribute.
attribute-set This uses the same search mechanism as
described for remove, and will set the at-
tribute given as the fourth to the value
given as the fifth token argument. If the
value is an empty token, then the given at-
tribute is removed, or reset to a default
value if existence of the attribute is cru-
cial.
It returns via `210' upon success, with the
index of the found attachment following,
`505' for message attachments or if the
given keyword is invalid, and `501' if no
such attachment can be found. The following
keywords may be used (case-insensitively):
`filename' Sets the filename of the MIME
part, i.e., the name that is
used for display and when (sug-
gesting a name for) saving (pur-
poses).
`content-description' Associate some de-
scriptive information to the at-
tachment's content, used in
favour of the plain filename by
some MUAs.
`content-id' May be used for uniquely iden-
tifying MIME entities in several
contexts; this expects a special
reference address format as de-
fined in RFC 2045 and generates
a `505' upon address content
verification failure.
`content-type' Defines the media type/sub-
type of the part, which is man-
aged automatically, but can be
overwritten.
`content-disposition' Automatically set to
the string `attachment'.
attribute-set-at This uses the same search mechanism
as described for remove-at and is otherwise
identical to attribute-set.
insert Adds the attachment given as the third argu-
ment, specified exactly as documented for
the command line option -a, and supporting
the message number extension as documented
for ~@. This reports `210' upon success,
with the index of the new attachment follow-
ing, `505' if the given file cannot be
opened, `506' if an on-the-fly performed
character set conversion fails, otherwise
`501' is reported; this is also reported if
character set conversion is requested but
not available.
list List all attachments via `212', or report
`501' if no attachments exist. This command
is the default command of attachment if no
second argument has been given.
remove This will remove the attachment given as the
third argument, and report `210' upon suc-
cess or `501' if no such attachment can be
found. If there exists any path component
in the given argument, then an exact match
of the path which has been used to create
the attachment is used directly, but if only
the basename of that path matches then all
attachments are traversed to find an exact
match first, and the removal occurs after-
wards; if multiple basenames match, a `506'
error occurs. Message attachments are
treated as absolute pathnames.
If no path component exists in the given ar-
gument, then all attachments will be
searched for `filename=' parameter matches
as well as for matches of the basename of
the path which has been used when the at-
tachment has been created; multiple matches
result in a `506'.
remove-at This will interpret the third argument as a
number and remove the attachment at that
list position (counting from one!), report-
ing `210' upon success or `505' if the argu-
ment is not a number or `501' if no such at-
tachment exists.
header This command allows listing, inspection, and editing
of message headers. Header name case is not normal-
ized, so that case-insensitive comparison should be
used when matching names. The second argument speci-
fies the subcommand to apply, one of:
insert Create a new or an additional instance of
the header given in the third argument, with
the header body content as given in the
fourth token. It may return `501' if the
third argument specifies a free-form header
field name that is invalid, or if body con-
tent extraction fails to succeed, `505' if
any extracted address does not pass syntax
and/or security checks or on S-nail name-
space violations, and `506' to indicate pre-
vention of excessing a single-instance
header -- note that `Subject:' can be ap-
pended to (a space separator will be added
automatically first). `To:', `Cc:' and
`Bcc:' support the `?single' modifier to en-
force treatment as a single addressee, for
example `header insert To?single: 'exa,
<m@ple>''; the word `single' is optional.
`210' is returned upon success, followed by
the name of the header and the list position
of the newly inserted instance. The list
position is always 1 for single-instance
header fields. All free-form header fields
are managed in a single list; also see
customhdr.
list Without a third argument a list of all yet
existing headers is given via `210'; this
command is the default command of header if
no second argument has been given. A third
argument restricts output to the given
header only, which may fail with `501' if no
such field is defined.
remove This will remove all instances of the header
given as the third argument, reporting `210'
upon success, `501' if no such header can be
found, and `505' on S-nail namespace viola-
tions.
remove-at This will remove from the header given as
the third argument the instance at the list
position (counting from one!) given with the
fourth argument, reporting `210' upon suc-
cess or `505' if the list position argument
is not a number or on S-nail namespace vio-
lations, and `501' if no such header in-
stance exists.
show Shows the content of the header given as the
third argument. Dependent on the header
type this may respond with `211' or `212';
any failure results in `501'.
In compose-mode read-only access to optional pseudo
headers in the S-nail private namespace is available:
`Mailx-Command:'
The name of the command that generates the
message, one of `forward', `Lreply', `mail',
`Reply', `reply', `resend'. This pseudo
header always exists (in compose-mode).
`Mailx-Raw-To:'
`Mailx-Raw-Cc:'
`Mailx-Raw-Bcc:'
Represent the frozen initial state of these
headers before any transformation (alias,
alternates, recipients-in-cc etc.) took
place.
`Mailx-Orig-Sender:'
`Mailx-Orig-From:'
`Mailx-Orig-To:'
`Mailx-Orig-Cc:'
`Mailx-Orig-Bcc:'
The values of said headers of the original
message which has been addressed by any of
reply, forward, resend. The sender field is
special as it is filled in with the sole
sender according to RFC 5322 rules, it may
thus be equal to the from field.
help, ? Show an abstract of the above commands via `211'.
version This command will print the protocol version via
`210'.
~A The same as `~i Sign'.
~a The same as `~i sign'.
~b name ...
Add the given names to the list of blind carbon copy recipi-
ents.
~c name ...
Add the given names to the list of carbon copy recipients.
~d Read the file specified by the DEAD variable into the message.
~e Invoke the text EDITOR on the message collected so far, then
return to compose mode. ~v can be used for a more display ori-
ented editor, and ~|| offers a pipe-based editing approach.
~F messages
Read the named messages into the message being sent, including
all message headers and MIME parts, and honouring
forward-add-cc as well as forward-inject-head and
forward-inject-tail. If no messages are specified, read in the
current message, the "dot".
~f messages
Read the named messages into the message being sent. If no
messages are specified, read in the current message, the "dot".
Strips down the list of header fields according to the
`forward' (with posix: `type') white- and blacklist selection
of headerpick, and honours forward-add-cc as well as
forward-inject-head and forward-inject-tail. For MIME multi-
part messages, only the first displayable part is included.
~H In interactive mode, edit the message header fields `From:',
`Reply-To:' and `Sender:' by typing each one in turn and allow-
ing the user to edit the field. The default values for these
fields originate from the from, reply-to and sender variables.
In non-interactive mode this sets ^ERR-NOTTY.
~h In interactive mode, edit the message header fields `To:',
`Cc:', `Bcc:' and `Subject:' by typing each one in turn and al-
lowing the user to edit the field. In non-interactive mode
this sets ^ERR-NOTTY.
~I variable
Insert the value of the specified variable into the message.
The message remains unaltered if the variable is unset or
empty. Any embedded character sequences `\t' horizontal tabu-
lator and `\n' line feed are expanded in posix mode; otherwise
the expansion should occur at set time ([v15 behaviour may dif-
fer] by using the command modifier wysh).
~i variable
Like ~I, but appends a newline character.
~M messages
Read the named messages into the message being sent, indented
by indentprefix. If no messages are specified, read the cur-
rent message, the "dot". Honours forward-add-cc as well as
forward-inject-head and forward-inject-tail.
~m messages
Read the named messages into the message being sent, indented
by indentprefix. If no messages are specified, read the cur-
rent message, the "dot". Strips down the list of header fields
according to the `type' white- and blacklist selection of
headerpick. Honours forward-add-cc as well as
forward-inject-head and forward-inject-tail. For MIME multi-
part messages, only the first displayable part is included.
~p Display the message collected so far, prefaced by the message
header fields and followed by the attachment list, if any.
~Q Read in the given / current message(s) using the algorithm of
quote (except that is implicitly assumed, even if not set),
honouring quote-add-cc.
~q Abort the message being sent, copying it to the file specified
by the DEAD variable if save is set.
~R filename
Identical to ~r, but indent each line that has been read by
indentprefix.
~r filename [HERE-delimiter]
Read the named file, object to Filename transformations exclud-
ing shell globs and variable expansions, into the message; if
filename is the hyphen-minus `-' then standard input is used
(for pasting, for example). Only in this latter mode
HERE-delimiter may be given: if it is data will be read in un-
til the given HERE-delimiter is seen on a line by itself, and
encountering EOF is an error; the HERE-delimiter is a required
argument in non-interactive mode; if it is single-quote quoted
then the pasted content will not be expanded, [v15 behaviour
may differ] otherwise a future version of S-nail may perform
shell-style expansion on the content.
~s string
Cause the named string to become the current subject field.
Newline (NL) and carriage-return (CR) bytes are invalid and
will be normalized to space (SP) characters.
~t name ...
Add the given name(s) to the direct recipient list.
~U messages
Read in the given / current message(s) excluding all headers,
indented by indentprefix. Honours forward-add-cc as well as
forward-inject-head and forward-inject-tail.
~u messages
Read in the given / current message(s), excluding all headers.
Honours forward-add-cc as well as forward-inject-head and
forward-inject-tail.
~v Invoke the VISUAL editor on the message collected so far, then
return to compose mode. ~e can be used for a less display ori-
ented editor, and ~|| offers a pipe-based editing approach.
~w filename
Write the message onto the named file, which is object to the
usual Filename transformations. If the file exists, the mes-
sage is appended to it.
~x Same as ~q, except that the message is not saved at all.
INTERNAL VARIABLES
Internal S-nail variables are controlled via the set and unset commands;
prefixing a variable name with the string `no' and calling set has the
same effect as using unset: `unset crt' and `set nocrt' do the same
thing. varshow will give more insight on the given variable(s), and set,
when called without arguments, will show a listing of all variables.
Both commands support a more verbose listing mode. Some well-known vari-
ables will also become inherited from the program ENVIRONMENT implicitly,
others can be imported explicitly with the command environ and henceforth
share said properties.
Two different kinds of internal variables exist, and both of which can
also form chains. There are boolean variables, which can only be in one
of the two states "set" and "unset", and value variables with a(n op-
tional) string value. For the latter proper quoting is necessary upon
assignment time, the introduction of the section COMMANDS documents the
supported quoting rules.
? wysh set one=val\ 1 two="val 2" \
three='val "3"' four=$'val \'4\''; \
varshow one two three four; \
unset one two three four
Dependent upon the actual option string values may become interpreted as
colour names, command specifications, normal text, etc. They may be
treated as numbers, in which case decimal values are expected if so docu-
mented, but otherwise any numeric format and base that is valid and un-
derstood by the vexpr command may be used, too.
There also exists a special kind of string value, the "boolean string",
which must either be a decimal integer (in which case `0' is false and
`1' and any other value is true) or any of the (case-insensitive) strings
`off', `no', `n' and `false' for a false boolean and `on', `yes', `y' and
`true' for a true boolean; a special kind of boolean string is the
"quadoption": it can optionally be prefixed with the (case-insensitive)
term `ask-', as in `ask-yes'; in interactive mode the user will be
prompted, otherwise the actual boolean is used.
Variable chains extend a plain `variable' with `variable-HOST' and
`variable-USER@HOST' variants. Here `HOST' will be converted to all low-
ercase when looked up (but not when the variable is set or unset!), [Op-
tion]ally IDNA converted, and indeed means `server:port' if a `port' had
been specified in the contextual Uniform Resource Locator URL, see On URL
syntax and credential lookup. Even though this mechanism is based on
URLs no URL percent encoding may be applied to neither of `USER' nor
`HOST', variable chains need to be specified using raw data; the men-
tioned section contains examples. Variables which support chains are ex-
plicitly documented as such, and S-nail treats the base name of any such
variable special, meaning that users should not create custom names like
`variable-xyz' in order to avoid false classifications and treatment of
such variables.
Initial settings
The standard POSIX 2008/Cor 2-2016 mandates the following initial vari-
able settings: noallnet, noappend, asksub, noaskbcc, noautoprint, nobang,
nocmd, nocrt, nodebug, nodot, escape set to `~', noflipr, nofolder,
header, nohold, noignore, noignoreeof, nokeep, nokeepsave, nometoo,
nooutfolder, nopage, prompt set to `? ', noquiet, norecord, save,
nosendwait, noshowto, noSign, nosign, toplines set to `5'.
However, S-nail has built-in some initial (and some default) settings
which (may) diverge, others may become adjusted by one of the Resource
files. Displaying the former is accomplished via set: `$ s-nail -:/ -v
-Xset -Xx'. In general this implementation sets (and has extended the
meaning of) sendwait, and does not support the noonehop variable - use
command line options or mta-arguments to pass options through to a mta.
The default global resource file sets, among others, the variables hold,
keep and keepsave, establishes a default headerpick selection etc., and
should thus be taken into account.
Variables
? (Read-only) The exit status of the last command, or the return
value of the macro called last. This status has a meaning in
the state machine: in conjunction with errexit any non-0 exit
status will cause a program exit, and in posix mode any error
while loading (any of the) resource files will have the same
effect. ignerr, one of the Command modifiers, can be used to
instruct the state machine to ignore errors.
! (Read-only) The current error number (errno(3)), which is set
after an error occurred; it is also available via ^ERR, and the
error name and documentation string can be queried via ^ERRNAME
and ^ERRDOC. [v15 behaviour may differ] This machinery is new
and the error number is only really usable if a command explic-
itly states that it manages the variable !, for others errno
will be used in case of errors, or ^ERR-INVAL if that is 0: it
thus may or may not reflect the real error. The error number
may be set with the command return.
^ (Read-only) This is a multiplexer variable which performs dy-
namic expansion of the requested state or condition, of which
there are:
^ERR, ^ERRDOC, ^ERRNAME
The number, documentation, and name of the current
errno(3), respectively, which is usually set after an
error occurred. The documentation is an [Option],
the name is used if not available. [v15 behaviour
may differ] This machinery is new and is usually re-
liable only if a command explicitly states that it
manages the variable !, which is effectively identi-
cal to ^ERR. Each of those variables can be suffixed
with a hyphen minus followed by a name or number, in
which case the expansion refers to the given error.
Note this is a direct mapping of (a subset of) the
system error values:
define work {
eval echo \$1: \$^ERR-$1:\
\$^ERRNAME-$1: \$^ERRDOC-$1
vput vexpr i + "$1" 1
if [ $i -lt 16 ]
\xcall work $i
end
}
call work 0
^ERRQUEUE-COUNT, ^ERRQUEUE-EXISTS
The number of messages present in the [Option]al log
queue of errors, and a boolean which indicates
whether the queue is not empty, respectively; both
are always 0 unless features includes `,+errors,'.
* (Read-only) Expands all positional parameters (see 1), sepa-
rated by the first character of the value of ifs. [v15 behav-
iour may differ] The special semantics of the equally named
special parameter of the sh(1) are not yet supported.
@ (Read-only) Expands all positional parameters (see 1), sepa-
rated by a space character. If placed in double quotation
marks, each positional parameter is properly quoted to expand
to a single parameter again.
# (Read-only) Expands to the number of positional parameters,
i.e., the size of the positional parameter stack in decimal.
0 (Read-only) Inside the scope of a defined and called macro this
expands to the name of the calling macro, or to the empty
string if the macro is running from top-level. For the [Op-
tion]al regular expression search and replace operator of vexpr
this expands to the entire matching expression. It represents
the program name in global context.
1 (Read-only) Access of the positional parameter stack. All fur-
ther parameters can be accessed with this syntax, too, `2', `3'
etc.; positional parameters can be shifted off the stack by
calling shift. The parameter stack contains, for example, the
arguments of a called defined macro, the matching groups of the
[Option]al regular expression search and replace expression of
vexpr, and can be explicitly created or overwritten with the
command vpospar.
account (Read-only) Is set to the active account.
add-file-recipients
(Boolean) When file or pipe recipients have been specified,
mention them in the corresponding address fields of the message
instead of silently stripping them from their recipient list.
By default such addressees are not mentioned.
allnet (Boolean) Causes only the local part to be evaluated when com-
paring addresses.
append (Boolean) Causes messages saved in the secondary mailbox MBOX
to be appended to the end rather than prepended. This should
always be set.
askatend (Boolean) Causes the prompts for `Cc:' and `Bcc:' lists to ap-
pear after the message has been edited.
askattach
(Boolean) If set, S-nail asks an interactive user for files to
attach at the end of each message; An empty line finalizes the
list.
askcc (Boolean) Causes the interactive user to be prompted for carbon
copy recipients (at the end of each message if askatend or
bsdcompat are set).
askbcc (Boolean) Causes the interactive user to be prompted for blind
carbon copy recipients (at the end of each message if askatend
or bsdcompat are set).
asksend (Boolean) Causes the interactive user to be prompted for con-
firmation to send the message or reenter compose mode after
having been shown a preliminary envelope summary.
asksign (Boolean)[Option] Causes the interactive user to be prompted if
the message is to be signed at the end of each message. The
smime-sign variable is ignored when this variable is set.
asksub (Boolean) Causes S-nail to prompt the interactive user for the
subject upon entering compose mode unless a subject already ex-
ists.
attrlist A sequence of characters to display in the `attribute' column
of the headline as shown in the display of headers; each for
one type of messages (see Message states), with the default be-
ing `NUROSPMFAT+-$~' or `NU *HMFAT+-$~' if the bsdflags vari-
able is set, in the following order:
`N' new.
`U' unread but old.
`R' new but read.
`O' read and old.
`S' saved.
`P' preserved.
`M' mboxed.
`F' flagged.
`A' answered.
`T' draft.
`+' [v15 behaviour may differ] start of a (collapsed)
thread in threaded mode (see autosort, thread);
`-' [v15 behaviour may differ] an uncollapsed thread in
threaded mode; only used in conjunction with -L.
`$' classified as spam.
`~' classified as possible spam.
autobcc Specifies a list of recipients to which a blind carbon copy of
each outgoing message will be sent automatically.
autocc Specifies a list of recipients to which a carbon copy of each
outgoing message will be sent automatically.
autocollapse
(Boolean) Causes threads to be collapsed automatically when .Ql
thread Ns ed sort mode is entered (see the collapse command).
autoprint
(Boolean) Enable automatic typeing of a(n existing)
"successive" message after delete and undelete commands: the
message that becomes the new "dot" is shown automatically, as
via dp or dt.
autosort Causes sorted mode (see the sort command) to be entered auto-
matically with the value of this variable as sorting method
when a folder is opened, for example `set autosort=thread'.
bang (Boolean) Enables the substitution of all not (reverse-solidus)
escaped exclamation mark `!' characters by the contents of the
last executed command for the ! shell escape command and ~!,
one of the compose mode COMMAND ESCAPES. If this variable is
not set no reverse solidus stripping is performed.
bind-timeout
[Obsolete] Predecessor of bind-inter-byte-timeout. [v15 behav-
iour may differ] Setting this automatically sets the successor.
bind-inter-byte-timeout
[Option] Terminals may generate multi-byte sequences for spe-
cial function keys, for example, but these sequences may not
become read as a unit. And multi-byte sequences can be defined
freely via bind. This variable specifies the timeout in mil-
liseconds that the MLE (see On terminal control and line
editor) waits for more bytes to arrive unless it considers a
sequence "complete". The default is 200, the maximum is about
10 seconds. In the following example the comments state which
sequences are affected by this timeout:
? bind base abc echo 0 # abc
? bind base ab,c echo 1 # ab
? bind base abc,d echo 2 # abc
? bind base ac,d echo 3 # ac
? bind base a,b,c echo 4
? bind base a,b,c,d echo 5
? bind base a,b,cc,dd echo 6 # cc and dd
bind-inter-key-timeout
[Option] Multi-key bind sequences do not time out by default.
If this variable is set, then the current key sequence is
forcefully terminated once the timeout (in milliseconds) trig-
gers. The value should be (maybe significantly) larger than
bind-inter-byte-timeout, but may not excess the maximum, too.
bsdcompat
(Boolean) Sets some cosmetical features to traditional BSD
style; has the same affect as setting askatend and all other
variables prefixed with `bsd'; it also changes the behaviour of
emptystart (which does not exist in BSD).
bsdflags (Boolean) Changes the letters shown in the first column of a
header summary to traditional BSD style.
bsdheadline
(Boolean) Changes the display of columns in a header summary to
traditional BSD style.
bsdmsgs (Boolean) Changes some informational messages to traditional
BSD style.
bsdorder (Boolean) Causes the `Subject:' field to appear immediately af-
ter the `To:' field in message headers and with the ~h COMMAND
ESCAPES.
build-cc, build-ld, build-os, build-rest
(Read-only) The build environment, including the compiler, the
linker, the operating system S-nail has been build for, usually
taken from uname(1) via `uname -s', and then lowercased, as
well as all the possibly interesting rest of the configuration
and build environment. This information is also available in
the verbose output of the command version.
charset-7bit
The value that should appear in the `charset=' parameter of
`Content-Type:' MIME header fields when no character set con-
version of the message data was performed. This defaults to
US-ASCII, and the chosen character set should be US-ASCII com-
patible.
charset-8bit
[Option] The default 8-bit character set that is used as an im-
plicit last member of the variable sendcharsets. This defaults
to UTF-8 if character set conversion capabilities are avail-
able, and to ISO-8859-1 otherwise (unless the operating system
environment is known to always and exclusively support UTF-8
locales), in which case the only supported character set is
ttycharset and this variable is effectively ignored.
charset-unknown-8bit
[Option] RFC 1428 specifies conditions when internet mail gate-
ways shall "upgrade" the content of a mail message by using a
character set with the name `unknown-8bit'. Because of the un-
classified nature of this character set S-nail will not be ca-
pable to convert this character set to any other character set.
