1 .\"@ nail.1 - S-nail(1) reference manual.
3 .\" Copyright (c) 1980, 1990, 1993
4 .\" The Regents of the University of California. All rights reserved.
6 .\" Gunnar Ritter. All rights reserved.
7 .\" Copyright (c) 2012 - 2015 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
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10 .\" modification, are permitted provided that the following conditions
12 .\" 1. Redistributions of source code must retain the above copyright
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15 .\" notice, this list of conditions and the following disclaimer in the
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19 .\" This product includes software developed by the University of
20 .\" California, Berkeley and its contributors.
21 .\" This product includes software developed by Gunnar Ritter
22 .\" and his contributors.
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37 .\" S-nail(1): v14.8.10 / 2016-08-20
49 .\" If not ~/.mailrc, it breaks POSIX compatibility. And adjust main.c.
54 .ds OU [no v15-compat]
55 .ds ID [v15 behaviour may differ]
56 .ds NQ [Only new quoting rules]
67 .Nd send and receive Internet mail
73 .\" Keep in SYNC: ./nail.1:"SYNOPSIS, main()
81 .Op Fl a Ar attachment
84 .Op Fl M Ar type | Fl m Ar file | Fl q Ar file | Fl t
86 .Op Fl S Ar var Ns Op Ns = Ns Ar value
91 .Op Fl Fl \~ Ns Ar mta-option ...
100 .Op Fl S Ar var Ns Op Ns = Ns Ar value
103 .Op Fl Fl \~ Ns Ar mta-option ...
111 .Op Fl L Ar spec-list
112 .Op Fl r Ar from-addr
113 .Op Fl S Ar var Ns Op Ns = Ns Ar value
116 .Op Fl Fl \~ Ns Ar mta-option ...
121 .Mx -toc -tree html pdf ps xhtml
124 .\" .Sh DESCRIPTION {{{
127 .Bd -filled -compact -offset indent
128 .Sy Compatibility note:
129 S-nail (\*(UA) will wrap up into \%S-mailx in v15.0 (circa 2018).
130 Backward incompatibility has to be expected \(en
134 -style argument quoting rules, for example.
135 New and old behaviour is flagged \*(IN and \*(OU, and setting
138 .Sx "INTERNAL VARIABLES" ,
139 will choose new behaviour when applicable.
140 \*(OB flags what will vanish, and enabling
144 enables obsoletion warnings.
148 \*(UA is a mail processing system with a command syntax reminiscent of
150 with lines replaced by messages.
151 It is intended to provide the functionality of the POSIX
153 command, but is MIME capable and optionally offers extensions for
154 line editing, S/MIME, SMTP and POP3 among others.
155 It is usable as a mail batch language.
157 .\" .Ss "Options" {{{
160 .Bl -tag -width ".Fl _ Ar _ddr"
163 Explicitly control which of the
165 shall be loaded: if the letter
167 is (case-insensitively) part of the
171 is loaded, likewise the letter
173 controls loading of the user's personal
175 file, whereas the letters
179 explicitly forbid loading of any resource files.
180 This option should be used by scripts: to avoid environmental noise they
183 from any configuration files and create a script-local environment,
184 explicitly setting any of the desired
185 .Sx "INTERNAL VARIABLES"
188 This option overrides
195 command for the given user email
197 after program startup is complete.
198 Being a special incarnation of
200 macros for the purpose of bundling longer-lived settings, activating
201 such an email account also switches to the accounts
207 Attach the given file to the message.
208 The same filename conventions as described in the section
210 apply: shell word expansion is restricted to the tilde
214 not be accessible but contain a
216 character, then anything after the
218 is assumed to specify the input character set and anything before
220 the filename: this is the only option to specify the input character set
221 (and don't perform any character set conversion) for text attachments
222 from the command line, not using the
224 tilde escape command.
228 Make standard input and standard output line-buffered.
232 Send a blind carbon copy to
235 May be used multiple times, but it is also possible to give
236 a comma-separated list of receivers in a single argument, proper quoting
238 .Ql -b """qrec1 , rec2,rec3, Ex <am@ple>""" .
240 .Sx "On sending mail, and non-interactive mode" .
244 Send carbon copies to the given receiver(s).
245 May be used multiple times.
251 variable which enables debug messages and disables message delivery,
252 among others; effectively turns almost any operation into a dry-run.
258 variable and thus discard messages with an empty message part body.
259 This is useful for sending messages from scripts.
263 Just check if mail is present (in the specified or system
265 box): if yes, return an exit status of zero, a non-zero value otherwise.