If this variable is set any message part which uses the charac-
ter set `unknown-8bit' is assumed to really be in the character
set given in the value, otherwise the (final) value of
charset-8bit is used for this purpose.
This variable will also be taken into account if a MIME type
(see The mime.types files) of a MIME message part that uses the
`binary' character set is forcefully treated as text.
cmd The default value for the pipe command.
colour-disable
(Boolean)[Option] Forcefully disable usage of colours. Also
see the section Coloured display.
colour-pager
(Boolean)[Option] Whether colour shall be used for output that
is paged through PAGER. Note that pagers may need special com-
mand line options, for example less(1) requires the option -R
and lv(1) the option -c in order to support colours. Often do-
ing manual adjustments is unnecessary since S-nail may perform
adjustments dependent on the value of the environment variable
PAGER (see there for more).
contact-mail, contact-web
(Read-only) Addresses for contact per email and web, respec-
tively, for bug reports, suggestions, or anything else regard-
ing S-nail. The former can be used directly: `? eval mail
$contact-mail'.
content-description-forwarded-message,
content-description-quote-attachment,
content-description-smime-message,
content-description-smime-signature
[Option](partially) Strings which will be placed in according
`Content-Description:' headers if non-empty. They all have de-
fault values, for example `Forwarded message'.
crt In a(n interactive) terminal session, then if this valued vari-
able is set it will be used as a threshold to determine how
many lines the given output has to span before it will be dis-
played via the configured PAGER; Usage of the PAGER can be
forced by setting this to the value `0', setting it without a
value will deduce the current height of the terminal screen to
compute the threshold (see LINES, screen and stty(1)). [v15
behaviour may differ] At the moment this uses the count of
lines of the message in wire format, which, dependent on the
mime-encoding of the message, is unrelated to the number of
display lines. (The software is old and historically the rela-
tion was a given thing.)
customhdr
Define a set of custom headers to be injected into newly com-
posed or forwarded messages. A custom header consists of the
field name followed by a colon `:' and the field content body.
Standard header field names cannot be overwritten by a custom
header, with the exception of `Comments:' and `Keywords:'.
Different to the command line option -C the variable value is
interpreted as a comma-separated list of custom headers: to in-
clude commas in header bodies they need to become escaped with
reverse solidus `\'. Headers can be managed more freely in
Compose mode via ~^.
? set customhdr='Hdr1: Body1-1\, Body1-2, Hdr2: Body2'
datefield
Controls the appearance of the `%d' date and time format speci-
fication of the headline variable, that is used, for example,
when viewing the summary of headers. If unset, then the local
receiving date is used and displayed unformatted, otherwise the
message sending `Date:'. It is possible to assign a
strftime(3) format string and control formatting, but embedding
newlines via the `%n' format is not supported, and will result
in display errors. The default is `%Y-%m-%d %H:%M', and also
see datefield-markout-older.
datefield-markout-older
Only used in conjunction with datefield. Can be used to create
a visible distinction of messages dated more than a day in the
future, or older than six months, a concept comparable to the
-l option of the POSIX utility ls(1). If set to the empty
string, then the plain month, day and year of the `Date:' will
be displayed, but a strftime(3) format string to control for-
matting can be assigned. The default is `%Y-%m-%d'.
debug (Boolean) (Almost) Enter a debug-only sandbox mode which gener-
ates many log messages, disables the actual delivery of mes-
sages, and also implies norecord as well as nosave. Also see
verbose.
disposition-notification-send
(Boolean)[Option] Emit a `Disposition-Notification-To:' header
(RFC 3798) with the message. This requires the from variable
to be set.
dot (Boolean) When dot is set, a period `.' on a line by itself
during message input in (interactive or batch -#) Compose mode
will be treated as end-of-message (in addition to the normal
end-of-file condition). This behaviour is implied in posix
mode with a set ignoreeof.
dotlock-disable
(Boolean)[Option] Disable creation of dotlock files for MBOX
databases.
dotlock-ignore-error
[Obsolete](Boolean)[Option] Ignore failures when creating
dotlock files. Please use dotlock-disable instead.
editalong
If this variable is set then the editor is started automati-
cally when a message is composed in interactive mode. If the
value starts with the letter `v' then this acts as if ~v, oth-
erwise as if ~e (see COMMAND ESCAPES) had been specified. The
editheaders variable is implied for this automatically spawned
editor session.
editheaders
(Boolean) When a message is edited while being composed, its
header is included in the editable text.
emptystart
(Boolean) When entering interactive mode S-nail normally writes
"No mail for user" and exits immediately if a mailbox is empty
or does not exist. If this variable is set S-nail starts even
with an empty or non-existent mailbox (the latter behaviour
furtherly depends upon bsdcompat, though).
errexit (Boolean) Let each command with a non-0 exit status, including
every called macro which returns a non-0 status, cause a pro-
gram exit unless prefixed by ignerr (see Command modifiers).
This also affects COMMAND ESCAPES, but which use a different
modifier for ignoring the error. Please refer to the variable
? for more on this topic.
errors-limit
[Option] Maximum number of entries in the errors queue.
escape The first character of this value defines the escape character
for COMMAND ESCAPES in Compose mode. The default value is the
character tilde `~'. If set to the empty string, command es-
capes are disabled.
expandaddr
If unset only user name and email address recipients are al-
lowed On sending mail, and non-interactive mode. If set with-
out value all possible recipient types will be accepted. A
value is parsed as a comma-separated list of case-insensitive
strings, and if that contains `restrict' behaviour equals the
former except when in interactive mode or if COMMAND ESCAPES
were enabled via -~ or -#, in which case it equals the latter,
allowing all address types. `restrict' really acts like
`restrict,-all,+name,+addr', so care for ordering issues must
be taken.
Recipient types can be added and removed with a plus sign `+'
or hyphen-minus `-' prefix, respectively. By default invalid
or disallowed types are filtered out and cause a warning, hard
send errors need to be enforced by including `fail'. The value
`all' covers all types, `fcc' whitelists `Fcc:' header targets
regardless of other settings, `file' file targets (it includes
`fcc'), `pipe' command pipeline targets, `name' user names
still unexpanded after alias and mta-aliases processing and
thus left for expansion by the mta (invalid for the built-in
SMTP one), and `addr' network addresses. Targets are inter-
preted in the given order, so that `restrict,fail,+file,-all,
+addr' will cause hard errors for any non-network address re-
cipient address unless running interactively or having been
started with the option -~ or -#; in the latter case(s) any
type may be used.
User name receivers addressing valid local users can be ex-
panded to fully qualified network addresses (also see hostname)
by including `nametoaddr' in the list. Historically invalid
recipients were stripped off without causing errors, this can
be changed by making `failinvaddr' an entry of the list (it re-
ally acts like `failinvaddr,+addr'). Likewise, `domaincheck'
(really `domaincheck,+addr') compares address domain names
against a whitelist and strips off (`fail' for hard errors) ad-
dressees which fail this test; the domain name `localhost' and
the non-empty value of hostname (the real hostname otherwise)
are always whitelisted, expandaddr-domaincheck can be set to
extend this list. Finally some address providers (for example
-b, -c and all other command line recipients) will be evaluated
as if specified within dollar-single-quotes (see Shell-style
argument quoting) if the value list contains the string
`shquote'.
expandaddr-domaincheck
Can be set to a comma-separated list of domain names which
should be whitelisted for the evaluation of the `domaincheck'
mode of expandaddr. IDNA encoding is not automatically per-
formed, addrcodec can be used to prepare the domain (of an ad-
dress).
expandargv
Unless this variable is set additional mta (Mail-Transfer-
Agent) arguments from the command line, as can be given after a
-- separator, results in a program termination with failure
status. The same can be accomplished by using the special
(case-insensitive) value `fail'. A lesser strict variant is
the otherwise identical `restrict', which does accept such ar-
guments in interactive mode, or if tilde commands were enabled
explicitly by using one of the command line options -~ or -#.
The empty value will allow unconditional usage.
features (Read-only) String giving a list of optional features. Fea-
tures are preceded with a plus sign `+' if they are available,
with a hyphen-minus `-' otherwise. To ease substring matching
the string starts and ends with a comma. The output of the
command version includes this information in a more pleasant
output.
flipr (Boolean) This setting reverses the meanings of a set of reply
commands, turning the lowercase variants, which by default ad-
dress all recipients included in the header of a message
(reply, respond, followup) into the uppercase variants, which
by default address the sender only (Reply, Respond, Followup)
and vice versa.
folder The default path under which mailboxes are to be saved: file-
names that begin with the plus sign `+' will have the plus sign
replaced with the value of this variable if set, otherwise the
plus sign will remain unchanged when doing Filename
transformations; also see folder for more on this topic, and
know about standard imposed implications of outfolder. The
value supports a subset of transformations itself, and if the
non-empty value does not start with a solidus `/', then the
value of HOME will be prefixed automatically. Once the actual
value is evaluated first, the internal variable folder-resolved
will be updated for caching purposes.
folder-hook-FOLDER, folder-hook
Names a defined macro which will be called whenever a folder is
opened. The macro will also be invoked when new mail arrives,
but message lists for commands executed from the macro only in-
clude newly arrived messages then. localopts are activated by
default in a folder hook, causing the covered settings to be
reverted once the folder is left again.
The specialized form will override the generic one if `FOLDER'
matches the file that is opened. Unlike other folder specifi-
cations, the fully expanded name of a folder, without metachar-
acters, is used to avoid ambiguities. However, if the mailbox
resides under folder then the usual `+' specification is tried
in addition, so that if folder is "mail" (and thus relative to
the user's home directory) then /home/usr1/mail/sent will be
tried as `folder-hook-/home/usr1/mail/sent' first, but then
followed by `folder-hook-+sent'.
folder-resolved
(Read-only) Set to the fully resolved path of folder once that
evaluation has occurred; rather internal.
followup-to
(Boolean) Controls whether a `Mail-Followup-To:' header is gen-
erated when sending messages to known mailing lists. The user
as determined via from (or, if that contains multiple ad-
dresses, sender) will be placed in there if any list addressee
is not a subscribed list. Also see followup-to-honour and the
commands mlist, mlsubscribe, reply and Lreply.
followup-to-add-cc
(Boolean) Controls whether the user will be added to the mes-
sages' `Cc:' list in addition to placing an entry in
`Mail-Followup-To:' (see followup-to).
followup-to-honour
Controls whether a `Mail-Followup-To:' header is honoured when
group-replying to a message via reply or Lreply. This is a
quadoption; if set without a value it defaults to "yes", and
see followup-to.
forward-add-cc
(Boolean) Whether senders of messages forwarded via ~F, ~f, ~m,
~U or ~u shall be made members of the carbon copies `Cc:' list.
forward-as-attachment
(Boolean) Original messages are normally sent as inline text
with the forward command, and only the first part of a multi-
part message is included. With this setting enabled messages
are sent as unmodified MIME `message/rfc822' attachments with
all of their parts included.
forward-inject-head, forward-inject-tail
The strings to put before and after the text of a message with
the forward command, respectively. The former defaults to
`-------- Original Message --------\n'. Special format direc-
tives in these strings will be expanded if possible, and if so
configured the output will be folded according to quote-fold;
for more please refer to quote-inject-head. Injections will
not be performed by forward if the variable
forward-as-attachment is set -- the COMMAND ESCAPES ~F, ~f, ~M,
~m, ~U, ~u always inject.
from The address (or a list of addresses) to put into the `From:'
field of the message header, quoting RFC 5322: the author(s) of
the message, that is, the mailbox(es) of the person(s) or sys-
tem(s) responsible for the writing of the message. According
to that RFC setting the sender variable is required if from
contains more than one address. [v15 behaviour may differ]
Please expect automatic management of the from and sender rela-
tionship. Dependent on the context these addresses are handled
as if they were in the list of alternates.
If a file-based MTA is used, then from (or, if that contains
multiple addresses, sender) can nonetheless be used as the en-
velope sender address at the MTA protocol level (the RFC 5321
reverse-path), either via the -r command line option (without
argument; see there for more), or by setting r-option-implicit.
If the machine's hostname is not valid at the Internet (for ex-
ample at a dialup machine), then either this variable or
hostname ([v15-compat] a SMTP-based mta adds even more fine-
tuning capabilities with smtp-hostname) have to be set: if so
the message and MIME part related unique ID fields
`Message-ID:' and `Content-ID:' will be created (except when
disallowed by message-id-disable or stealthmua).
fullnames
(Boolean) Due to historical reasons comments and name parts of
email addresses are removed by default when sending mail, re-
plying to or forwarding a message. If this variable is set
such stripping is not performed.
fwdheading
[Obsolete] Predecessor of forward-inject-head.
header (Boolean) Causes the header summary to be written at startup
and after commands that affect the number of messages or the
order of messages in the current folder. Unless in posix mode
a header summary will also be displayed on folder changes. The
command line option -N can be used to set noheader.
headline A format string to use for the summary of headers. Format
specifiers in the given string start with a percent sign `%'
and may be followed by an optional decimal number indicating
the field width -- if that is negative, the field is to be
left-aligned. Names and addresses are subject to modifications
according to showname and showto. Valid format specifiers are:
`%%' A plain percent sign.
`%>' "Dotmark": a space character but for the current mes-
sage ("dot"), for which it expands to `>' (dependent
on headline-plain).
`%<' "Dotmark": a space character but for the current mes-
sage ("dot"), for which it expands to `<' (dependent
on headline-plain).
`%$' [Option] The spam score of the message, as has been
classified via the command spamrate. Shows only a
replacement character if there is no spam support.
`%a' Message attribute character (status flag); the actual
content can be adjusted by setting attrlist.
`%d' The date found in the `Date:' header of the message
when datefield is set (the default), otherwise the
date when the message was received. Formatting can
be controlled by assigning a strftime(3) format
string to datefield (and datefield-markout-older).
`%e' The indenting level in `thread'ed sort mode.
`%f' The address of the message sender.
`%i' The message thread tree structure. (Note that this
format does not support a field width, and honours
headline-plain.)
`%L' Mailing list status: is the addressee of the message
a known `l' (mlist) or `L' mlsubscribed mailing list?
The letter `P' announces the presence of a RFC 2369
`List-Post:' header, which makes a message a valuable
target of Lreply.
`%l' The number of lines of the message, if available.
`%m' Message number.
`%o' The number of octets (bytes) in the message, if
available.
`%S' Message subject (if any) in double quotes.
`%s' Message subject (if any).
`%t' The position in threaded/sorted order.
`%U' The value 0 except in an IMAP mailbox, where it ex-
pands to the UID of the message.
The default is `%>%a%m %-18f %16d %4l/%-5o %i%-s', or
`%>%a%m %20-f %16d %3l/%-5o %i%-S' if bsdcompat is set. Also
see attrlist, headline-plain and headline-bidi.
headline-bidi
Bidirectional text requires special treatment when displaying
headers, because numbers (in dates or for file sizes etc.) will
not affect the current text direction, in effect resulting in
ugly line layouts when arabic or other right-to-left text is to
be displayed. On the other hand only a minority of terminals
is capable to correctly handle direction changes, so that user
interaction is necessary for acceptable results. Note that ex-
tended host system support is required nonetheless, e.g., de-
tection of the terminal character set is one precondition; and
this feature only works in an Unicode (i.e., UTF-8) locale.
In general setting this variable will cause S-nail to encapsu-
late text fields that may occur when displaying headline (and
some other fields, like dynamic expansions in prompt) with spe-
cial Unicode control sequences; it is possible to fine-tune the
terminal support level by assigning a value: no value (or any
value other than `1', `2' and `3') will make S-nail assume that
the terminal is capable to properly deal with Unicode version
6.3, in which case text is embedded in a pair of U+2068 (FIRST
STRONG ISOLATE) and U+2069 (POP DIRECTIONAL ISOLATE) charac-
ters. In addition no space on the line is reserved for these
characters.
Weaker support is chosen by using the value `1' (Unicode 6.3,
but reserve the room of two spaces for writing the control se-
quences onto the line). The values `2' and `3' select Unicode
1.1 support (U+200E, LEFT-TO-RIGHT MARK); the latter again re-
serves room for two spaces in addition.
headline-plain
(Boolean) On Unicode (UTF-8) aware terminals enhanced graphical
symbols are used by default for certain entries of headline.
If this variable is set only basic US-ASCII symbols will be
used.
history-file
[Option] The (expandable) location of a permanent history file
for the MLE line editor (On terminal control and line editor).
Also see history-size.
history-gabby
[Option] Add more entries to the MLE history as is normally
done. A comma-separated list of case-insensitive strings can
be used to fine-tune which gabby entries shall be allowed. If
it contains `errors', erroneous commands will also be added.
`all' adds all optional entries, and is the fallback chattiness
identifier of on-history-addition.
history-gabby-persist
(Boolean)[Option] The history-gabby entries will not be saved
in persistent storage unless this variable is set. The knowl-
edge of whether a persistent entry was gabby is not lost. Also
see history-file.
history-size
[Option] Setting this variable imposes a limit on the number of
concurrent history entries. If set to the value 0 then no fur-
ther history entries will be added, and loading and incorpora-
tion of the history-file upon program startup can also be sup-
pressed by doing this. Runtime changes will not be reflected
before the history is saved or loaded (again).
hold (Boolean) This setting controls whether messages are held in
the system inbox, and it is set by default.
hostname Used instead of the value obtained from uname(3) and
getaddrinfo(3) as the hostname when expanding local addresses,
for example in `From:' (also see On sending mail, and non-
interactive mode, for expansion of addresses that have a valid
user-, but no domain name in angle brackets). If either of
from or this variable is set the message and MIME part related
unique ID fields `Message-ID:' and `Content-ID:' will be cre-
ated (except when disallowed by message-id-disable or
stealthmua). If the [Option]al IDNA support is available (see
idna-disable) variable assignment is aborted when a necessary
conversion fails.
Setting it to the empty string will cause the normal hostname
to be used, but nonetheless enables creation of said ID fields.
[v15-compat] in conjunction with the built-in SMTP mta
smtp-hostname also influences the results: one should produce
some test messages with the desired combination of hostname,
and/or from, sender etc. first.
idna-disable
(Boolean)[Option] Can be used to turn off the automatic conver-
sion of domain names according to the rules of IDNA (interna-
tionalized domain names for applications). Since the IDNA code
assumes that domain names are specified with the ttycharset
character set, an UTF-8 locale charset is required to represent
all possible international domain names (before conversion,
that is).
ifs The input field separator that is used ([v15 behaviour may dif-
fer] by some functions) to determine where to split input data.
1. Unsetting is treated as assigning the default value,
` \t\n'.
2. If set to the empty value, no field splitting will be
performed.
3. If set to a non-empty value, all whitespace charac-
ters are extracted and assigned to the variable
ifs-ws.
a. ifs-ws will be ignored at the beginning and end of
input. Diverging from POSIX shells default white-
space is removed in addition, which is owed to the
entirely different line content extraction rules.
b. Each occurrence of a character of ifs will cause
field-splitting, any adjacent ifs-ws characters will
be skipped.
ifs-ws (Read-only) Automatically deduced from the whitespace charac-
ters in ifs.
ignore (Boolean) Ignore interrupt signals from the terminal while en-
tering messages; instead echo them as `@' characters and dis-
card the current line.
ignoreeof
(Boolean) Ignore end-of-file conditions (`control-D') in
Compose mode on message input and in interactive command input.
If set an interactive command input session can only be left by
explicitly using one of the commands exit and quit, and message
input in compose mode can only be terminated by entering a pe-
riod `.' on a line by itself or by using the ~. COMMAND
ESCAPES; Setting this implies the behaviour that dot describes
in posix mode.
inbox If this is set to a non-empty string it will specify the user's
primary system mailbox, overriding MAIL and the system-depen-
dent default, and (thus) be used to replace `%' when doing
Filename transformations; also see folder for more on this
topic. The value supports a subset of transformations itself.
indentprefix
String used by the ~m, ~M and ~R COMMAND ESCAPES and by the
quote option for indenting messages, in place of the POSIX man-
dated default tabulator character `\t'. Also see quote-chars.
keep (Boolean) If set, an empty primary system mailbox file is not
removed. Note that, in conjunction with posix mode any empty
file will be removed unless this variable is set. This may im-
prove the interoperability with other mail user agents when us-
ing a common folder directory, and prevents malicious users
from creating fake mailboxes in a world-writable spool direc-
tory. [v15 behaviour may differ] Only local regular (MBOX)
files are covered, Maildir and other mailbox types will never
be removed, even if empty.
keep-content-length
(Boolean) When (editing messages and) writing MBOX mailbox
files S-nail can be told to keep the `Content-Length:' and
`Lines:' header fields that some MUAs generate by setting this
variable. Since S-nail does neither use nor update these non-
standardized header fields (which in itself shows one of their
conceptual problems), stripping them should increase interoper-
ability in between MUAs that work with with same mailbox files.
Note that, if this is not set but writebackedited, as below,
is, a possibly performed automatic stripping of these header
fields already marks the message as being modified. [v15 be-
haviour may differ] At some future time S-nail will be capable
to rewrite and apply an mime-encoding to modified messages, and
then those fields will be stripped silently.
keepsave (Boolean) When a message is saved it is usually discarded from
the originating folder when S-nail is quit. This setting
causes all saved message to be retained.
line-editor-cpl-word-breaks
[Option] List of bytes which are used by the mle-complete tabu-
lator completion to decide where word boundaries exist, by de-
fault `"'@=;|:' [v15 behaviour may differ] This mechanism is
yet restricted.
line-editor-disable
(Boolean) Turn off any line editing capabilities (from S-nails
POW, see On terminal control and line editor for more).
line-editor-no-defaults
(Boolean)[Option] Do not establish any default key binding.
log-prefix
Error log message prefix string (`s-nail: ').
mailbox-display
(Read-only) The name of the current mailbox (folder), possibly
abbreviated for display purposes.
mailbox-resolved
(Read-only) The fully resolved path of the current mailbox.
mailcap-disable
(Boolean)[Option] Turn off consideration of MIME type handlers
from, and implicit loading of The Mailcap files.
mailx-extra-rc
An additional startup file that is loaded as the last of the
Resource files. Use this file for commands that are not under-
stood by other POSIX mailx(1) implementations, i.e., mostly
anything which is not covered by Initial settings.
markanswered
(Boolean) When a message is replied to and this variable is
set, it is marked as having been answered. See the section
Message states.
mbox-fcc-and-pcc
(Boolean) By default all file and pipe message receivers (see
expandaddr) will be fed valid MBOX database entry message data
(see folder, mbox-rfc4155), and existing file targets will be-
come extended in compliance to RFC 4155. If this variable is
unset then a plain standalone RFC 5322 message will be written,
and existing file targets will be overwritten.
mbox-rfc4155
(Boolean) When opening MBOX mailbox databases, and in order to
achieve compatibility with old software, the very tolerant
POSIX standard rules for detecting message boundaries (so-
called `From_' lines) are used instead of the stricter rules
from the standard RFC 4155. This behaviour can be switched by
setting this variable.
This may temporarily be handy when S-nail complains about in-
valid `From_' lines when opening a MBOX: in this case setting
this variable and re-opening the mailbox in question may cor-
rect the result. If so, copying the entire mailbox to some
other file, as in `copy * SOME-FILE', will perform proper, all-
compatible `From_' quoting for all detected messages, resulting
in a valid MBOX mailbox. ([v15 behaviour may differ] The bet-
ter and non-destructive approach is to re-encode invalid mes-
sages, as if it would be created anew, instead of mangling the
`From_' lines; this requires the structural code changes of the
v15 rewrite.) Finally the variable can be unset again:
define mboxfix {
localopts yes; wysh set mbox-rfc4155;\
wysh File "${1}"; copy * "${2}"
}
call mboxfix /tmp/bad.mbox /tmp/good.mbox
memdebug (Boolean) Internal development variable. (Keeps memory debug
enabled even if debug is not set.)
message-id-disable
(Boolean) By setting this variable the generation of
`Message-ID:' and `Content-ID:' message and MIME part headers
can be completely suppressed, effectively leaving this task up
to the mta (Mail-Transfer-Agent) or the SMTP server. Note that
according to RFC 5321 a SMTP server is not required to add this
field by itself, so it should be ensured that it accepts mes-
sages without `Message-ID'.
message-inject-head
A string to put at the beginning of each new message, followed
by a newline. [Obsolete] The escape sequences tabulator `\t'
and newline `\n' are understood (use the wysh prefix when
setting the variable(s) instead).
message-inject-tail
A string to put at the end of each new message, followed by a
newline. [Obsolete] The escape sequences tabulator `\t' and
newline `\n' are understood (use the wysh prefix when setting
the variable(s) instead). Also see on-compose-leave.
metoo (Boolean) Usually, when an alias expansion contains the sender,
the sender is removed from the expansion. Setting this option
suppresses these removals. Note that a set metoo also causes a
`-m' option to be passed through to the mta (Mail-Transfer-
Agent); though most of the modern MTAs no longer document this
flag, no MTA is known which does not support it (for historical
compatibility).
mime-allow-text-controls
(Boolean) When sending messages, each part of the message is
MIME-inspected in order to classify the `Content-Type:' and
`Content-Transfer-Encoding:' (see mime-encoding) that is re-
quired to send this part over mail transport, i.e., a computa-
tion rather similar to what the file(1) command produces when
used with the `--mime' option.
This classification however treats text files which are encoded
in UTF-16 (seen for HTML files) and similar character sets as
binary octet-streams, forcefully changing any `text/plain' or
`text/html' specification to `application/octet-stream': If
that actually happens a yet unset charset MIME parameter is set
to `binary', effectively making it impossible for the receiving
MUA to automatically interpret the contents of the part.
If this variable is set, and the data was unambiguously identi-
fied as text data at first glance (by a `.txt' or `.html' file
extension), then the original `Content-Type:' will not be over-
written.
mime-alternative-favour-rich
(Boolean) If this variable is set then rich MIME alternative
parts (e.g., HTML) will be preferred in favour of included
plain text versions when displaying messages, provided that a
handler exists which produces output that can be (re)integrated
into S-nail's normal visual display.
mime-counter-evidence
Normally the `Content-Type:' field is used to decide how to
handle MIME parts. Some MUAs, however, do not use The
mime.types files (also see HTML mail and MIME attachments) or a
similar mechanism to correctly classify content, but specify an
unspecific MIME type (`application/octet-stream') even for
plain text attachments. If this variable is set then S-nail
will try to re-classify such MIME message parts, if possible,
for example via a possibly existing attachment filename. A
non-empty value may also be given, in which case a number is
expected, actually a carrier of bits, best specified as a bi-
nary value, like `0b1111'.
o If bit two is set (counting from 1, decimal 2) then the de-
tected mimetype will be carried along with the message and
be used for deciding which MIME handler is to be used, for
example; when displaying such a MIME part the part-info
will indicate the overridden content-type by showing a plus
sign `+'.
o If bit three is set (decimal 4) then the counter-evidence
is always produced and a positive result will be used as
the MIME type, even forcefully overriding the parts given
MIME type.
o If bit four is set (decimal 8) as a last resort the actual
content of `application/octet-stream' parts will be in-
spected, so that data which looks like plain text can be
treated as such. This mode is even more relaxed when data
is to be displayed to the user or used as a message quote
(data consumers which mangle data for display purposes,
which includes masking of control characters, for example).
mime-encoding
The MIME `Content-Transfer-Encoding' to use in outgoing text
messages and message parts, where applicable (7-bit clean text
messages are without an encoding if possible):
`8bit' (Or `8b'.) 8-bit transport effectively causes the
raw data be passed through unchanged, but may cause
problems when transferring mail messages over chan-
nels that are not ESMTP (RFC 1869) compliant. Also,
several input data constructs are not allowed by the
specifications and may cause a different transfer-en-
coding to be used. By established rules and popular
demand occurrences of `^From_' (see mbox-rfc4155)
will be MBOXO quoted (prefixed with greater-than sign
`>') instead of causing a non-destructive encoding
like `quoted-printable' to be chosen, unless context
(like message signing) requires otherwise.
`quoted-printable'
(Or `qp'.) Quoted-printable encoding is 7-bit clean
and has the property that ASCII characters are passed
through unchanged, so that an english message can be
read as-is; it is also acceptable for other single-
byte locales that share many characters with ASCII,
for example ISO-8859-1. The encoding will cause a
large overhead for messages in other character sets:
for example it will require up to twelve (12) bytes
to encode a single UTF-8 character of four (4) bytes.
It is the default encoding.
`base64' (Or `b64'.) This encoding is 7-bit clean and will
always be used for binary data. This encoding has a
constant input:output ratio of 3:4, regardless of the
character set of the input data it will encode three
bytes of input to four bytes of output. This trans-
fer-encoding is not human readable without performing
a decoding step.
mime-force-sendout
(Boolean)[Option] Whenever it is not acceptable to fail sending
out messages because of non-convertible character content this
variable may be set. It will, as a last resort, classify the
part content as `application/octet-stream'. Please refer to
the section Character sets for the complete picture of charac-
ter set conversion in S-nail.
mimetypes-load-control
Can be used to control which of The mime.types files are
loaded: if the letter `u' is part of the option value, then the
user's personal ~/.mime.types file will be loaded (if it ex-
ists); likewise the letter `s' controls loading of the system
wide /etc/mime.types; directives found in the user file take
precedence, letter matching is case-insensitive. If this vari-
able is not set S-nail will try to load both files. Incorpora-
tion of the S-nail-built-in MIME types cannot be suppressed,
but they will be matched last (the order can be listed via
mimetype).
More sources can be specified by using a different syntax: if
the value string contains an equals sign `=' then it is instead
parsed as a comma-separated list of the described letters plus
`f=FILENAME' pairs; the given filenames will be expanded and
loaded, and their content may use the extended syntax that is
described in the section The mime.types files. Directives
found in such files always take precedence (are prepended to
the MIME type cache).
mta Select an alternate Mail-Transfer-Agent by either specifying
the full pathname of an executable (a `file://' prefix may be
given), or [Option]ally a SMTP aka SUBMISSION protocol URL
[v15-compat]:
submissions://[user[:password]@]server[:port]
([no v15-compat]: `[smtp://]server[:port]'.) The default has
been chosen at compile time. MTA data transfers are always
performed in asynchronous child processes, and without supervi-
sion unless either the sendwait or the verbose variable is set.
Also see mta-bcc-ok. [Option]ally expansion of aliases(5) can
be performed by setting mta-aliases.
For testing purposes there is the `test' pseudo-MTA, which
dumps to standard output or optionally to a file, and honours
mbox-fcc-and-pcc:
$ echo text | s-nail -:/ -Smta=test -s ubject ex@am.ple
$ </dev/null s-nail -:/ -Smta=test://./xy ex@am.ple
For a file-based MTA it may be necessary to set mta-argv0 in in
order to choose the right target of a modern mailwrapper(8) en-
vironment. It will be passed command line arguments from sev-
eral possible sources: from the variable mta-arguments if set,
from the command line if given and the variable expandargv al-
lows their use. Argument processing of the MTA will be termi-
nated with a -- separator.
The otherwise occurring implicit usage of the following MTA
command line arguments can be disabled by setting the boolean
variable mta-no-default-arguments (which will also disable
passing -- to the MTA): -i (for not treating a line with only a
dot `.' character as the end of input), -m (shall the variable
metoo be set) and -v (if the verbose variable is set); in con-
junction with the -r command line option or r-option-implicit
-f as well as possibly -F will (not) be passed.
[Option]ally S-nail can send mail over SMTP aka SUBMISSION net-
work connections to a single defined smart host by setting this
variable to a SMTP or SUBMISSION URL (see On URL syntax and
credential lookup). An authentication scheme can be specified
via the variable chain smtp-auth. Encrypted network connec-
tions are [Option]ally available, the section Encrypted network
communication should give an overview and provide links to more
information on this. Note that with some mail providers it may
be necessary to set the smtp-hostname variable in order to use
a specific combination of from, hostname and mta. Network com-
munication socket timeouts are configurable via
socket-connect-timeout. All generated network traffic may be
proxied over a SOCKS socks-proxy, it can be logged by setting
verbose twice. The following SMTP variants may be used:
o The plain SMTP protocol (RFC 5321) that normally lives on
the server port 25 and requires setting the
smtp-use-starttls variable to enter a TLS encrypted session
state. Assign a value like [v15-compat]
`smtp://[user[:password]@]server[:port]' ([no v15-compat]
`smtp://server[:port]') to choose this protocol.
o The so-called SMTPS which is supposed to live on server
port 465 and is automatically TLS secured. Unfortunately
it never became a standardized protocol and may thus not be
supported by your hosts network service database - in fact
the port number has already been reassigned to other proto-
cols!
SMTPS is nonetheless a commonly offered protocol and thus
can be chosen by assigning a value like [v15-compat]
`smtps://[user[:password]@]server[:port]' ([no v15-compat]
`smtps://server[:port]'); due to the mentioned problems it
is usually necessary to explicitly specify the port as
`:465', however.
o The SUBMISSION protocol (RFC 6409) lives on server port 587
and is identically to the SMTP protocol from S-nail's point
of view; it requires setting smtp-use-starttls to enter a
TLS secured session state; e.g., [v15-compat]
`submission://[user[:password]@]server[:port]'.
o The SUBMISSIONS protocol (RFC 8314) that lives on server
port 465 and is TLS secured by default. It can be chosen
by assigning a value like [v15-compat]
`submissions://[user[:password]@]server[:port]'. Due to
the problems mentioned for SMTPS above and the fact that
SUBMISSIONS is new and a successor that lives on the same
port as the historical engineering mismanagement named
SMTPS, it is usually necessary to explicitly specify the
port as `:465'.
mta-aliases
[Option] If set to a path pointing to a text file in valid MTA
(Postfix) aliases(5) format, the file is loaded and cached
(manageable with mtaaliases), and henceforth plain `name' (see
expandaddr) message receiver names are recursively expanded as
a last expansion step, after the distribution lists which can
be created with alias. Constraints on aliases(5) content sup-
port: only local addresses (names) which are valid usernames
(`[a-z_][a-z0-9_-]*[$]?') are treated as expandable aliases,
and [v15 behaviour may differ] `:include:/file/name' directives
are not supported. By including `-name' in expandaddr it can
be asserted that only expanded names (mail addresses) are
passed through to the MTA.
mta-arguments
Arguments to pass through to a file-based mta (Mail-Transfer-
Agent), parsed according to Shell-style argument quoting into
an array of arguments which will be joined onto MTA options
from other sources, for example `? wysh set mta-arguments='-t
-X "/tmp/my log"''.
mta-no-default-arguments
(Boolean) Avoids passing standard command line options to a
file-based mta (please see there).
mta-no-receiver-arguments
(Boolean) By default all receiver addresses will be passed as
command line options to a file-based mta. Setting this vari-
able disables this behaviour to aid those MTAs which employ
special treatment of such arguments. Doing so can make it nec-
essary to pass a -t via mta-arguments, to testify the MTA that
it should use the passed message as a template.
mta-argv0
Many systems use a so-called mailwrapper(8) environment to en-
sure compatibility with sendmail(1). This works by inspecting
the name that was used to invoke the mail delivery system. If
this variable is set then the mailwrapper (the program that is
actually executed when calling the file-based mta) will treat
its contents as that name.
mta-bcc-ok
(Boolean) In violation of RFC 5322 some MTAs do not remove
`Bcc:' header lines from transported messages after having
noted the respective receivers for addressing purposes. (The
MTAs Exim and Courier for example require the command line op-
tion -t to enforce removal.) Unless this is set corresponding
receivers are addressed by protocol-specific means or MTA com-
mand line options only, the header itself is stripped before
being sent over the wire.
netrc-lookup-USER@HOST, netrc-lookup-HOST, netrc-lookup
(Boolean)[v15-compat][Option] Used to control usage of the
user's ~/.netrc file for lookup of account credentials, as doc-
umented in the section On URL syntax and credential lookup and
for the command netrc; the section The .netrc file documents
the file format. Also see netrc-pipe.
netrc-pipe
[v15-compat][Option] When ~/.netrc is loaded (see netrc and
netrc-lookup) then S-nail will read the output of a shell pipe
instead of the user's ~/.netrc file if this variable is set (to
the desired shell command). This can be used to, for example,
store ~/.netrc in encrypted form: `? set netrc-pipe='gpg -qd
~/.netrc.pgp''.
newfolders
[Option] If this variable has the value `maildir', newly cre-
ated local folders will be in Maildir instead of MBOX format.
newmail Checks for new mail in the current folder each time the prompt
is shown. A Maildir folder must be re-scanned to determine if
new mail has arrived. If this variable is set to the special
value `nopoll' then a Maildir folder will not be rescanned com-
pletely, but only timestamp changes are detected. Maildir
folders are [Option]al.
outfolder
(Boolean) Causes a non-absolute filename specified in record,
as well as the sender-based filenames of the Copy, Save,
Followup and followup commands to be interpreted relative to
the folder directory rather than relative to the current direc-
tory.
on-account-cleanup-ACCOUNT, on-account-cleanup
Macro hook which will be called once an account is left, as the
very last step before unrolling per-account localopts. This
hook is run even in case of fatal errors, including those gen-
erated by switching to the account as such, and it is advisable
to perform only absolutely necessary actions, like cleaning up
alternates, for example. The specialized form is used in
favour of the generic one if found.
on-compose-cleanup
Macro hook which will be called after the message has been sent
(or not, in case of failures), as the very last step before un-
rolling compose mode localopts. This hook is run even in case
of fatal errors, and it is advisable to perform only absolutely
necessary actions, like cleaning up alternates, for example.
For compose mode hooks that may affect the message content
please see on-compose-enter, on-compose-leave,
on-compose-splice. [v15 behaviour may differ] This hook exists
because alias, alternates, commandalias, shortcut, to name a
few, are neither covered by localopts nor by local: changes ap-
plied in compose mode will continue to be in effect thereafter.
on-compose-enter, on-compose-leave
Macro hooks which will be called once compose mode is entered,
and after composing has been finished, respectively; the exact
order of the steps taken is documented for ~., one of the
COMMAND ESCAPES. Context about the message being worked on can
be queried via digmsg. localopts are enabled for these hooks,
and changes on variables will be forgotten after the message
has been sent. on-compose-cleanup can be used to perform other
necessary cleanup steps.
Here is an example that injects a signature via
message-inject-tail; instead using on-compose-splice to simply
inject the file of desire via ~< or ~<! may be a better ap-
proach.
define t_ocl {
vput ! i cat ~/.mysig
if $? -eq 0
vput csop message-inject-tail trim-end $i
end
# Alternatively
readctl create ~/.mysig
if $? -eq 0
readall i
if $? -eq 0
vput csop message-inject-tail trim-end $i
end
readctl remove ~/.mysig
end
}
set on-compose-leave=t_ocl
on-compose-splice, on-compose-splice-shell
These hooks run once the normal compose mode is finished, but
before the on-compose-leave macro hook is called etc. Both
hooks will be executed in a subprocess, with their input and
output connected to S-nail such that they can act as if they
would be an interactive user. The difference in between them
is that the latter is a SHELL command, whereas the former is a
normal defined macro, but which is restricted to a small set of
commands (the verbose output of for example list will indicate
said capability). localopts are enabled for these hooks (in
the parent process), causing any setting to be forgotten after
the message has been sent; on-compose-cleanup can be used to
perform other cleanup as necessary.
During execution of these hooks S-nail will temporarily forget
whether it has been started in interactive mode, (a restricted
set of) COMMAND ESCAPES will always be available, and for guar-
anteed reproducibilities sake escape and ifs will be set to
their defaults. The compose mode command ~^ has been espe-
cially designed for scriptability (via these hooks). The first
line the hook will read on its standard input is the protocol
version of said command escape, currently "0 0 2": backward in-
compatible protocol changes have to be expected.
Care must be taken to avoid deadlocks and other false control
flow: if both involved processes wait for more input to happen
at the same time, or one does not expect more input but the
other is stuck waiting for consumption of its output, etc.
There is no automatic synchronization of the hook: it will not
be stopped automatically just because it, e.g., emits `~x'.
The hooks will however receive a termination signal if the par-
ent enters an error condition. [v15 behaviour may differ] Pro-
tection against and interaction with signals is not yet given;
it is likely that in the future these scripts will be placed in
an isolated session, which is signalled in its entirety as nec-
essary.
define ocs_signature {
read version
echo '~< ~/.mysig' # '~<! fortune pathtofortunefile'
}
set on-compose-splice=ocs_signature
wysh set on-compose-splice-shell=$'\
read version;\
printf "hello $version! Headers: ";\
echo \'~^header list\';\
read status result;\
echo "status=$status result=$result";\
'
define ocsm {
read version
echo Splice protocol version is $version
echo '~^h l'; read hl; vput csop es subs "${hl}" 0 1
if "$es" != 2
echoerr 'Cannot read header list'; echo '~x'; xit
endif
if "$hl" !%?case ' cc'
echo '~^h i cc "Diet is your <mirr.or>"'; read es;\
vput csop es substring "${es}" 0 1
if "$es" != 2
echoerr 'Cannot insert Cc: header'; echo '~x'
# (no xit, macro finishes anyway)
endif
endif
}
set on-compose-splice=ocsm
on-history-addition
This hook will be called if an entry is about to be added to
the history of the MLE, as documented in On terminal control
and line editor. It will be called with three arguments: the
first is the name of the input context (see bind), the second
is either an empty string or the matching history-gabby type,
and the third being the complete command line to be added. The
entry will not be added to history if the hook uses a non-0
return. [v15 behaviour may differ] A future version will give
the expanded command name as the third argument, followed by
the tokenized command line as parsed in the remaining argu-
ments, the first of which is the original unexpanded command
name; i.e., one may do `shift 4' and will then be able to ac-
cess the positional parameters as usual via *, #, 1 etc.
on-main-loop-tick
This hook will be called whenever the program's main event loop
is about to read the next input line. Note variable and other
changes it performs are not scoped as via localopts!
on-program-exit
This hook will be called when the program exits, whether via
exit or quit, or because the send mode is done. Note: this
runs late and so terminal settings etc. are already teared
down.
on-resend-cleanup
[v15 behaviour may differ] Identical to on-compose-cleanup, but
is only triggered by resend.
on-resend-enter
[v15 behaviour may differ] Identical to on-compose-enter, but
is only triggered by resend; currently there is no digmsg sup-
port, for example.
page (Boolean) If set, each message feed through the command given
for pipe is followed by a formfeed character `\f'.
password-USER@HOST, password-HOST, password
[v15-compat] Variable chain that sets a password, which is used
in case none has been given in the protocol and account-spe-
cific URL; as a last resort S-nail will ask for a password on
the user's terminal if the authentication method requires a
password. Specifying passwords in a startup file is generally
a security risk; the file should be readable by the invoking
user only.
password-USER@HOST
[no v15-compat] (see the chain above for [v15-compat]) Set the
password for `USER' when connecting to `HOST'. If no such
variable is defined for a host, the user will be asked for a
password on standard input. Specifying passwords in a startup
file is generally a security risk; the file should be readable
by the invoking user only.
piperaw (Boolean) Send messages to the pipe command without performing
MIME and character set conversions.
pipe-TYPE/SUBTYPE
When a MIME message part of type `TYPE/SUBTYPE' (case-insensi-
tive) is displayed or quoted, its text is filtered through the
value of this variable interpreted as a shell command. Note
that only parts which can be displayed inline as plain text
(see copiousoutput) are displayed unless otherwise noted, other
MIME parts will only be considered by and for the command
mimeview.
The special value question mark `?' forces interpretation of
the message part as plain text, for example `set
pipe-application/xml=?' will henceforth display XML "as is".
(The same could also be achieved by adding a MIME type marker
with the mimetype command. And [Option]ally MIME type handlers
may be defined via The Mailcap files -- these directives,
copiousoutput has already been used, should be referred to for
further documentation.
The question mark `?' can in fact be used as a trigger charac-
ter to adjust usage and behaviour of a following shell command
specification more thoroughly by appending more special charac-
ters which refer to further mailcap directives, for example the
following hypothetical command specification could be used:
? set pipe-X/Y='?!++=? vim ${MAILX_FILENAME_TEMPORARY}'
`*' The command produces plain text to be integrated in
S-nails output: copiousoutput.
`#' If set the handler will not be invoked when a message
is to be quoted, but only when it will be displayed:
x-mailx-noquote.
`&' Run the command asynchronously, i.e., without block-
ing S-nail: x-mailx-async. The standard output of
the command will go to /dev/null.
`!' The command must be run on an interactive terminal,
S-nail will temporarily release the terminal to it:
needsterminal.
`+' Request creation of a zero-sized temporary file, the
absolute pathname of which will be made accessible
via the environment variable
MAILX_FILENAME_TEMPORARY: x-mailx-tmpfile. If given
twice then the file will be unlinked automatically by
S-nail when the command loop is entered again at lat-
est: x-mailx-tmpfile-unlink; it is an error to use
automatic deletion in conjunction with x-mailx-async.
`=' Normally the MIME part content is passed to the han-
dler via standard input; if this flag is set then the
data will instead be written into
MAILX_FILENAME_TEMPORARY (x-mailx-tmpfile-fill), the
creation of which is implied; in order to cause auto-
matic deletion of the temporary file two plus signs
`++' still have to be used.
`?' To avoid ambiguities with normal shell command con-
tent another question mark can be used to forcefully
terminate interpretation of remaining characters.
(Any character not in this list will have the same
effect.)
Some information about the MIME part to be displayed is embed-
ded into the environment of the shell command:
MAILX_CONTENT The MIME content-type of the part, if
known, the empty string otherwise.
MAILX_CONTENT_EVIDENCE If mime-counter-evidence includes the
carry-around-bit (2), then this will
be set to the detected MIME content-
type; not only then identical to
MAILX_CONTENT otherwise.
MAILX_EXTERNAL_BODY_URL MIME parts of type
`message/external-body
access-type=url' will store the access
URL in this variable, it is empty oth-
erwise. URL targets should not be ac-
tivated automatically, without super-
vision.
MAILX_FILENAME The filename, if any is set, the empty
string otherwise.
MAILX_FILENAME_GENERATED
A random string.
MAILX_FILENAME_TEMPORARY
If temporary file creation has been
requested through the command prefix
this variable will be set and contain
the absolute pathname of the temporary
file.
pipe-EXTENSION
This is identical to pipe-TYPE/SUBTYPE except that `EXTENSION'
(normalized to lowercase using character mappings of the ASCII
charset) names a file extension, for example `xhtml'. Handlers
registered using this method take precedence.
pop3-auth-USER@HOST, pop3-auth-HOST, pop3-auth
[Option][v15-compat] Variable chain that sets the POP3 authen-
tication method. Supported are the default `plain', [v15-com-
pat] `oauthbearer' (see FAQ entry But, how about XOAUTH2 /
OAUTHBEARER?), as well as [v15-compat] `external' and
`externanon' for TLS secured connections which pass a client
certificate via tls-config-pairs. There may be the [Option]al
method [v15-compat] `gssapi'. `externanon' does not need any
user credentials, `external' and `gssapi' need a user, the re-
mains also require a password. `externanon' solely builds upon
the credentials passed via a client certificate, and is usually
the way to go since tested servers do not actually follow RFC
4422, and fail if additional credentials are actually passed.
Unless pop3-no-apop is set the `plain' method will [Option]ally
be replaced with APOP if possible (see there).
pop3-bulk-load-USER@HOST, pop3-bulk-load-HOST, pop3-bulk-load
(Boolean)[Option] When accessing a POP3 server S-nail loads the
headers of the messages, and only requests the message bodies
on user request. For the POP3 protocol this means that the
message headers will be downloaded twice. If this variable is
set then S-nail will download only complete messages from the
given POP3 server(s) instead.
pop3-keepalive-USER@HOST, pop3-keepalive-HOST, pop3-keepalive
[Option] POP3 servers close the connection after a period of
inactivity; the standard requires this to be at least 10 min-
utes, but practical experience may vary. Setting this variable
to a numeric value greater than `0' causes a `NOOP' command to
be sent each value seconds if no other operation is performed.
pop3-no-apop-USER@HOST, pop3-no-apop-HOST, pop3-no-apop
(Boolean)[Option] Unless this variable is set the MD5 based
`APOP' authentication method will be used instead of a chosen
`plain' pop3-auth when connecting to a POP3 server that adver-
tises support. The advantage of `APOP' is that only a single
packet is sent for the user/password tuple. (Originally also
that the password is not sent in clear text over the wire, but
for one MD5 does not any longer offer sufficient security, and
then today transport is almost ever TLS secured.) Note that
pop3-no-apop-HOST requires [v15-compat].
pop3-use-starttls-USER@HOST, pop3-use-starttls-HOST, pop3-use-starttls
(Boolean)[Option] Causes S-nail to issue a `STLS' command to
make an unencrypted POP3 session TLS encrypted. This function-
ality is not supported by all servers, and is not used if the
session is already encrypted by the POP3S method. Note that
pop3-use-starttls-HOST requires [v15-compat].
posix (Boolean) This flag enables POSIX mode, which changes behaviour
of S-nail where that deviates from standardized behaviour. It
is automatically squared with the environment variable
POSIXLY_CORRECT, changing the one will adjust the other. The
following behaviour is covered and enforced by this mechanism:
o In non-interactive mode, any error encountered while load-
ing resource files during program startup will cause a pro-
gram exit, whereas in interactive mode such errors will
stop loading of the currently loaded (stack of) file(s,
i.e., recursively). These exits can be circumvented on a
per-command base by using ignerr, one of the Command
modifiers, for each command which shall be allowed to fail.
o alternates will replace the list of alternate addresses in-
stead of appending to it. In addition alternates will only
be honoured for any sort of message reply, and for aliases.
o The variable inserting COMMAND ESCAPES ~A, ~a, ~I and ~i
will expand embedded character sequences `\t' horizontal
tabulator and `\n' line feed. [v15 behaviour may differ]
For compatibility reasons this step will always be per-
formed.
o Reading in messages via ~f (COMMAND ESCAPES) will use the
`type' not the `forward' headerpick selection.
o Upon changing the active folder no summary of headers will
be displayed even if header is set.
o Setting ignoreeof implies the behaviour described by dot.
o The variable keep is extended to cover any empty mailbox,
not only empty primary system mailboxes: they will be re-
moved when they are left in empty state otherwise.
print-alternatives
(Boolean) When a MIME message part of type
`multipart/alternative' is displayed and it contains a subpart
of type `text/plain', other parts are normally discarded. Set-
ting this variable causes all subparts to be displayed, just as
if the surrounding part was of type `multipart/mixed'.
prompt The string used as a prompt in interactive mode. Whenever the
variable is evaluated the value is treated as if specified
within dollar-single-quotes (see Shell-style argument quoting).
This (post-assignment, i.e., second) expansion can be used to
embed status information, for example ?, !, account or
mailbox-display.
In order to embed characters which should not be counted when
calculating the visual width of the resulting string, enclose
the characters of interest in a pair of reverse solidus escaped
brackets: `\[\E[0m\]'; a slot for coloured prompts is also
available with the [Option]al command colour. Prompting may be
prevented by setting this to the null string (aka `set
noprompt').
prompt2 This string is used for secondary prompts, but is otherwise
identical to prompt. The default is `.. '.
quiet (Boolean) Suppresses the printing of the version when first in-
voked.
quote If set messages processed by variants of followup and reply
will start with the original message, lines of which prefixed
by indentprefix, taking into account quote-chars and
quote-fold. No headers will be quoted when set without value
or for `noheading', for `headers' the `type' headerpick selec-
tion will be included in the quote, `allbodies' embeds the
(body) contents of all MIME parts, and `allheaders' also in-
cludes all headers. The quoted message will be enclosed by the
expansions of quote-inject-head and quote-inject-tail. Also
see quote-add-cc, quote-as-attachment and ~Q, one of the
COMMAND ESCAPES.
quote-add-cc
(Boolean) Whether senders of messages quoted via ~Q shall be
made members of the carbon copies `Cc:' list.
quote-as-attachment
(Boolean) Add the original message in its entirety as a
`message/rfc822' MIME attachment when replying to a message.
Note this works regardless of the setting of quote.
quote-chars
Can be set to a string consisting of non-whitespace ASCII char-
acters which shall be treated as quotation leaders, the default
being `>|}:'.
quote-fold
[Option] Can be set in addition to indentprefix, and creates a
more fancy quotation in that leading quotation characters
(quote-chars) are compressed and overlong lines are folded.
quote-fold can be set to either one, two or three (space sepa-
rated) numeric values, which are interpreted as the maximum
(goal) and the minimum line length, respectively, in a spirit
rather equal to the fmt(1) program, but line- instead of para-
graph-based. The third value is used as the maximum line
length instead of the first if no better break point can be
found; it is ignored unless it is larger than the minimum and
smaller than the maximum. If not set explicitly the minimum
will reflect the goal algorithmically. The goal cannot be
smaller than the length of indentprefix plus some additional
pad; necessary adjustments take place silently.
quote-inject-head, quote-inject-tail
The strings to put before and after the text of a quoted mes-
sage, if non-empty, and respectively. The former defaults to
`%f wrote:\n\n'. Special format directives will be expanded if
possible, and if so configured the output will be folded ac-
cording to quote-fold. Format specifiers in the given strings
start with a percent sign `%' and expand values of the original
message, unless noted otherwise. Note that names and addresses
are not subject to the setting of showto. Valid format speci-
fiers are:
`%%' A plain percent sign.
`%a' The address(es) of the sender(s).
`%d' The date found in the `Date:' header of the message
when datefield is set (the default), otherwise the
date when the message was received. Formatting can
be controlled by assigning a strftime(3) format
string to datefield (and datefield-markout-older).
`%f' The full name(s) (name and address, as given) of the
sender(s).
`%i' The `Message-ID:'.
`%n' The real name(s) of the sender(s) if there is one and
showname allows usage, the address(es) otherwise.
`%r' The senders real name(s) if there is one, the ad-
dress(es) otherwise.
r-option-implicit
(Boolean) Setting this option evaluates the contents of from
(or, if that contains multiple addresses, sender) and passes
the results onto the used (file-based) MTA as described for the
-r option (empty argument case).
recipients-in-cc
(Boolean) When doing a reply, the original `From:' and `To:' as
well as addressees which possibly came in via `Reply-To:' and
`Mail-Followup-To:' are by default merged into the new `To:'.
If this variable is set a sensitive algorithm tries to place in
`To:' only the sender of the message being replied to, others
are placed in `Cc:'.
record Unless this variable is defined, no copies of outgoing mail
will be saved. If defined it gives the pathname, subject to
the usual Filename transformations, of a folder where all new,
replied-to or forwarded messages are saved: when saving to this
folder fails the message is not sent, but instead saved to
DEAD. The standard defines that relative (fully expanded)
paths are to be interpreted relative to the current directory
(cwd), to force interpretation relative to folder outfolder
needs to be set in addition.
record-files
(Boolean) If this variable is set the meaning of record will be
extended to cover messages which target only file and pipe re-
cipients (see expandaddr). These address types will not appear
in recipient lists unless add-file-recipients is also set.
record-resent
(Boolean) If this variable is set the meaning of record will be
extended to also cover the resend and Resend commands.
reply-in-same-charset
(Boolean) If this variable is set S-nail first tries to use the
same character set of the original message for replies. If
this fails, the mechanism described in Character sets is evalu-
ated as usual.
reply-strings
Can be set to a comma-separated list of (case-insensitive ac-
cording to ASCII rules) strings which shall be recognized in
addition to the built-in strings as `Subject:' reply message
indicators - built-in are `Re:', which is mandated by RFC 5322,
as well as the german `Aw:', `Antw:', and the `Wg:' which often
has been seen in the wild; I.e., the separating colon has to be
specified explicitly.
reply-to A list of addresses to put into the `Reply-To:' field of the
message header. Members of this list are handled as if they
were in the alternates list.
replyto [Obsolete] Variant of reply-to.
reply-to-honour
Controls whether a `Reply-To:' header is honoured when replying
to a message via reply or Lreply. This is a quadoption; if set
without a value it defaults to "yes".
reply-to-swap-in
Standards like DKIM and (in conjunction with) DMARC caused many
Mailing lists to use sender address rewriting in the style of
`Name via List <list@address>', where the original sender ad-
dress often being placed in `Reply-To:'. If this is set and a
`Reply-To:' exists, and consists of only one addressee (!),
then that is used in place of the pretended sender. This works
independently from reply-to-honour. The optional value, a
comma-separated list of strings, offers more fine-grained con-
trol on when swapping shall be used; for now supported is
mlist, here swapping occurs if the sender is a mailing-list as
defined by mlist.
rfc822-body-from_
(Boolean) This variable can be used to force displaying a so-
called `From_' line for messages that are embedded into an en-
velope mail via the `message/rfc822' MIME mechanism, for more
visual convenience, also see mbox-rfc4155.
save (Boolean) Enable saving of (partial) messages in DEAD upon in-
terrupt or delivery error.
screen The number of lines that represents a "screenful" of lines,
used in headers summary display, from searching, message
topline display and scrolling via z. If this variable is not
set S-nail falls back to a calculation based upon the detected
terminal window size and the baud rate: the faster the termi-
nal, the more will be shown. Overall screen dimensions and
pager usage is influenced by the environment variables COLUMNS
and LINES and the variable crt.
searchheaders
(Boolean) Expand message list specifiers in the form `/x:y' to
all messages containing the substring "y" in the header field
`x'. The string search is case insensitive.
sendcharsets
[Option] A comma-separated list of character set names that can
be used in outgoing internet mail. The value of the variable
charset-8bit is automatically appended to this list of charac-
ter sets. If no character set conversion capabilities are com-
piled into S-nail then the only supported charset is
ttycharset. Also see sendcharsets-else-ttycharset and refer to
the section Character sets for the complete picture of charac-
ter set conversion in S-nail.
sendcharsets-else-ttycharset
(Boolean)[Option] If this variable is set, but sendcharsets is
not, then S-nail acts as if sendcharsets had been set to the
value of the variable ttycharset. In effect this combination
passes through the message data in the character set of the
current locale encoding: therefore mail message text will be
(assumed to be) in ISO-8859-1 encoding when send from within a
ISO-8859-1 locale, and in UTF-8 encoding when send from within
an UTF-8 locale.
The 8-bit fallback charset-8bit never comes into play as
ttycharset is implicitly assumed to be 8-bit and capable to
represent all files the user may specify (as is the case when
no character set conversion support is available in S-nail and
the only supported character set is ttycharset, see Character
sets). This might be a problem for scripts which use the sug-
gested `LC_ALL=C' setting, since in this case the character set
is US-ASCII by definition, so that it is better to also over-
ride ttycharset, then; and/or do something like the following
in the resource file:
# Avoid ASCII "propagates to 8-bit" when scripting
\if ! t && "$LC_ALL" != C && "$LC_CTYPE" != C
\set sendcharsets-else-ttycharset
\end
sender An address that is put into the `Sender:' field of outgoing
messages, quoting RFC 5322: the mailbox of the agent responsi-
ble for the actual transmission of the message. This field
should normally not be used unless the from field contains more
than one address, on which case it is required. [v15 behaviour
may differ] Please expect automatic management of the from and
sender relationship. Dependent on the context this address is
handled as if it were in the list of alternates. Also see -r,
r-option-implicit.
sendmail [Obsolete] Predecessor of mta.
sendmail-arguments
[Obsolete] Predecessor of mta-arguments.
sendmail-no-default-arguments
[Obsolete](Boolean) Predecessor of mta-no-default-arguments.
sendmail-progname
[Obsolete] Predecessor of mta-argv0.
sendwait Sending messages to the chosen mta or to command-pipe receivers
(see On sending mail, and non-interactive mode) will be per-
formed asynchronously. This means that only startup errors of
the respective program will be recognizable, but no delivery
errors. Also, no guarantees can be made as to when the respec-
tive program will actually run, as well as to when they will
have produced output.
If this variable is set then child program exit is waited for,
and its exit status code is used to decide about success. Re-
marks: in conflict with the POSIX standard this variable is
built-in to be initially set. Another difference is that it
can have a value, which is interpreted as a comma-separated
list of case-insensitive strings naming specific subsystems for
which synchronousness shall be ensured (only). Possible values
are `mta' for mta delivery, and `pcc' for command-pipe re-
ceivers.
showlast (Boolean) This setting causes S-nail to start at the last mes-
sage instead of the first one when opening a mail folder, as
well as with from and headers.
showname (Boolean) Causes S-nail to use the sender's real name instead
of the plain address in the header field summary and in message
specifications.
showto (Boolean) Causes the recipient of the message to be shown in
the header summary if the message was sent by the user.
Sign The value backing ~A, one of the COMMAND ESCAPES. Also see
message-inject-tail, on-compose-leave and on-compose-splice.
sign The value backing ~a, one of the COMMAND ESCAPES. Also see
message-inject-tail, on-compose-leave and on-compose-splice.
signature
[Obsolete] Please use on-compose-splice or
on-compose-splice-shell or on-compose-leave and (if necessary)
message-inject-tail instead!
skipemptybody
(Boolean) If an outgoing message has an empty first or only
message part, do not send, but discard it, successfully (also
see the command line option -E).
smime-ca-dir, smime-ca-file
[Option] Specify the location of trusted CA certificates in PEM
(Privacy Enhanced Mail) for the purpose of verification of
S/MIME signed messages. tls-ca-dir documents the necessary
preparation steps to use the former. The set of CA certifi-
cates which are built into the TLS library can be explicitly
turned off by setting smime-ca-no-defaults, and further fine-
tuning is possible via smime-ca-flags.
smime-ca-flags
[Option] Can be used to fine-tune behaviour of the X509 CA cer-
tificate storage, and the certificate verification that is
used. The actual values and their meanings are documented for
tls-ca-flags.
smime-ca-no-defaults
(Boolean)[Option] Do not load the default CA locations that are
built into the used to TLS library to verify S/MIME signed mes-
sages.
smime-cipher-USER@HOST, smime-cipher
[Option] Specifies the cipher to use when generating S/MIME en-
crypted messages (for the specified account). RFC 5751 man-
dates a default of `aes128' (AES-128 CBC). Possible values are
(case-insensitive and) in decreasing cipher strength: `aes256'
(AES-256 CBC), `aes192' (AES-192 CBC), `aes128' (AES-128 CBC),
`des3' (DES EDE3 CBC, 168 bits; default if `aes128' is not
available) and `des' (DES CBC, 56 bits).
The actually available cipher algorithms depend on the crypto-
graphic library that S-nail uses. [Option] Support for more
cipher algorithms may be available through dynamic loading via
EVP_get_cipherbyname(3) (OpenSSL) if S-nail has been compiled
to support this.
smime-crl-dir
[Option] Specifies a directory that contains files with CRLs in
PEM format to use when verifying S/MIME messages.
smime-crl-file
[Option] Specifies a file that contains a CRL in PEM format to
use when verifying S/MIME messages.
smime-encrypt-USER@HOST
[Option] If this variable is set, messages send to the given
receiver are encrypted before sending. The value of the vari-
able must be set to the name of a file that contains a certifi-
cate in PEM format.
If a message is sent to multiple recipients, each of them for
whom a corresponding variable is set will receive an individu-
ally encrypted message; other recipients will continue to re-
ceive the message in plain text unless the
smime-force-encryption variable is set. It is recommended to
sign encrypted messages, i.e., to also set the smime-sign vari-
able. content-description-smime-message will be inspected for
messages which become encrypted.
smime-force-encryption
(Boolean)[Option] Causes S-nail to refuse sending unencrypted
messages.
smime-sign
(Boolean)[Option] S/MIME sign outgoing messages with the user's
(from) private key and include the users certificate as a MIME
attachment. Signing a message enables a recipient to verify
that the sender used a valid certificate, that the email ad-
dresses in the certificate match those in the message header
and that the message content has not been altered. It does not
change the message text, and people will be able to read the
message as usual. content-description-smime-signature will be
inspected. Also see smime-sign-cert, smime-sign-include-certs
and smime-sign-digest.
smime-sign-cert-USER@HOST, smime-sign-cert
[Option] Points to a file in PEM format. For the purpose of
signing and decryption this file needs to contain the user's
private key, followed by his certificate.
For message signing `USER@HOST' is always derived from the
value of from (or, if that contains multiple addresses,
sender). For the purpose of encryption the recipients public
encryption key (certificate) is expected; the command certsave
can be used to save certificates of signed messages (the sec-
tion Signed and encrypted messages with S/MIME gives some de-
tails). This mode of operation is usually driven by the spe-
cialized form.
When decrypting messages the account is derived from the recip-
ient fields (`To:' and `Cc:') of the message, which are
searched for addresses for which such a variable is set.
S-nail always uses the first address that matches, so if the
same message is sent to more than one of the user addresses us-
ing different encryption keys, decryption might fail.
Password-encrypted keys may be used for signing and decryption.
Automated password lookup is possible via the "pseudo-hosts"
`USER@HOST.smime-cert-key' for the private key, and
`USER@HOST.smime-cert-cert' for the certificate stored in the
same file. For example, the hypothetical address
`bob@exam.ple' could be driven with a private key / certificate
pair path defined in smime-sign-cert-bob@exam.ple, and the
needed passwords would then be looked up as
`bob@exam.ple.smime-cert-key' and
`bob@exam.ple.smime-cert-cert'. When decrypting the value of
from will be tried as a fallback to provide the necessary
`USER@HOST'. To include intermediate certificates, use
smime-sign-include-certs. The possible password sources are
documented in On URL syntax and credential lookup.
smime-sign-digest-USER@HOST, smime-sign-digest
[Option] Specifies the message digest to use when signing
S/MIME messages. Please remember that for this use case
`USER@HOST' refers to the variable from (or, if that contains
multiple addresses, sender). The available algorithms depend
on the used cryptographic library, but at least one usable
built-in algorithm is ensured as a default. If possible the
standard RFC 5751 will be violated by using `SHA512' instead of
the mandated `SHA1' due to security concerns. This variable is
ignored for very old (released before 2010) cryptographic li-
braries which do not offer the necessary interface: it will be
logged if that happened.
S-nail will try to add built-in support for the following mes-
sage digests, names are case-insensitive: `BLAKE2b512',
`BLAKE2s256', `SHA3-512', `SHA3-384', `SHA3-256', `SHA3-224',
as well as the widely available `SHA512', `SHA384', `SHA256',
`SHA224', and the proposed insecure `SHA1', finally `MD5'.
More digests may [Option]ally be available through dynamic
loading via the OpenSSL function EVP_get_digestbyname(3).
smime-sign-include-certs-USER@HOST, smime-sign-include-certs
[Option] If used, this is supposed to a consist of a comma-sep-
arated list of files, each of which containing a single cer-
tificate in PEM format to be included in the S/MIME message in
addition to the smime-sign-cert certificate. This can be used
to include intermediate certificates of the certificate author-
ity, in order to allow the receiver's S/MIME implementation to
perform a verification of the entire certificate chain, start-
ing from a local root certificate, over the intermediate cer-
tificates, down to the smime-sign-cert. Even though top level
certificates may also be included in the chain, they will not
be used for the verification on the receiver's side.
For the purpose of the mechanisms involved here, `USER@HOST'
refers to the content of the internal variable from (or, if
that contains multiple addresses, sender). The pseudo-host
`USER@HOST.smime-include-certs' will be used for performing
password lookups for these certificates, shall they have been
given one, therefore the lookup can be automated via the mecha-
nisms described in On URL syntax and credential lookup.
smime-sign-message-digest-USER@HOST, smime-sign-message-digest
[Obsolete][Option] Predecessor(s) of smime-sign-digest.
smtp [Obsolete][Option] To use the built-in SMTP transport, specify
a SMTP URL in mta. [v15 behaviour may differ] For compatibil-
ity reasons a set smtp is used in preference of mta.
smtp-auth-USER@HOST, smtp-auth-HOST, smtp-auth
[Option] Variable chain that controls the SMTP mta authentica-
tion method, possible values are `none' ([no v15-compat] de-
fault), `plain' ([v15-compat] default), `login', [v15-compat]
`oauthbearer' (see FAQ entry But, how about XOAUTH2 /
OAUTHBEARER?) as well as [v15-compat] `external' and
`externanon' for TLS secured connections which pass a client
certificate via tls-config-pairs. There may be the [Option]al
methods `cram-md5' and `gssapi'. `none' and `externanon' do
not need any user credentials, `external' and `gssapi' require
a user name, and all other methods require a user name and a
password. `externanon' solely builds upon the credentials
passed via a client certificate, and is usually the way to go
since tested servers do not actually follow RFC 4422 aka RFC
4954, and fail if additional credentials are passed. Also see
mta. Note that smtp-auth-HOST is [v15-compat]. ([no v15-com-
pat] Requires smtp-auth-password and smtp-auth-user. Note for
smtp-auth-USER@HOST: may override dependent on sender address
in the variable from.)
smtp-auth-password
[Option][no v15-compat] Sets the global fallback password for
SMTP authentication. If the authentication method requires a
password, but neither smtp-auth-password nor a matching
smtp-auth-password-USER@HOST can be found, S-nail will ask for
a password on the user's terminal.
smtp-auth-password-USER@HOST
[no v15-compat] Overrides smtp-auth-password for specific val-
ues of sender addresses, dependent upon the variable from.
smtp-auth-user
[Option][no v15-compat] Sets the global fallback user name for
SMTP authentication. If the authentication method requires a
user name, but neither smtp-auth-user nor a matching
smtp-auth-user-USER@HOST can be found, S-nail will ask for a
user name on the user's terminal.
smtp-auth-user-USER@HOST
[no v15-compat] Overrides smtp-auth-user for specific values of
sender addresses, dependent upon the variable from.
smtp-hostname
[Option][v15-compat] Normally S-nail uses the variable from to
derive the necessary `USER@HOST' information in order to issue
a `MAIL FROM:<>' SMTP mta command. Setting smtp-hostname can
be used to use the `USER' from the SMTP account (mta or the
user variable chain) and the given `HOST' (hostname if the
empty string is given, or the local hostname as a last resort).
This often allows using an address that is itself valid but
hosted by a provider other than from which (in from) the mes-
sage is sent. Setting this variable also influences generated
`Message-ID:' and `Content-ID:' header fields. If the [Op-
tion]al IDNA support is available (see idna-disable) variable
assignment is aborted when a necessary conversion fails.
smtp-use-starttls-USER@HOST, smtp-use-starttls-HOST, smtp-use-starttls
(Boolean)[Option] Causes S-nail to issue a `STARTTLS' command
to make an SMTP mta session TLS encrypted, i.e., to enable
transport layer security.
socket-connect-timeout
[Option] A positive number that defines the timeout to wait for
establishing a socket connection before forcing ^ERR-TIMEDOUT.
socks-proxy-USER@HOST, socks-proxy-HOST, socks-proxy
[Option] If set to the URL of a SOCKS5 server then all network
activities are proxied through it, except for the single DNS
name lookup necessary to resolve the proxy URL (unnecessary
when given an already resolved IP address). It is automati-
cally squared with the environment variable SOCKS5_PROXY,
changing the one will adjust the other. This example creates a
local SOCKS5 proxy on port 10000 that forwards to the machine
`HOST' (with identity `USER'), and from which actual network
traffic happens:
$ ssh -D 10000 USER@HOST
$ s-nail -Ssocks-proxy=[socks5://]localhost:10000
# or =localhost:10000; no local DNS: =127.0.0.1:10000
spam-interface
[Option] In order to use any of the spam-related commands (like
spamrate) the desired spam interface must be defined by setting
this variable. Please refer to the manual section Handling
spam for the complete picture of spam handling in S-nail. All
or none of the following interfaces may be available:
`spamc' Interaction with spamc(1) from the spamassassin(1)
(SpamAssassin: http://spamassassin.apache.org) suite.
Different to the generic filter interface S-nail will
automatically add the correct arguments for a given
command and has the necessary knowledge to parse the
program's output. A default value for spamc-command
will have been compiled into the S-nail binary if
spamc(1) has been found in PATH during compilation.
Shall it be necessary to define a specific connection
type (rather than using a configuration file for
that), the variable spamc-arguments can be used as in
for example `-d server.example.com -p 783'. It is
also possible to specify a per-user configuration via
spamc-user. Note that this interface does not in-
spect the `is-spam' flag of a message for the command
spamforget.
`filter' generic spam filter support via freely configurable
hooks. This interface is meant for programs like
bogofilter(1) and requires according behaviour in re-
spect to the hooks' exit status for at least the com-
mand spamrate (`0' meaning a message is spam, `1' for
non-spam, `2' for unsure and any other return value
indicating a hard error); since the hooks can include
shell code snippets diverting behaviour can be inter-
cepted as necessary. The hooks are spamfilter-ham,
spamfilter-noham, spamfilter-nospam, spamfilter-rate
and spamfilter-spam; the manual section Handling spam
contains examples for some programs. The process en-
vironment of the hooks will have the variable
MAILX_FILENAME_GENERATED set. Note that spam score
support for spamrate is not supported unless the [Op-
tion]tional regular expression support is available
and the spamfilter-rate-scanscore variable is set.
spam-maxsize
[Option] Messages that exceed this size will not be passed
through to the configured spam-interface. If unset or 0, the
default of 420000 bytes is used.
spamc-command
[Option] The path to the spamc(1) program for the `spamc'
spam-interface. Note that the path is not expanded, but used
"as is". A fallback path will have been compiled into the
S-nail binary if the executable had been found during compila-
tion.
spamc-arguments
[Option] Even though S-nail deals with most arguments for the
`spamc' spam-interface automatically, it may at least sometimes
be desirable to specify connection-related ones via this vari-
able, for example `-d server.example.com -p 783'.
spamc-user
[Option] Specify a username for per-user configuration files
for the `spamc' spam-interface. If this is set to the empty
string then S-nail will use the name of the current user.
spamfilter-ham, spamfilter-noham, spamfilter-nospam, spamfilter-rate,
spamfilter-spam
[Option] Command and argument hooks for the `filter'
spam-interface. The manual section Handling spam contains ex-
amples for some programs.
spamfilter-rate-scanscore
[Option] Because of the generic nature of the `filter'
spam-interface spam scores are not supported for it by default,
but if the [Option]nal regular expression support is available
then setting this variable can be used to overcome this re-
striction. It is interpreted as follows: first a number (dig-
its) is parsed that must be followed by a semicolon `;' and an
extended regular expression. Then the latter is used to parse
the first output line of the spamfilter-rate hook, and, in case
the evaluation is successful, the group that has been specified
via the number is interpreted as a floating point scan score.
ssl-ca-dir-USER@HOST, ssl-ca-dir-HOST, ssl-ca-dir, ssl-ca-file-USER@HOST,
ssl-ca-file-HOST, ssl-ca-file
[Obsolete][Option] Predecessors of tls-ca-file, tls-ca-dir.
ssl-ca-flags-USER@HOST, ssl-ca-flags-HOST, ssl-ca-flags
[Obsolete][Option] Predecessor of tls-ca-flags.
ssl-ca-no-defaults-USER@HOST, ssl-ca-no-defaults-HOST, ssl-ca-no-defaults
[Obsolete](Boolean)[Option] Predecessor of tls-ca-no-defaults.
ssl-cert-USER@HOST, ssl-cert-HOST, ssl-cert
[Obsolete][Option] Please use the Certificate slot of
tls-config-pairs.
ssl-cipher-list-USER@HOST, ssl-cipher-list-HOST, ssl-cipher-list
[Obsolete][Option] Please use the CipherString slot of
tls-config-pairs.
ssl-config-file
[Obsolete][Option] Predecessor of tls-config-file.
ssl-config-module-USER@HOST, ssl-config-module-HOST, ssl-config-module
[Obsolete][Option] Predecessor of tls-config-module.
ssl-config-pairs-USER@HOST, ssl-config-pairs-HOST, ssl-config-pairs
[Obsolete][Option] Predecessor of tls-config-pairs.
ssl-crl-dir, ssl-crl-file
[Obsolete][Option] Predecessors of tls-crl-dir, tls-crl-file.
ssl-curves-USER@HOST, ssl-curves-HOST, ssl-curves
[Obsolete][Option] Please use the Curves slot of
tls-config-pairs.
ssl-features
[Obsolete][Option](Read-only) Predecessor of tls-features.
ssl-key-USER@HOST, ssl-key-HOST, ssl-key
[Obsolete][Option] Please use the PrivateKey slot of
tls-config-pairs.
ssl-method-USER@HOST, ssl-method-HOST, ssl-method
[Obsolete][Option] Please use the Protocol slot of
tls-config-pairs.
ssl-protocol-USER@HOST, ssl-protocol-HOST, ssl-protocol
[Obsolete][Option] Please use the Protocol slot of
tls-config-pairs.
ssl-rand-file
[Obsolete][Option] Predecessor of tls-rand-file.
ssl-verify-USER@HOST, ssl-verify-HOST, ssl-verify
[Obsolete][Option] Predecessor of tls-verify.
stealthmua
If only set without an assigned value, then this setting in-
hibits the generation of the `Message-ID:', `Content-ID:' and
`User-Agent:' header fields that include obvious references to
S-nail. There are two pitfalls associated with this: First,
the message id of outgoing messages is not known anymore. Sec-
ond, an expert may still use the remaining information in the
header to track down the originating mail user agent. If set
to the value `noagent', then the mentioned `Message-ID:' and
`Content-ID:' suppression does not occur.
system-mailrc
(Read-only) The compiled in path of the system wide initializa-
tion file one of the Resource files: s-nail.rc.
termcap ([Option]) This specifies a comma-separated list of Terminal
Information Library (libterminfo, -lterminfo) and/or Termcap
Access Library (libtermcap, -ltermcap) capabilities (see On
terminal control and line editor, escape commas with reverse
solidus `\') to be used to overwrite or define entries. Note
this variable will only be queried once at program startup and
can thus only be specified in resource files or on the command
line. It will always be inspected, regardless of whether
features denotes termcap/terminfo library support via
`,+termcap,'.
String capabilities form `cap=value' pairs and are expected un-
less noted otherwise. Numerics have to be notated as
`cap#number' where the number is expected in normal decimal no-
tation. Finally, booleans do not have any value but indicate a
true or false state simply by being defined or not; this indeed
means that S-nail does not support undefining an existing bool-
ean. String capability values will undergo some expansions be-
fore use: for one notations like `^LETTER' stand for
`control-LETTER', and for clarification purposes `\E' can be
used to specify `escape' (the control notation `^[' could lead
to misreadings when a left bracket follows, which it does for
the standard CSI sequence); finally three letter octal se-
quences, as in `\061', are supported. To specify that a termi-
nal supports 256-colours, and to define sequences that home the
cursor and produce an audible bell, one might write:
? set termcap='Co#256,home=\E[H,bel=^G'
The following terminal capabilities are or may be meaningful
for the operation of the built-in line editor or S-nail in gen-
eral:
am auto_right_margin: boolean which indicates if the
right margin needs special treatment; the xenl capa-
bility is related, for more see COLUMNS. This capa-
bility is only used when backed by library support.
clear or cl
clear_screen: clear the screen and home cursor.
(Will be simulated via ho plus cd.)
colors or Co
max_colors: numeric capability specifying the maximum
number of colours. Note that S-nail does not actu-
ally care about the terminal beside that, but always
emits ANSI / ISO 6429 escape sequences; also see
colour.
cr carriage_return: move to the first column in the cur-
rent row. The default built-in fallback is `\r'.
cub1 or le
cursor_left: move the cursor left one space (non-de-
structively). The default built-in fallback is `\b'.
cuf1 or nd
cursor_right: move the cursor right one space (non-
destructively). The default built-in fallback is
`\E[C', which is used by most terminals. Less often
occur `\EC' and `\EOC'.
ed or cd clr_eos: clear the screen.
el or ce clr_eol: clear to the end of line. (Will be simu-
lated via ch plus repetitions of space characters.)
home or ho
cursor_home: home cursor.
hpa or ch
column_address: move the cursor (to the given column
parameter) in the current row. (Will be simulated
via cr plus nd.)
rmcup or te / smcup or ti
exit_ca_mode and enter_ca_mode, respectively: exit
and enter the alternative screen ca-mode, effectively
turning S-nail into a fullscreen application. This
must be enabled explicitly by setting
termcap-ca-mode.
smkx or ks / rmkx or ke
keypad_xmit and keypad_local, respectively: enable
and disable the keypad. This is always enabled if
available, because it seems even keyboards without
keypads generate other key codes for, e.g., cursor
keys in that case, and only if enabled we see the
codes that we are interested in.
xenl or xn
eat_newline_glitch: boolean which indicates whether a
newline written in the last column of an
auto_right_margin indicating terminal is ignored.
With it the full terminal width is available even on
autowrap terminals. This will be inspected even
without `,+termcap,' features.
Many more capabilities which describe key-sequences are docu-
mented for bind.
termcap-ca-mode
[Option] Allow usage of the exit_ca_mode and enter_ca_mode
termcapabilities in order to enter an alternative exclusive
screen, the so-called ca-mode; this usually requires special
configuration of the PAGER, also dependent on the value of crt.
Note this variable will only be queried once at program startup
and can thus only be specified in resource files or on the com-
mand line.
termcap-disable
[Option] Disable any interaction with a terminal control li-
brary. If set only some generic fallback built-ins and possi-
bly the content of termcap describe the terminal to S-nail.
Note this variable will only be queried once at program startup
and can thus only be specified in resource files or on the com-
mand line.
tls-ca-dir-USER@HOST, tls-ca-dir-HOST, tls-ca-dir, tls-ca-file-USER@HOST,
tls-ca-file-HOST, tls-ca-file
[Option] Directory and file, respectively, for pools of trusted
CA certificates in PEM (Privacy Enhanced Mail) format, for the
purpose of verification of TLS server certificates. Concurrent
use is possible, the file is loaded once needed first, the di-
rectory lookup is performed anew as a last resort whenever nec-
essary. The CA certificate pool built into the TLS library can
be disabled via tls-ca-no-defaults, further fine-tuning is pos-
sible via tls-ca-flags. The directory search requires special
filename conventions, please see
SSL_CTX_load_verify_locations(3) and verify(1) (or
c_rehash(1)).
tls-ca-flags-USER@HOST, tls-ca-flags-HOST, tls-ca-flags
[Option] Can be used to fine-tune behaviour of the X509 CA cer-
tificate storage, and the certificate verification that is used
(also see tls-verify). The value is expected to consist of a
comma-separated list of configuration directives, with any in-
tervening whitespace being ignored. The directives directly
map to flags that can be passed to X509_STORE_set_flags(3),
which are usually defined in a file openssl/x509_vfy.h, and the
availability of which depends on the used TLS library version:
a directive without mapping is ignored (error log subject to
debug). Directives currently understood (case-insensitively)
include:
no-alt-chains
If the initial chain is not trusted, do not attempt
to build an alternative chain. Setting this flag
will make OpenSSL certificate verification match that
of older OpenSSL versions, before automatic building
and checking of alternative chains has been imple-
mented; also see trusted-first.
no-check-time
Do not check certificate/CRL validity against current
time.
partial-chain
By default partial, incomplete chains which cannot be
verified up to the chain top, a self-signed root cer-
tificate, will not verify. With this flag set, a
chain succeeds to verify if at least one signing cer-
tificate of the chain is in any of the configured
trusted stores of CA certificates. The OpenSSL man-
ual page SSL_CTX_load_verify_locations(3) gives some
advise how to manage your own trusted store of CA
certificates.
strict Disable workarounds for broken certificates.
trusted-first
Try building a chain using issuers in the trusted
store first to avoid problems with server-sent legacy
intermediate certificates. Newer versions of OpenSSL
support alternative chain checking and enable it by
default, resulting in the same behaviour; also see
no-alt-chains.
tls-ca-no-defaults-USER@HOST, tls-ca-no-defaults-HOST, tls-ca-no-defaults
(Boolean)[Option] Do not load the default CA locations that are
built into the used to TLS library to verify TLS server cer-
tificates.
tls-config-file
[Option] If this variable is set CONF_modules_load_file(3) (if
announced via `,+modules-load-file,' in tls-features) is used
to allow resource file based configuration of the TLS library.
This happens once the library is used first, which may also be
early during startup (logged with verbose)! If a non-empty
value is given then the given file, after performing Filename
transformations, will be used instead of the TLS libraries
global default, and it is an error if the file cannot be
loaded. The application name will always be passed as
`s-nail'. Some TLS libraries support application-specific con-
figuration via resource files loaded like this, please see
tls-config-module.
tls-config-module-USER@HOST, tls-config-module-HOST, tls-config-module
[Option] If file based application-specific configuration via
tls-config-file is available, announced as `,+ctx-config,' by
tls-features, indicating availability of SSL_CTX_config(3),
then, it becomes possible to use a central TLS configuration
file for all programs, including s-nail, for example
# Register a configuration section for s-nail
s-nail = mailx_master
# The top configuration section creates a relation
# in between dynamic SSL configuration and an actual
# program specific configuration section
[mailx_master]
ssl_conf = mailx_tls_config
# And that program specific configuration section now
# can map diverse tls-config-module names to sections,
# as in: tls-config-module=account_xy
[mailx_tls_config]
account_xy = mailx_account_xy
account_yz = mailx_account_yz
[mailx_account_xy]
MinProtocol = TLSv1.2
Curves=P-521
[mailx_account_yz]
CipherString = TLSv1.2:!aNULL:!eNULL:
MinProtocol = TLSv1.1
Options = Bugs
tls-config-pairs-USER@HOST, tls-config-pairs-HOST, tls-config-pairs
[Option] The value of this variable chain will be interpreted
as a comma-separated list of directive/value pairs. Directives
and values need to be separated by equals signs `=', any white-
space surrounding pair members is removed. Keys are (usually)
case-insensitive. Different to when placing these pairs in a
tls-config-module section of a tls-config-file, commas `,' need
to be escaped with a reverse solidus `\' when included in
pairs; also different: if the equals sign `=' is preceded with
an asterisk `*' Filename transformations will be performed on
the value; it is an error if these fail. Unless proper support
is announced by tls-features (`,+conf-ctx,') only the keys be-
low are supported, otherwise the pairs will be used directly as
arguments to the function SSL_CONF_cmd(3).
Certificate Filename of a TLS client certificate (chain) re-
quired by some servers. Fallback support via
SSL_CTX_use_certificate_chain_file(3). Filename
transformations are performed. PrivateKey will
be set to the same value if not initialized ex-
plicitly. Some services support so-called
`external' authentication if a TLS client cer-
tificate was successfully presented during con-
nection establishment ("connecting is
authenticating").
CipherString A list of ciphers for TLS connections, see
ciphers(1). By default no list of ciphers is
set, resulting in a Protocol-specific list of ci-
phers (the protocol standards define lists of ac-
ceptable ciphers; possibly cramped by the used
TLS library). Fallback support via
SSL_CTX_set_cipher_list(3).
Ciphersuites A list of ciphers used for TLSv1.3 connections,
see ciphers(1). These will be joined onto the
list of ciphers from CipherString. Available if
tls-features announces `,+ctx-set-ciphersuites,',
as necessary via SSL_CTX_set_ciphersuites(3).
Curves A list of supported elliptic curves, if applica-
ble. By default no curves are set. Fallback
support via SSL_CTX_set1_curves_list(3), if
available.
MaxProtocol, MinProtocol
The maximum and minimum supported TLS versions,
respectively. Available if tls-features an-
nounces `,+ctx-set-maxmin-proto,', as necessary
via SSL_CTX_set_max_proto_version(3) and
SSL_CTX_set_min_proto_version(3); these fallbacks
use an internal parser which understands the
strings `SSLv3', `TLSv1', `TLSv1.1', `TLSv1.2',
`TLSv1.3', and the special value `None', which
disables the given limit.
Options Various flags to set. Fallback via
SSL_CTX_set_options(3), in which case any other
value but (exactly) `Bugs' results in an error.
PrivateKey Filename of the private key in PEM format of a
TLS client certificate. If unset, the value of
Certificate is used. Filename transformations
are performed. Fallback via
SSL_CTX_use_PrivateKey_file(3).
Protocol The used TLS protocol. If tls-features announces
`,+conf-ctx,' or `ctx-set-maxmin-proto' then us-
ing MaxProtocol and MinProtocol is preferable.
Fallback is SSL_CTX_set_options(3), driven via an
internal parser which understands the strings
`SSLv3', `TLSv1', `TLSv1.1', `TLSv1.2',
`TLSv1.3', and the special value `ALL'. Multiple
protocols may be given as a comma-separated list,
any whitespace is ignored, an optional plus sign
`+' prefix enables, a hyphen-minus `-' prefix
disables a protocol, so that `-ALL, TLSv1.2' en-
ables only the TLSv1.2 protocol.
tls-crl-dir, tls-crl-file
[Option] Specify a directory / a file, respectively, that con-
tains a CRL in PEM format to use when verifying TLS server cer-
tificates.
tls-features
[Option](Read-only) This expands to a comma-separated list of
the TLS library identity and optional features. To ease sub-
string matching the string starts and ends with a comma. Cur-
rently supported identities are `libressl' (LibreSSL) ,
`libssl-0x30000' (OpenSSL v3.0.0 series), `libssl-0x10100'
(OpenSSL v1.1.x series) and `libssl-0x10000' (elder OpenSSL se-
ries, other clones). Optional features are preceded with a
plus sign `+' when available, and with a hyphen-minus `-' oth-
erwise.
Currently known features are `conf-ctx' (tls-config-pairs),
`ctx-config' (tls-config-module), `ctx-set-ciphersuites'
(Ciphersuites slot of tls-config-pairs), `ctx-set-maxmin-proto'
(tls-config-pairs), `modules-load-file' (tls-config-file), and
`tls-rand-file' (tls-rand-file).
tls-fingerprint-USER@HOST, tls-fingerprint-HOST, tls-fingerprint
[Option] It is possible to replace the verification of the con-
nection peer certificate against the entire local pool of CAs
(for more see Encrypted network communication) with the compar-
ison against a precalculated certificate message digest, the
so-called fingerprint, to be specified as the used
tls-fingerprint-digest. This fingerprint can for example be
calculated with `tls fingerprint HOST'.
tls-fingerprint-digest-USER@HOST, tls-fingerprint-digest-HOST,
tls-fingerprint-digest
[Option] The message digest to be used when creating TLS cer-
tificate fingerprints, the defaults, if available, in test or-
der, being `BLAKE2s256', `SHA256'. For the complete list of
digest algorithms refer to smime-sign-digest.
tls-rand-file
[Option] If tls-features announces `,+tls-rand-file,' then this
will be queried to find a file with random entropy data which
can be used to seed the P(seudo)R(andom)N(umber)G(enerator),
see RAND_load_file(3). The default filename
(RAND_file_name(3), normally ~/.rnd) will be used if this vari-
able is not set or empty, or if the Filename transformations
fail. Shall seeding the PRNG have been successful,
RAND_write_file(3) will be called to update the entropy. Re-
marks: libraries which do not announce this feature seed the
PRNG by other means.
tls-verify-USER@HOST, tls-verify-HOST, tls-verify
[Option] Variable chain that sets the action to be performed if
an error occurs during TLS server certificate validation
against the specified or default trust stores tls-ca-dir,
tls-ca-file, or the TLS library built-in defaults (unless usage
disallowed via tls-ca-no-defaults), and as fine-tuned via
tls-ca-flags. Valid (case-insensitive) values are `strict'
(fail and close connection immediately), `ask' (ask whether to
continue on standard input), `warn' (show a warning and con-
tinue), `ignore' (do not perform validation). The default is
`ask'.
toplines If defined, gives the number of lines of a message to be dis-
played with the command top; if unset, the first five lines are
printed, if set to 0 the variable screen is inspected. If the
value is negative then its absolute value will be used for un-
signed right shifting (see vexpr) the screen height.
topsqueeze
(Boolean) If set then the top command series will strip adja-
cent empty lines and quotations.
ttycharset
The character set of the terminal S-nail operates on, and the
one and only supported character set that S-nail can use if no
character set conversion capabilities have been compiled into
it, in which case it defaults to ISO-8859-1. Otherwise it de-
faults to UTF-8. Sufficient locale support provided the de-
fault will be preferably deduced from the locale environment if
that is set (for example LC_CTYPE, see there for more); runtime
locale changes will be reflected by ttycharset except during
the program startup phase and if -S had been used to freeze the
given value. Refer to the section Character sets for the com-
plete picture about character sets.
typescript-mode
(Boolean) A special multiplex variable that disables all vari-
ables and settings which result in behaviour that interferes
with running S-nail in script(1); it sets colour-disable,
line-editor-disable and (before startup completed only)
termcap-disable. Unsetting it does not restore the former
state of the covered settings.
umask For a safe-by-default policy the process file mode creation
mask umask(2) will be set to `0077' on program startup after
the resource files have been loaded, and unless this variable
is set. By assigning this an empty value the active setting
will not be changed, otherwise the given value will be made the
new file mode creation mask. Child processes inherit the file
mode creation mask of their parent.
user-HOST, user
[v15-compat] Variable chain that sets a global fallback user
name, used in case none has been given in the protocol and ac-
count-specific URL. This variable defaults to the name of the
user who runs S-nail.
v15-compat
Enable upward compatibility with S-nail version 15.0 in respect
to which configuration options are available and how they are
handled. If set to a non-empty value the command modifier wysh
is implied and thus enforces Shell-style argument quoting over
Old-style argument quoting for all commands which support both.
This manual uses [v15-compat] and [no v15-compat] to refer to
the new and the old way of doing things, respectively.
verbose Verbose mode enables logging of informational context messages.
Historically a (Boolean) variable, this can either be set mul-
tiple times (what the command line option -v uses), or be as-
signed a numeric value in order to increase verbosity. Assign-
ing the value 0 disables verbosity and thus (almost) equals
unset. The maximum number is 3. Also see debug.
version, version-date, version-hexnum, version-major, version-minor,
version-update
(Read-only) S-nail version information: the first variable is a
string with the complete version identification, the second the
release date in ISO 8601 notation without time. The third is a
32-bit hexadecimal number with the upper 8 bits storing the ma-
jor, followed by the minor and update version numbers which oc-
cupy 12 bits each. The latter three variables contain only
decimal digits: the major, minor and update version numbers.
The output of the command version will include this informa-
tion.
writebackedited
If this variable is set messages modified using the edit or
visual commands are written back to the current folder when it
is quit; it is only honoured for writable folders in MBOX for-
mat, though. Note that the editor will be pointed to the raw
message content in that case, i.e., neither MIME decoding nor
decryption will have been performed, and proper mbox-rfc4155
`From_' quoting of newly added or edited content is also left
as an exercise to the user.
ENVIRONMENT
The term "environment variable" should be considered an indication that
these variables are either standardized as vivid parts of process envi-
ronments, or that they are commonly found in there. The process environ-
ment is inherited from the sh(1) once S-nail is started, and unless oth-
erwise explicitly noted handling of the following variables transparently
integrates into that of the INTERNAL VARIABLES from S-nail's point of
view. This means they can be managed via set and unset, causing auto-
matic program environment updates (to be inherited by newly created child
processes).
In order to integrate other environment variables equally they need to be
imported (linked) with the command environ. This command can also be
used to set and unset non-integrated environment variables from scratch,
sufficient system support provided. The following example, applicable to
a POSIX shell, sets the COLUMNS environment variable for S-nail only, and
beforehand exports the EDITOR in order to affect any further processing
in the running shell:
$ EDITOR="vim -u ${HOME}/.vimrc"
$ export EDITOR
$ COLUMNS=80 s-nail -R
COLUMNS The user's preferred width in column positions for the terminal
screen. Queried and used once on program startup in interac-
tive or batch (-#) mode, actively managed for child processes
and the MLE (see On terminal control and line editor) in inter-
active mode thereafter. Non-interactive mode always uses, and
the fallback default is a compile-time constant, by default 80
columns. If in batch mode COLUMNS and LINES are both set but
not both are usable (empty, not a number, or 0) at program
startup, then the real terminal screen size will be (tried to
be) determined once. (Normally the sh(1) manages these vari-
ables, and unsets them for pipe specifications etc.)
DEAD The name of the (mailbox) folder to use for saving aborted mes-
sages if save is set; this defaults to ~/dead.letter. If the
variable debug is set no output will be generated, otherwise
the contents of the file will be replaced. Except shell globs
Filename transformations (also see folder) will be performed.
EDITOR Pathname of the text editor to use for the edit command and ~e
(see COMMAND ESCAPES); VISUAL is used for a more display ori-
ented editor.
HOME The user's home directory. This variable is only used when it
resides in the process environment. The calling user's home
directory will be used instead if this directory does not ex-
ist, is not accessible or cannot be read; it will always be
used for the root user. (No test for being writable is per-
formed to allow usage by non-privileged users within read-only
jails, but dependent on settings this directory is a default
write target for, for example, DEAD, MBOX and more.)
LC_ALL, LC_CTYPE, LANG
[Option] The (names in lookup order of the) locale(7) (and / or
see setlocale(3)) which indicates the used Character sets.
Runtime changes trigger automatic updates of the entire locale
system, which includes updating ttycharset (except during
startup if the variable has been frozen via -S).
LINES The user's preferred number of lines for the terminal screen.
The behaviour is as described for COLUMNS, yet the compile-time
constant used in non-interactive mode and as a fallback de-
faults to 24 (lines).
LISTER Pathname of the directory lister to use in the folders command
when operating on local mailboxes. Default is ls(1) (path
search through SHELL).
LOGNAME Upon startup S-nail will actively ensure that this variable
refers to the name of the user who runs S-nail, in order to be
able to pass a verified name to any newly created child
process.
MAIL Is used as the user's primary system mailbox unless inbox is
set. If the environmental fallback is also not set, a built-in
compile-time default is used. This is assumed to be an abso-
lute pathname.
MAILCAPS [Option] Override the default path search of The Mailcap files:
any existing file therein will be loaded in sequence, appending
any content to the list of MIME type handler directives. The
RFC 1524 standard imposed default value is assigned otherwise:
`~/.mailcap:/etc/mailcap:/usr/etc/mailcap:
/usr/local/etc/mailcap'. (The default value is a compile-time
[Option].)
MAILRC Is used as a startup file instead of ~/.mailrc if set. In or-
der to avoid side-effects from configuration files scripts
should either set this variable to /dev/null or the -: command
line option should be used.
MAILX_NO_SYSTEM_RC
If this variable is set then reading of s-nail.rc (aka
system-mailrc) at startup is inhibited, i.e., the same effect
is achieved as if S-nail had been started up with the option -:
(and according argument) or -n. This variable is only used
when it resides in the process environment.
MBOX The name of the user's secondary mailbox file. A logical sub-
set of the special Filename transformations (also see folder)
are supported. The default is ~/mbox. Traditionally this MBOX
is used as the file to save messages from the primary system
mailbox that have been read. Also see Message states.
NETRC [v15-compat][Option] This variable overrides the default loca-
tion of the user's ~/.netrc file.
PAGER Pathname of the program to use for backing the command more,
and when the crt variable enforces usage of a pager for output.
The default paginator is more(1) (path search through SHELL).
S-nail inspects the contents of this variable: if its contains
the string "less" then a non-existing environment variable LESS
will be set to `Ri', likewise for "lv" LV will optionally be
set to `-c'. Also see colour-pager.
PATH A colon-separated list of directories that is searched by the
shell when looking for commands, for example
`/bin:/usr/bin:/usr/local/bin'.
POSIXLY_CORRECT
This environment entry is automatically squared with posix.
SHELL The shell to use for the commands !, shell, the ~! COMMAND
ESCAPES and when starting subprocesses. A default shell is
used if this environment variable is not defined.
SOCKS5_PROXY
This environment entry is automatically squared with
socks-proxy.
SOURCE_DATE_EPOCH
Specifies a time in seconds since the Unix epoch (1970-01-01)
to be used in place of the current time. This variable is
looked up upon program startup, and its existence will switch
S-nail to a reproducible mode (https://reproducible-builds.org)
which uses deterministic random numbers, a special fixated
pseudo LOGNAME and more. This operation mode is used for de-
velopment and by software packagers. [v15 behaviour may dif-
fer] Currently an invalid setting is only ignored, rather than
causing a program abortion.
$ SOURCE_DATE_EPOCH=`date +%s` s-nail
TERM [Option] The terminal type for which output is to be prepared.
For extended colour and font control please refer to Coloured
display, and for terminal management in general to On terminal
control and line editor.
TMPDIR Except for the root user this variable defines the directory
for temporary files to be used instead of /tmp (or the given
compile-time constant) if set, existent, accessible as well as
read- and writable. This variable is only used when it resides
in the process environment, but S-nail will ensure at startup
that this environment variable is updated to contain a usable
temporary directory.
USER Identical to LOGNAME (see there), but this variable is not
standardized, should therefore not be used, and is only cor-
rected if already set.
VISUAL Pathname of the text editor to use for the visual command and
~v (see COMMAND ESCAPES); EDITOR is used for a less display
oriented editor.
FILES
~/.mailcap, /etc/mailcap
[Option] Personal and system-wide MIME type handler definition
files, see The Mailcap files. (The shown names are part of the
RFC 1524 standard search path MAILCAPS.)
~/.mailrc, s-nail.rc
User-specific and system-wide files giving initial commands,
the Resource files. (The used filenames come from MAILRC and
system-mailrc, respectively.)
~/mbox The default value for MBOX.
~/.mime.types, /etc/mime.types
Personal and system-wide MIME types, see The mime.types files.
~/.netrc [v15-compat][Option] The default location of the user's .netrc
file - the section The .netrc file documents the file format.
The used path can be set via NETRC.
/dev/null
The data sink null(4).
~/.rnd [Option] Possible location for persistent random entropy seed
storage, see tls-rand-file.
Resource files
Upon startup S-nail reads in several resource files, in order:
s-nail.rc
System wide initialization file (system-mailrc). Reading of
this file can be suppressed, either by using the -: (and ac-
cording argument) or -n command line options, or by setting the
ENVIRONMENT variable MAILX_NO_SYSTEM_RC.
~/.mailrc
File giving initial commands. A different file can be chosen
by setting the ENVIRONMENT variable MAILRC. Reading of this
file can be suppressed with the -: command line option.
mailx-extra-rc
Defines a startup file to be read after all other resource
files. It can be used to specify settings that are not under-
stood by other mailx(1) implementations, for example.
The content of these files is interpreted as follows:
o The whitespace characters space, tabulator and newline, as well as
those defined by the variable ifs, are removed from the beginning and
end of input lines.
o Empty lines are ignored.
o Any other line is interpreted as a command. It may be spread over
multiple input lines if the newline character is "escaped" by placing
a reverse solidus character `\' as the last character of the line;
whereas any leading whitespace of follow lines is ignored, trailing
whitespace before a escaped newline remains in the input.
o If the line (content) starts with the number sign `#' then it is a
comment-command and also ignored. (The comment-command is a real
command, which does nothing, and therefore the usual follow lines
mechanism applies!)
Errors while loading these files are subject to the settings of errexit
and posix. More files with syntactically equal content can be sourceed.
The following, saved in a file, would be an examplary content:
# This line is a comment command. And y\
es, it is really continued here.
set debug \
verbose
set editheaders
The mime.types files
As stated in HTML mail and MIME attachments S-nail needs to learn about
MIME (Multipurpose Internet Mail Extensions) media types in order to
classify message and attachment content. One source for them are
mime.types files, the loading of which can be controlled by setting the
variable mimetypes-load-control. Another is the command mimetype, which
also offers access to S-nails MIME type cache. mime.types files have the
following syntax:
type/subtype extension [extension ...]
# For example text/html html htm
where `type/subtype' define the MIME media type, as standardized in RFC
2046: `type' is used to declare the general type of data, while the
`subtype' specifies a specific format for that type of data. One or mul-
tiple filename `extension's, separated by whitespace, can be bound to the
media type format. Comments may be introduced anywhere on a line with a
number sign `#', causing the remaining line to be discarded. S-nail also
supports an extended, non-portable syntax in especially crafted files,
which can be loaded via the alternative value syntax of
mimetypes-load-control, and prepends an optional `type-marker':
[type-marker ]type/subtype extension [extension ...]
The following type markers are supported:
? Treat message parts with this content as plain text.
?t The same as plain ?.
?h Treat message parts with this content as HTML tagsoup. If the
[Option]al HTML-tagsoup-to-text converter is not available
treat the content as plain text instead.
?H Likewise ?h, but instead of falling back to plain text require
an explicit content handler to be defined.
?q If no handler can be found a text message is displayed which
says so. This can be annoying, for example signatures serve a
contextual purpose, their content is of no use by itself. This
marker will avoid displaying the text message.
Further reading: for sending messages: mimetype,
mime-allow-text-controls, mimetypes-load-control. For reading etc. mes-
sages: HTML mail and MIME attachments, The Mailcap files, mimetype,
mime-counter-evidence, mimetypes-load-control, pipe-TYPE/SUBTYPE,
pipe-EXTENSION.
The Mailcap files
[Option] RFC 1524 defines a "User Agent Configuration Mechanism" to be
used to inform mail user agent programs about the locally installed fa-
cilities for handling various data formats, i.e., about commands and how
they can be used to display, edit et cetera MIME part contents, as well
as a default path search that includes multiple possible locations of re-
source files, and the MAILCAPS environment variable to overwrite that.
Handlers found from doing the path search will be cached, the command
mailcap operates on that cache, and the variable mailcap-disable will
suppress automatic loading, and usage of any mailcap handlers. HTML mail
and MIME attachments gives a general overview of how MIME types are han-
dled.
"Mailcap" files consist of a set of newline separated entries. Comment
lines start with a number sign `#' (in the first column!) and are ig-
nored. Empty lines are ignored. All other lines are interpreted as
mailcap entries. An entry definition may be split over multiple lines by
placing the reverse solidus character `\' last in all but the final line.
The standard does not specify how leading whitespace of successive lines
is to be treated, therefore they are retained.
"Mailcap" entries consist of a number of semicolon `;' separated fields.
The first two fields are mandatory and must occur in the specified order,
the remaining fields are optional and may appear in any order. Leading
and trailing whitespace of field content is ignored (removed). The re-
verse solidus `\' character can be used to escape any following character
including semicolon and itself in the content of the second field, and in
value parts of any optional key/value field.
The first field defines the MIME `TYPE/SUBTYPE' the entry is about to
handle (case-insensitively). If the subtype is specified as an asterisk
`*' the entry is meant to match all subtypes of the named type, e.g.,
`audio/*' would match any audio type. The second field is the view shell
command used to display MIME parts of the given type.
Data consuming shell commands will be fed message (MIME part) data on
standard input unless one or more instances of the (unquoted) string `%s'
are used: these formats will be replaced with a temporary file(name) that
has been prefilled with the parts data. Data producing shell commands
are expected to generata data on their standard output unless that format
is used. In all cases any given `%s' format is replaced with a properly
shell quoted filename. When a command requests a temporary file via `%s'
then that will be removed again, as if the x-mailx-tmpfile and
x-mailx-tmpfile-fill flags had been set; unless the command requests
x-mailx-async the x-mailx-tmpfile-unlink flag is also implied; see below
for more.
Optional fields define single-word flags (case-insensitive), or key /
value pairs consisting of a case-insensitive keyword, an equals sign `=',
and a shell command; whitespace surrounding the equals sign is removed.
Optional fields include the following:
compose A program that can be used to compose a new body or body part
in the given format. (Currently unused.)
composetyped
Similar to the compose field, but is to be used when the com-
posing program needs to specify the `Content-type:' header
field to be applied to the composed data. (Currently unused.)
copiousoutput
A flag field which indicates that the output of the view com-
mand is integrable into S-nails normal visual display. It is
mutually exclusive with needsterminal.
description
A textual description that describes this type of data. The
text may optionally be enclosed within double quotation marks
`"'.
edit A program that can be used to edit a body or body part in the
given format. (Currently unused.)
nametemplate
This field specifies a filename format for the `%s' format used
in the shell command fields, in which `%s' will be replaced by
a random string. (The filename is also stored in and passed to
subprocesses via MAILX_FILENAME_TEMPORARY.) The standard says
this is "only expected to be relevant in environments where
filename extensions are meaningful", and so this field is ig-
nored unless the `%s' is a prefix, optionally followed by
(ASCII) alphabetic and numeric characters, the underscore and
the period. For example, to specify that a JPG file is to be
passed to an image viewer with a name ending in `.jpg',
`nametemplate=%s.jpg' can be used.
needsterminal
This flag field indicates that the given shell command must be
run on an interactive terminal. S-nail will temporarily re-
lease the terminal to the given command in interactive mode, in
non-interactive mode this entry will be entirely ignored; this
flag implies x-mailx-noquote.
print A program that can be used to print a message or body part in
the given format. (Currently unused.)
test Specifies a program to be run to test some condition, for exam-
ple, the machine architecture, or the window system in use, to
determine whether or not this mailcap entry applies. If the
test fails, a subsequent mailcap entry should be sought; also
see x-mailx-test-once. Standard I/O of the test program is
redirected from and to /dev/null, and the format `%s' is not
supported (the data does not yet exist).
textualnewlines
A flag field which indicates that this type of data is line-
oriented and that, if encoded in `base64', all newlines should
be converted to canonical form (CRLF) before encoding, and will
be in that form after decoding. (Currently unused.)
x11-bitmap
Names a file, in X11 bitmap (xbm) format, which points to an
appropriate icon to be used to visually denote the presence of
this kind of data. This field is not used by S-nail.
x-mailx-async
Extension flag field that denotes that the given view command
shall be executed asynchronously, without blocking S-nail.
Cannot be used in conjunction with needsterminal; the standard
output of the command will go to /dev/null.
x-mailx-noquote
An extension flag field that indicates that even a
copiousoutput view command shall not be used when quoteing mes-
sages, as it would by default.
x-mailx-test-once
Extension flag which denotes whether the given test command
shall be evaluated once only with its exit status being cached.
This is handy if some global unchanging condition is to be
queried, like "running under the X Window System".
x-mailx-tmpfile
Extension flag field that requests creation of a zero-sized
temporary file, the name of which is to be placed in the envi-
ronment variable MAILX_FILENAME_TEMPORARY. It is an error to
use this flag with commands that include a `%s' format (because
that is implemented by means of this temporary file).
x-mailx-tmpfile-fill
Normally the MIME part content is passed to the handler via
standard input; if this flag is set then the data will instead
be written into the implied x-mailx-tmpfile. In order to cause
deletion of the temporary file you will have to set
x-mailx-tmpfile-unlink explicitly! It is an error to use this
flag with commands that include a `%s' format.
x-mailx-tmpfile-unlink
Extension flag field that requests that the temporary file
shall be deleted automatically when the command loop is entered
again at latest. It is an error to use this flag with commands
that include a `%s' format, or in conjunction with
x-mailx-async. x-mailx-tmpfile is implied.
x-mailx-last-resort
An extension flag that indicates that this handler shall only
be used as a last resort, when no other source (see HTML mail
and MIME attachments) provides a MIME handler.
x-mailx-ignore
An extension that enforces that this handler is not used at
all.
The standard includes the possibility to define any number of additional
fields, prefixed by `x-'. Flag fields apply to the entire "Mailcap" en-
try -- in some unusual cases, this may not be desirable, but differentia-
tion can be accomplished via separate entries, taking advantage of the
fact that subsequent entries are searched if an earlier one does not pro-
vide enough information. For example, if a view command needs to specify
the needsterminal flag, but the compose command shall not, the following
will help out the latter:
application/postscript; ps-to-terminal %s; needsterminal
application/postscript; ps-to-terminal %s; compose=idraw %s
In value parts of command fields any occurrence of the format string `%t'
will be replaced by the `TYPE/SUBTYPE' specification. Any named parame-
ter from a messages' `Content-type:' field may be embedded into the com-
mand line using the format `%{' followed by the parameter name and a
closing brace `}' character. The entire parameter should appear as a
single command line argument, regardless of embedded spaces, shell quot-
ing will be performed by the RFC 1524 processor, thus:
# Message
Content-type: multipart/mixed; boundary=42
# Mailcap file
multipart/*; /usr/local/bin/showmulti \
%t %{boundary} ; composetyped = /usr/local/bin/makemulti
# Executed shell command
/usr/local/bin/showmulti multipart/mixed 42
Note that S-nail does not support handlers for multipart MIME parts as
shown in this example (as of today). It does not support the additional
formats `%n' and `%F'. An example file, also showing how to properly
deal with the expansion of `%s', which includes any quotes that are nec-
essary to make it a valid shell argument by itself and thus will cause
undesired behaviour when placed in additional user-provided quotes:
# Comment line
text/richtext; richtext %s; copiousoutput
text/x-perl; perl -cWT %s; nametemplate = %s.pl
# Exit EX_TEMPFAIL=75 on signal
application/pdf; \
infile=%s\; \
trap "rm -f ${infile}" EXIT\; \
trap "exit 75" INT QUIT TERM\; \
mupdf "${infile}"; \
test = [ -n "${DISPLAY}" ]; \
nametemplate = %s.pdf; x-mailx-async
application/pdf; pdftotext -layout - -; copiousoutput
application/*; echo "This is \\"%t\\" but \
is 50 \% Greek to me" \; < %s head -c 512 | cat -vet; \
copiousoutput; x-mailx-noquote; x-mailx-last-resort
Further reading: HTML mail and MIME attachments, The mime.types files,
mimetype, MAILCAPS, mime-counter-evidence, pipe-TYPE/SUBTYPE,
pipe-EXTENSION.
The .netrc file
User credentials for machine accounts (see On URL syntax and credential
lookup) can be placed in the .netrc file, which will be loaded and cached
when requested by netrc-lookup. The default location ~/.netrc may be
overridden by the NETRC environment variable. As long as syntax con-
straints are honoured the file source may be replaced with the output of
the shell command set in netrc-pipe, to load an encrypted file, for exam-
ple. The cache can be managed with the command netrc.
The file consists of space, tabulator or newline separated tokens. This
parser implements a superset of the original BSD syntax, but users should
nonetheless be aware of portability glitches, shall their .netrc be us-
able across multiple programs and platforms:
o BSD only supports double quotation marks, for example `password "pass
with spaces"'.
o BSD (only?) supports escaping of single characters via a reverse
solidus (a space could be escaped via `\ '), in- as well as outside
of a quoted string. This method is assumed to be present, and will
actively be used to quote double quotation marks `"' and reverse
solidus `\' characters inside the login and password tokens, for ex-
ample for display purposes.
o BSD does not require a final quotation mark of the last user input
token.
o The original BSD (Berknet) parser also supported a format which al-
lowed tokens to be separated with commas - whereas at least Hewlett-
Packard still seems to support this syntax, this parser does not!
o As a non-portable extension some widely-used programs support shell-
style comments: if an input line starts, after any amount of white-
space, with a number sign `#', then the rest of the line is ignored.
o Whereas other programs may require that the .netrc file is accessible
by only the user if it contains a password token for any other login
than "anonymous", this parser will always require these strict per-
missions.
Of the following list of supported tokens this parser uses (and caches)
machine, login and password. An existing default entry will not be used.
machine name
The hostname of the entries' machine, lowercase-normalized be-
fore use. Any further file content, until either end-of-file
or the occurrence of another machine or a default first-class
token is bound (only related) to the machine name.
As an extension that should not be the cause of any worries
this parser supports a single wildcard prefix for name:
machine *.example.com login USER password PASS
machine pop3.example.com login USER password PASS
machine smtp.example.com login USER password PASS
which would match `xy.example.com' as well as
`pop3.example.com', but neither `example.com' nor
`local.smtp.example.com'. In the example neither
`pop3.example.com' nor `smtp.example.com' will be matched by
the wildcard, since the exact matches take precedence (it is
however faster to specify it the other way around).
default This is the same as machine except that it is a fallback entry
that is used shall none of the specified machines match; only
one default token may be specified, and it must be the last
first-class token.
login name
The user name on the remote machine.
password string
The user's password on the remote machine.
account string
Supply an additional account password. This is merely for FTP
purposes.
macdef name
Define a macro. A macro is defined with the specified name; it
is formed from all lines beginning with the next line and con-
tinuing until a blank line is (consecutive newline characters
are) encountered. (Note that macdef entries cannot be utilized
by multiple machines, too, but must be defined following the
machine they are intended to be used with.) If a macro named
init exists, it is automatically run as the last step of the
login process. This is merely for FTP purposes.
EXAMPLES
An example configuration
# This example assumes v15.0 compatibility mode
set v15-compat
# Request strict TLL transport layer security checks
set tls-verify=strict
# Where are the up-to-date TLS certificates?
# (Since we manage up-to-date ones explicitly, do not use any,
# possibly outdated, default certificates shipped with OpenSSL)
#set tls-ca-dir=/etc/ssl/certs
set tls-ca-file=/etc/ssl/certs/ca-certificates.crt
set tls-ca-no-defaults
#set tls-ca-flags=partial-chain
wysh set smime-ca-file="${tls-ca-file}" \
smime-ca-no-defaults #smime-ca-flags="${tls-ca-flags}"
# This could be outsourced to a central configuration file via
# tls-config-file plus tls-config-module if the used library allows.
# CipherString: explicitly define the list of ciphers, which may
# improve security, especially with protocols older than TLS v1.2.
# See ciphers(1). Possibly best to only use tls-config-pairs-HOST
# (or -USER@HOST), as necessary, again..
# Note that TLSv1.3 uses Ciphersuites= instead, which will join
# with CipherString (if protocols older than v1.3 are allowed)
# Curves: especially with TLSv1.3 curves selection may be desired.
# MinProtocol,MaxProtocol: do not use protocols older than TLS v1.2.
# Change this only when the remote server does not support it:
# maybe use chain support via tls-config-pairs-HOST / -USER@HOST
# to define such explicit exceptions, then, e.g.,
# MinProtocol=TLSv1.1
if "$tls-features" =% ,+ctx-set-maxmin-proto,
wysh set tls-config-pairs='\
CipherString=TLSv1.2:!aNULL:!eNULL:@STRENGTH,\
Curves=P-521:P-384:P-256,\
MinProtocol=TLSv1.1'
else
wysh set tls-config-pairs='\
CipherString=TLSv1.2:!aNULL:!eNULL:@STRENGTH,\
Curves=P-521:P-384:P-256,\
Protocol=-ALL\,+TLSv1.1 \, +TLSv1.2\, +TLSv1.3'
endif
# Essential setting: select allowed character sets
set sendcharsets=utf-8,iso-8859-1
# A very kind option: when replying to a message, first try to
# use the same encoding that the original poster used herself!
set reply-in-same-charset
# When replying, do not merge From: and To: of the original message
# into To:. Instead old From: -> new To:, old To: -> merge Cc:.
set recipients-in-cc
# When sending messages, wait until the Mail-Transfer-Agent finishs.
# Only like this you will be able to see errors reported through the
# exit status of the MTA (including the built-in SMTP one)!
set sendwait
# Only use built-in MIME types, no mime.types(5) files
set mimetypes-load-control
# Default directory where we act in (relative to $HOME)
set folder=mail
# A leading "+" (often) means: under *folder*
# *record* is used to save copies of sent messages
set MBOX=+mbox.mbox DEAD=+dead.txt \
record=+sent.mbox record-files record-resent
# Make "file mymbox" and "file myrec" go to..
shortcut mymbox %:+mbox.mbox myrec +sent.mbox
# Not really optional, e.g., for S/MIME
set from='Your Name <address@exam.ple>'
# It may be necessary to set hostname and/or smtp-hostname
# if the "SERVER" of mta and "domain" of from do not match.
# The `urlencode' command can be used to encode USER and PASS
set mta=(smtps?|submissions?)://[USER[:PASS]@]SERVER[:PORT] \
smtp-auth=login/plain... \
smtp-use-starttls
# Never refuse to start into interactive mode, and more
set emptystart \
colour-pager crt= \
followup-to followup-to-honour=ask-yes fullnames \
history-file=+.s-nailhist history-size=-1 history-gabby \
mime-counter-evidence=0b1111 \
prompt='?\$?!\$!/\$^ERRNAME[\$account#\$mailbox-display]? ' \
reply-to-honour=ask-yes \
umask=
# Only include the selected header fields when typing messages
headerpick type retain from_ date from to cc subject \
message-id mail-followup-to reply-to
# ...when forwarding messages
headerpick forward retain subject date from to cc
# ...when saving message, etc.
#headerpick save ignore ^Original-.*$ ^X-.*$
# Some mailing lists
mlist '@xyz-editor\.xyz$' '@xyzf\.xyz$'
mlsubscribe '^xfans@xfans\.xyz$'
# Handle a few file extensions (to store MBOX databases)
filetype bz2 'bzip2 -dc' 'bzip2 -zc' \
gz 'gzip -dc' 'gzip -c' xz 'xz -dc' 'xz -zc' \
zst 'zstd -dc' 'zstd -19 -zc' \
zst.pgp 'gpg -d | zstd -dc' 'zstd -19 -zc | gpg -e'
# A real life example of a very huge free mail provider
# Instead of directly placing content inside `account',
# we `define' a macro: like that we can switch "accounts"
# from within *on-compose-splice*, for example!
define XooglX {
set folder=~/spool/XooglX inbox=+syste.mbox sent=+sent
set from='Your Name <address@examp.ple>'
set pop3-no-apop-pop.gmXil.com
shortcut pop %:pop3s://pop.gmXil.com
shortcut imap %:imaps://imap.gmXil.com
# Or, entirely IMAP based setup
#set folder=imaps://imap.gmail.com record="+[Gmail]/Sent Mail" \
# imap-cache=~/spool/cache
set mta=smtp://USER:PASS@smtp.gmXil.com smtp-use-starttls
# Alternatively:
set mta=smtps://USER:PASS@smtp.gmail.com:465
}
account XooglX {
\call XooglX
}
# Here is a pretty large one which does not allow sending mails
# if there is a domain name mismatch on the SMTP protocol level,
# which would bite us if the value of from does not match, e.g.,
# for people who have a sXXXXeforge project and want to speak
# with the mailing list under their project account (in from),
# still sending the message through their normal mail provider
define XandeX {
set folder=~/spool/XandeX inbox=+syste.mbox sent=+sent
set from='Your Name <address@exam.ple>'
shortcut pop %:pop3s://pop.yaXXex.com
shortcut imap %:imaps://imap.yaXXex.com
set mta=smtps://USER:PASS@smtp.yaXXex.com:465 \
hostname=yaXXex.com smtp-hostname=
}
account XandeX {
\call Xandex
}
# Create some new commands so that, e.g., `ls /tmp' will..
commandalias lls '!ls ${LS_COLOUR_FLAG} -aFlrS'
commandalias llS '!ls ${LS_COLOUR_FLAG} -aFlS'
set pipe-message/external-body='?* echo $MAILX_EXTERNAL_BODY_URL'
# We do not support gpg(1) directly yet. But simple --clearsign'd
# message parts can be dealt with as follows:
define V {
localopts yes
wysh set pipe-text/plain=$'?*#++=?\
< "${MAILX_FILENAME_TEMPORARY}" awk \
-v TMPFILE="${MAILX_FILENAME_TEMPORARY}" \'\
BEGIN{done=0}\
/^-----BEGIN PGP SIGNED MESSAGE-----/,/^$/ {\
if(done++ != 0)\
next;\
print "--- GPG --verify ---";\
system("gpg --verify " TMPFILE " 2>&1");\
print "--- GPG --verify ---";\
print "";\
next;\
}\
/^-----BEGIN PGP SIGNATURE-----/,\
/^-----END PGP SIGNATURE-----/{\
next;\
}\
{print}\
\''
print
}
commandalias V '\'call V
When storing passwords in ~/.mailrc appropriate permissions should be set
on this file with `$ chmod 0600 ~/.mailrc'. If the [Option]al
netrc-lookup is available user credentials can be stored in the central
~/.netrc file instead; e.g., here is a different version of the example
account that sets up SMTP and POP3:
define XandeX {
set folder=~/spool/XandeX inbox=+syste.mbox sent=+sent
set from='Your Name <address@exam.ple>'
set netrc-lookup
# Load an encrypted ~/.netrc by uncommenting the next line
#set netrc-pipe='gpg -qd ~/.netrc.pgp'
set mta=smtps://smtp.yXXXXx.ru:465 \
smtp-hostname= hostname=yXXXXx.com
set pop3-keepalive=240 pop3-no-apop-pop.yXXXXx.ru
commandalias xp fi pop3s://pop.yXXXXx.ru
}
account XandeX {
\call XandeX
}
and, in the ~/.netrc file:
machine *.yXXXXx.ru login USER password PASS
This configuration should now work just fine:
$ echo text | s-nail -dvv -AXandeX -s Subject user@exam.ple
S/MIME step by step
[Option] The first thing that is needed for Signed and encrypted messages
with S/MIME is a personal certificate, and a private key. The certifi-
cate contains public information, in particular a name and email ad-
dress(es), and the public key that can be used by others to encrypt mes-
sages for the certificate holder (the owner of the private key), and to
verify signed messages generated with that certificate('s private key).
Whereas the certificate is included in each signed message, the private
key must be kept secret. It is used to decrypt messages that were previ-
ously encrypted with the public key, and to sign messages.
For personal use it is recommended to get a S/MIME certificate from one
of the major CAs on the Internet. Many CAs offer such certificates for
free. Usually offered is a combined certificate and private key in
PKCS#12 format which S-nail does not accept directly. To convert it to
PEM format, the following shell command can be used; please read on for
how to use these PEM files.
$ openssl pkcs12 -in cert.p12 -out certpem.pem -clcerts -nodes
$ # Alternatively
$ openssl pkcs12 -in cert.p12 -out cert.pem -clcerts -nokeys
$ openssl pkcs12 -in cert.p12 -out key.pem -nocerts -nodes
There is also https://www.CAcert.org which issues client and server cer-
tificates to members of their community for free; their root certificate
(https://www.cacert.org/certs/root.crt) is often not in the default set
of trusted CA root certificates, though, which means their root certifi-
cate has to be downloaded separately, and needs to be part of the S/MIME
certificate validation chain by including it in smime-ca-dir or as a
vivid member of the smime-ca-file. But let us take a step-by-step tour
on how to setup S/MIME with a certificate from CAcert.org despite this
situation!
First of all you will have to become a member of the CAcert.org commu-
nity, simply by registrating yourself via the web interface. Once you
are, create and verify all email addresses you want to be able to create
signed and encrypted messages for/with using the corresponding entries of
the web interface. Now ready to create S/MIME certificates, so let us
create a new "client certificate", ensure to include all email addresses
that should be covered by the certificate in the following web form, and
also to use your name as the "common name".
Create a private key and a certificate request on your local computer
(please see the manual pages of the used commands for more in-depth
knowledge on what the used arguments etc. do):
$ openssl req -nodes -newkey rsa:4096 -keyout key.pem -out creq.pem
Afterwards copy-and-paste the content of "creq.pem" into the certificate-
request (CSR) field of the web form on the CAcert.org website (you may
need to unfold some "advanced options" to see the corresponding text
field). This last step will ensure that your private key (which never
left your box) and the certificate belong together (through the public
key that will find its way into the certificate via the certificate-re-
quest). You are now ready and can create your CAcert certified certifi-
cate. Download and store or copy-and-paste it as "pub.crt".
Yay. In order to use your new S/MIME setup a combined private key/public
key (certificate) file has to be created:
$ cat key.pem pub.crt > ME@HERE.com.paired
This is the file S-nail will work with. If you have created your private
key with a passphrase then S-nail will ask you for it whenever a message
is signed or decrypted, unless this operation has been automated as de-
scribed in Signed and encrypted messages with S/MIME. Set the following
variables to henceforth use S/MIME (setting smime-ca-file is of interest
for verification only):
? set smime-ca-file=ALL-TRUSTED-ROOT-CERTS-HERE \
smime-sign-cert=ME@HERE.com.paired \
smime-sign-digest=SHA512 \
smime-sign from=myname@my.host
Using CRLs with S/MIME or TLS
[Option] Certification authorities (CAs) issue certificate revocation
lists (CRLs) on a regular basis. These lists contain the serial numbers
of certificates that have been declared invalid after they have been is-
sued. Such usually happens because the private key for the certificate
has been compromised, because the owner of the certificate has left the
organization that is mentioned in the certificate, etc. To seriously use
S/MIME or TLS verification, an up-to-date CRL is required for each
trusted CA. There is otherwise no method to distinguish between valid
and invalidated certificates. S-nail currently offers no mechanism to
fetch CRLs, nor to access them on the Internet, so they have to be re-
trieved by some external mechanism.
S-nail accepts CRLs in PEM format only; CRLs in DER format must be con-
verted, like, e.g.:
$ openssl crl -inform DER -in crl.der -out crl.pem
To tell S-nail about the CRLs, a directory that contains all CRL files
(and no other files) must be created. The smime-crl-dir or tls-crl-dir
variables, respectively, must then be set to point to that directory.
After that, S-nail requires a CRL to be present for each CA that is used
to verify a certificate.
FAQ
In general it is a good idea to turn on debug (-d) and / or verbose (-v,
twice) if something does not work well. Very often a diagnostic message
can be produced that leads to the problems' solution.
S-nail shortly hangs on startup
This can have two reasons, one is the necessity to wait for a file lock
and cannot be helped, the other being that S-nail calls the function
uname(2) in order to query the nodename of the box (sometimes the real
one is needed instead of the one represented by the internal variable
hostname). One may have varying success by ensuring that the real host-
name and `localhost' have entries in /etc/hosts, or, more generally, that
the name service is properly setup - and does hostname(1) return the ex-
pected value? Does this local hostname have a domain suffix? RFC 6762
standardized the link-local top-level domain `.local', try again after
adding an (additional) entry with this extension.
I cannot login to Google mail (via OAuth)
Since 2014 some free service providers classify programs as "less secure"
unless they use a special authentication method (OAuth 2.0) which was not
standardized for non-HTTP protocol authentication token query until Au-
gust 2015 (RFC 7628).
Different to Kerberos / GSSAPI, which is developed since the mid of the
1980s, where a user can easily create a local authentication ticket for
her- and himself with the locally installed kinit(1) program, that proto-
col has no such local part but instead requires a world-wide-web query to
create or fetch a token; since there is no local cache this query would
have to be performed whenever S-nail is invoked (in interactive sessions
situation may differ).
S-nail does not directly support OAuth. It, however, supports XOAUTH2 /
OAUTHBEARER, see But, how about XOAUTH2 / OAUTHBEARER? If that is not
used it is necessary to declare S-nail a "less secure app" (on the
providers account web page) in order to read and send mail. However, it
also seems possible to take the following steps instead:
1. give the provider the number of a mobile phone,
2. enable "2-Step Verification",
3. create an application specific password (16 characters), and
4. use that special password instead of the real Google account pass-
word in S-nail (for more on that see the section On URL syntax and
credential lookup).
But, how about XOAUTH2 / OAUTHBEARER?
Following up I cannot login to Google mail (via OAuth) one OAuth-based
authentication method is available: the OAuth 2.0 bearer token usage as
standardized in RFC 6750 (according SASL mechanism in RFC 7628), also
known as XOAUTH2 and OAUTHBEARER, allows fetching a temporary access to-
ken via the web that can locally be used as a password. The protocol is
simple and extendable, token updates or even password changes via a sim-
ple TLS secured server login would be possible in theory, but today a web
browser and an external support tool are prerequisites for using this au-
thentication method. The token times out and must be periodically re-
freshed via the web.
Some hurdles must be taken before being able to use this method. Using
GMail as an example, an application (that is a name) must be registered,
for which credentials, a "client ID" and a "client secret", need to be
created and saved locally (in a secure way). These initial configuration
steps can be performed at
https://console.developers.google.com/apis/credentials Thereafter a re-
fresh token can be requested; a python program to do this for GMail ac-
counts is https://github.com/google/gmail-oauth2-tools/raw/master/python/
oauth2.py:
$ python oauth2.py --user=EMAIL \
--client-id=THE-ID --client-secret=THE-SECRET \
--generate_oauth2_token
To authorize token, visit this url and follow the directions:
https://accounts.google.com/o/oauth2/auth?client_id=...
Enter verification code: ...
Refresh Token: ...
Access Token: ...
Access Token Expiration Seconds: 3600
$ # Of which the last three are actual token responses.
$ # Thereafter access tokens can regularly be refreshed
$ # via the created refresh token (read on)
The generated refresh token must also be saved locally (securely). The
procedure as a whole can be read at https://github.com/google/gmail-
oauth2-tools/wiki/OAuth2DotPyRunThrough Since periodic timers are not yet
supported, keeping an access token up-to-date (from within S-nail) can
only be performed via the hook on-main-loop-tick, or (for sending only)
on-compose-enter (for more on authentication please see the section On
URL syntax and credential lookup):
set on-main-loop-tick=o-m-l-t on-compose-enter=o-c-e
define o-m-l-t {
xcall update_access_token
}
define o-c-e {
xcall update_access_token
}
set access_token_=0
define update_access_token {
local set i epoch_sec epoch_nsec
vput vexpr i epoch
eval set $i # set epoch_sec/_nsec of vexpr epoch
vput vexpr i + $access_token_ 2100
if $epoch_sec -ge $i
vput ! password python oauth2.py --user=EMAIL \
--client-id=THE-ID --client-secret=THE-SECRET \
--refresh-token=THE-REFRESH-TOKEN |\
sed '1b PASS;d; :PASS s/^.\{1,\}:\(.\{1,\}\)$/\1/'
vput csop password trim "$password"
if -n "$verbose"
echo password is <$password>
endif
set access_token_=$epoch_sec
endif
}
Not "defunctional", but the editor key does not work
Two thinkable situations: the first is a shadowed sequence; setting
debug, or the most possible verbose mode, causes a printout of the bind
tree after that is built; being a cache, this happens only upon startup
or after modifying bindings.
Or second, terminal libraries (see On terminal control and line editor,
bind, termcap) may report different codes than the terminal really sends,
rendering bindings dysfunctional because expected and received data do
not match; the verbose listing of bindings will show the byte sequences
that are expected. (One common source of problems is that the -- possi-
bly even non-existing -- keypad is not turned on, and the resulting lay-
out reports the keypad control codes for the normal keyboard keys.)
To overcome the situation use for example the program cat(1) with its op-
tion -v, if available, to see the byte sequences which are actually pro-
duced by keypresses, and use the variable termcap to make S-nail aware of
them. The terminal this is typed on produces some unexpected sequences,
here for an example the shifted home key:
? set verbose
? bind*
# 1B 5B=[ 31=1 3B=; 32=2 48=H
bind base :kHOM z0
? x
$ cat -v
^[[H
$ s-nail -v -Stermcap='kHOM=\E[H'
? bind*
# 1B 5B=[ 48=H
bind base :kHOM z0
Can S-nail git-send-email?
Yes. Put (at least parts of) the following in your ~/.gitconfig:
[sendemail]
smtpserver = /usr/bin/s-nail
smtpserveroption = -t
#smtpserveroption = -Sexpandaddr
smtpserveroption = -Athe-account-you-need
##
suppresscc = all
suppressfrom = false
assume8bitEncoding = UTF-8
#to = /tmp/OUT
confirm = always
chainreplyto = true
multiedit = false
thread = true
quiet = true
annotate = true
Patches can also be send directly, for example:
$ git format-patch -M --stdout HEAD^ |
s-nail -A the-account-you-need -t RECEIVER
Howto handle stale dotlock files
folder sometimes fails to open MBOX mail databases because creation of
dotlock files is impossible due to existing but unowned lock files.
S-nail does not offer an option to deal with those files, because it is
considered a site policy what counts as unowned, and what not. The site
policy is usually defined by administrator(s), and expressed in the con-
figuration of a locally installed MTA (for example Postfix
`stale_lock_time=500s'). Therefore the suggestion:
$ </dev/null s-nail -s 'MTA: be no frog, handle lock' $LOGNAME
By sending a mail to yourself the local MTA can use its normal queue
mechanism to try the delivery multiple times, finally decide a lock file
has become stale, and remove it.
IMAP CLIENT
[Option]ally there is IMAP client support available. This part of the
program is obsolete and will vanish in v15 with the large MIME and I/O
layer rewrite, because it uses old-style blocking I/O and makes excessive
use of signal based long code jumps. Support can hopefully be readded
later based on a new-style I/O, with SysV signal handling. In fact the
IMAP support had already been removed from the codebase, but was rein-
stantiated on user demand: in effect the IMAP code is at the level of
S-nail v14.8.16 (with imapcodec being the sole exception), and should be
treated with some care.
IMAP uses the `imap://' and `imaps://' protocol prefixes, and an IMAP-
based folder may be used. IMAP URLs (paths) undergo inspections and pos-
sible transformations before use (and the command imapcodec can be used
to manually apply them to any given argument). Hierarchy delimiters are
normalized, a step which is configurable via the imap-delim variable
chain, but defaults to the first seen delimiter otherwise. S-nail sup-
ports internationalised IMAP names, and en- and decodes the names from
and to the ttycharset as necessary and possible. If a mailbox name is
expanded (see Filename transformations) to an IMAP mailbox, all names
that begin with `+' then refer to IMAP mailboxes below the folder target
box, while folder names prefixed by `@' refer to folders below the hier-
archy base, so the following will list all folders below the current one
when in an IMAP mailbox: `folders @'.
Note: some IMAP servers do not accept the creation of mailboxes in the
hierarchy base, but require that they are created as subfolders of `IN-
BOX' - with such servers a folder name of the form
imaps://mylogin@imap.myisp.example/INBOX.
should be used (the last character is the server's hierarchy delimiter).
The following IMAP-specific commands exist:
cache Only applicable to cached IMAP mailboxes; takes a message list
and reads the specified messages into the IMAP cache.
connect If operating in disconnected mode on an IMAP mailbox, switch to
online mode and connect to the mail server while retaining the
mailbox status. See the description of the disconnected vari-
able for more information.
disconnect
If operating in online mode on an IMAP mailbox, switch to dis-
connected mode while retaining the mailbox status. See the de-
scription of the disconnected variable for more. A list of
messages may optionally be given as argument; the respective
messages are then read into the cache before the connection is
closed, thus `disco *' makes the entire mailbox available for
disconnected use.
imap Sends command strings directly to the current IMAP server.
S-nail operates always in IMAP `selected state' on the current
mailbox; commands that change this will produce undesirable re-
sults and should be avoided. Useful IMAP commands are:
create Takes the name of an IMAP mailbox as an
argument and creates it.
getquotaroot (RFC 2087) Takes the name of an IMAP mail-
box as an argument and prints the quotas
that apply to the mailbox. Not all IMAP
servers support this command.
namespace (RFC 2342) Takes no arguments and prints
the Personal Namespaces, the Other User's
Namespaces and the Shared Namespaces.
Each namespace type is printed in paren-
theses; if there are multiple namespaces
of the same type, inner parentheses sepa-
rate them. For each namespace a prefix
and a hierarchy separator is listed. Not
all IMAP servers support this command.
imapcodec
Perform IMAP path transformations. Supports vput (see Command
modifiers), and manages the error number !. The first argument
specifies the operation: e[ncode] normalizes hierarchy delim-
iters (see imap-delim) and converts the strings from the locale
ttycharset to the internationalized variant used by IMAP,
d[ecode] performs the reverse operation. Encoding will honour
the (global) value of imap-delim.
The following IMAP-specific internal variables exist:
disconnected
(Boolean) When an IMAP mailbox is selected and this variable is
set, no connection to the server is initiated. Instead, data
is obtained from the local cache (see imap-cache). Mailboxes
that are not present in the cache and messages that have not
yet entirely been fetched from the server are not available; to
fetch all messages in a mailbox at once, the command `copy *
/dev/null' can be used while still in connected mode. Changes
that are made to IMAP mailboxes in disconnected mode are queued
and committed later when a connection to that server is made.
This procedure is not completely reliable since it cannot be
guaranteed that the IMAP unique identifiers (UIDs) on the
server still match the ones in the cache at that time. Data is
saved to DEAD when this problem occurs.
disconnected-USER@HOST
The specified account is handled as described for the
disconnected variable above, but other accounts are not af-
fected.
imap-auth-USER@HOST, imap-auth
Sets the IMAP authentication method. Supported are the default
`login', [v15-compat] `oauthbearer' (see FAQ entry But, how
about XOAUTH2 / OAUTHBEARER?), [v15-compat] `external' and
`externanon' (for TLS secured connections which pass a client
certificate via tls-config-pairs), as well as the [Option]al
`cram-md5' and `gssapi'. All methods need a user and a
password except `gssapi' and `external', which only need the
former. `externanon' solely builds upon the credentials passed
via a client certificate, and is usually the way to go since
tested servers do not actually follow RFC 4422, and fail if ad-
ditional credentials are actually passed.
imap-cache
Enables caching of IMAP mailboxes. The value of this variable
must point to a directory that is either existent or can be
created by S-nail. All contents of the cache can be deleted by
S-nail at any time; it is not safe to make assumptions about
them.
imap-delim-USER@HOST, imap-delim-HOST, imap-delim
The hierarchy separator used by the IMAP server. Whenever an
IMAP path is specified it will undergo normalization. One of
the normalization steps is the squeezing and adjustment of hi-
erarchy separators. If this variable is set, any occurrence of
any character of the given value that exists in the path will
be replaced by the first member of the value; an empty value
will cause the default to be used, it is `/.'. If not set, we
will reuse the first hierarchy separator character that is dis-
covered in a user-given mailbox name.
imap-keepalive-USER@HOST, imap-keepalive-HOST, imap-keepalive
IMAP servers may close the connection after a period of inac-
tivity; the standard requires this to be at least 30 minutes,
but practical experience may vary. Setting this variable to a
numeric `value' greater than 0 causes a `NOOP' command to be
sent each `value' seconds if no other operation is performed.
imap-list-depth
When retrieving the list of folders on an IMAP server, the
folders command stops after it has reached a certain depth to
avoid possible infinite loops. The value of this variable sets
the maximum depth allowed. The default is 2. If the folder
separator on the current IMAP server is a slash `/', this vari-
able has no effect and the folders command does not descend to
subfolders.
imap-use-starttls-USER@HOST, imap-use-starttls-HOST, imap-use-starttls
Causes S-nail to issue a `STARTTLS' command to make an unen-
crypted IMAP session TLS encrypted. This functionality is not
supported by all servers, and is not used if the session is al-
ready encrypted by the IMAPS method.
SEE ALSO
bogofilter(1), gpg(1), more(1), newaliases(1), openssl(1), sendmail(1),
sh(1), spamassassin(1), iconv(3), setlocale(3), aliases(5), termcap(5),
terminfo(5), locale(7), mailaddr(7), re_format(7) (or regex(7)),
mailwrapper(8), sendmail(8)
HISTORY
M. Douglas McIlroy writes in his article "A Research UNIX Reader:
Annotated Excerpts from the Programmer's Manual, 1971-1986" that a
mail(1) command already appeared in First Edition UNIX in 1971:
Electronic mail was there from the start. Never satisfied with its
exact behavior, everybody touched it at one time or another: to as-
sure the safety of simultaneous access, to improve privacy, to sur-
vive crashes, to exploit uucp, to screen out foreign freeloaders,
or whatever. Not until v7 did the interface change (Thompson).
Later, as mail became global in its reach, Dave Presotto took
charge and brought order to communications with a grab-bag of ex-
ternal networks (v8).
BSD Mail, in large parts compatible with UNIX mail, was written in 1978
by Kurt Shoens and developed as part of the BSD UNIX distribution until
1995. This manual page is derived from "The Mail Reference Manual" that
Kurt Shoens wrote for Mail 1.3, included in 3BSD in 1980. The common
UNIX and BSD denominator became standardized as mailx(1) in the X/Open
Portability Guide Issue 2 (January 1987). After the rise of Open Source
BSD variants Mail saw continuous development in the individual code
forks, noticeably by Christos Zoulas in NetBSD. Based upon this Nail,
later Heirloom Mailx, was developed by Gunnar Ritter in the years 2000
until 2008. Since 2012 S-nail is maintained by Steffen Nurpmeso.
Electronic mail exchange in general is a concept even older. The earli-
est well documented electronic mail system was part of the Compatible
Time Sharing System (CTSS) at MIT, its MAIL command had been proposed in
a staff planning memo at the end of 1964 and was implemented in mid-1965
when Tom Van Vleck and Noel Morris wrote the necessary code. Similar
communication programs were built for other timesharing systems. One of
the most ambitious and influential was Murray Turoff's EMISARI. Created
in 1971 for the United States Office of Emergency Preparedness, EMISARI
combined private electronic messages with a chat system, public postings,
voting, and a user directory.
During the 1960s it was common to connect a large number of terminals to
a single, central computer. Connecting two computers together was rela-
tively unusual. This began to change with the development of the
ARPANET, the ancestor of today's Internet. In 1971 Ray Tomlinson adapted
the SNDMSG program, originally developed for the University of California
at Berkeley timesharing system, to give it the ability to transmit a mes-
sage across the network into the mailbox of a user on a different com-
puter. For the first time it was necessary to specify the recipient's
computer as well as an account name. Tomlinson decided that the under-
used commercial at `@' would work to separate the two.
Sending a message across the network was originally treated as a special
instance of transmitting a file, and so a MAIL command was included in
RFC 385 on file transfer in 1972. Because it was not always clear when
or where a message had come from, RFC 561 in 1973 aimed to formalize
electronic mail headers, including "from", "date", and "subject". In
1975 RFC 680 described fields to help with the transmission of messages
to multiple users, including "to", "cc", and "bcc". In 1977 these fea-
tures and others went from best practices to a binding standard in RFC
733. Queen Elizabeth II of England became the first head of state to
send electronic mail on March 26 1976 while ceremonially opening a build-
ing in the British Royal Signals and Radar Establishment (RSRE) in
Malvern.
AUTHORS
Kurt Shoens, Edward Wang, Keith Bostic, Christos Zoulas, Gunnar Ritter.
S-nail is developed by Steffen Nurpmeso <s-mailx@lists.sdaoden.eu>.
CAVEATS
[v15 behaviour may differ] Interrupting an operation via SIGINT aka
`control-C' from anywhere else but a command prompt is very problematic
and likely to leave the program in an undefined state: many library func-
tions cannot deal with the siglongjmp(3) that this software (still) per-
forms; even though efforts have been taken to address this, no sooner but
in v15 it will have been worked out: interruptions have not been disabled
in order to allow forceful breakage of hanging network connections, for
example (all this is unrelated to ignore).
The SMTP and POP3 protocol support of S-nail is very basic. Also, if it
fails to contact its upstream SMTP server, it will not make further at-
tempts to transfer the message at a later time (setting save and sendwait
may be useful). If this is a concern, it might be better to set up a lo-
cal SMTP server that is capable of message queuing.
BUGS
When a network-based mailbox is open, directly changing to another net-
work-based mailbox of a different protocol (i.e., from POP3 to IMAP or
vice versa) will cause a "deadlock".
After deleting some message of a POP3 mailbox the header summary falsely
claims that there are no messages to display, one needs to perform a
scroll or dot movement to restore proper state.
In `thread'ed sort mode a power user may encounter crashes very occasion-
ally (this is may and very).
Please report bugs to the contact-mail address, for example from within
s-nail: `? eval mail $contact-mail'. Including the verbose output of the
command version may be helpful:
? wysh set escape=! verbose; vput version xy; unset verbose;\
eval mail $contact-mail
Bug subject
!I xy
!.
Information on the web at `$ s-nail -X 'echo $contact-web; x''.
BSD February 24, 2021 BSD