266 To restrict the set of mails to consider in this evaluation a message
267 specification can be added with the option
272 Save the message to send in a file named after the local part of the
273 first recipient's address (instead of in
278 Read in the contents of the user's
280 (or the specified file) for processing;
281 when \*(UA is quit, it writes undeleted messages back to this file
285 Some special conventions are recognized for the optional
287 argument which are documented for the
292 is not a argument to the flag
294 but is instead taken from the command line after option processing has
298 that starts with a hyphen, prefix it with a (relative) path, as in
299 .Ql ./-hyphenbox.mbox .
303 Display a summary of the
305 of all messages in the specified or system
308 A configurable summary view is available via the
314 Show a short usage summary.
315 Because of widespread use a
317 argument will have the same effect.
323 variable to ignore tty interrupt signals.
326 .It Fl L Ar spec-list
327 Display a summary of all
329 of only those messages in the specified or system
331 box that match the given
335 .Sx "Specifying messages"
342 option has been given in addition no header summary is produced,
343 but \*(UA will instead indicate via its exit status whether
349 note that any verbose output is suppressed in this mode and must instead
350 be enabled explicitly (e.g., by using the option
355 Special send mode that will flag standard input with the MIME
359 and use it as the main message body.
360 \*(ID Using this option will bypass processing of
361 .Va message-inject-head ,
364 .Va message-inject-tail .
370 Special send mode that will MIME classify the specified
372 and use it as the main message body.
373 \*(ID Using this option will bypass processing of
374 .Va message-inject-head ,
377 .Va message-inject-tail .
385 variable and thus inhibit initial display of message headers when
386 reading mail or editing a mail folder.
390 Standard flag that inhibits reading the system wide
395 allows more control over the startup sequence; also see
396 .Sx "Resource files" .
400 Special send mode that will initialize the message body with the
401 contents of the specified
403 which may be standard input
405 only in non-interactive context.
411 Any folder opened will be in read-only mode.
414 .It Fl r Ar from-addr
417 is a valid address then it specifies the envelope sender address to be
420 when a message is send.
423 include a user name, then the address components will be separated and
424 the name part will be passed to the MTA individually via
428 will also be assigned to the
431 .Ql -Sfrom=from-addr ) ,
432 therefore affecting possible SMTP data transfer;
433 note this assignment does not cause value fixation.
435 If instead an empty string is passed as
437 then the content of the variable
439 will be evaluated and used for this purpose whenever the MTA is
441 Note that \*(UA by default, without
443 that is, neither passes
447 flags to the MTA by itself.
450 .It Fl S Ar var Ns Op = Ns value
453 iable and, in case of a value variable, assigns
456 Even though variables (see
457 .Sx "INTERNAL VARIABLES" )
461 may be overwritten from within resource files,
462 the command line setting will be reestablished after all resource files
467 Specify the subject of the to-be-sent message.
471 The message given (on standard input) is expected to contain, separated
472 from the message body by an empty line, a message header with
477 fields giving its recipients, which will be added to any recipients
478 specified on the command line.
479 If a message subject is specified via
481 then it'll be used in favour of one given on the command line.
499 .Ql Mail-Followup-To: ,
500 by default created automatically dependent on message context, will
501 be used if specified (a special address massage will however still occur
503 Any other (even custom) header field is passed through entirely
504 unchanged, and in conjunction with the option
506 it is even possible to embed
513 Initially read the primary system mailbox of
515 appropriate privileges presumed; effectively identical to
520 Show \*(UA's version and exit.
526 variable enables display of some informational context messages.
527 Using it twice increases the level of verbosity.
533 to the list of commands to be executed before normal operation starts.
537 .Va batch-exit-on-error ;
538 the only possibility to execute commands in non-interactive mode when
539 reading startup files is actively prohibited.
545 even if not in interactive mode.
546 This can be used to, e.g., automatically format the composed message
547 text before sending the message:
548 .Bd -literal -offset indent
549 $ ( echo 'line one. Word. Word2.'; \e
550 echo '~| /usr/bin/fmt -tuw66' ) |\e
551 LC_ALL=C \*(uA -:/ -d~ bob@exam.ple
557 In batch mode the full set of commands is available, just like in
558 interactive mode, and diverse variable settings and internal states are
559 adjusted for batch necessities, e.g., it sets
572 is enabled in compose mode.
573 The following prepares an email message in a batched dry run:
574 .Bd -literal -offset indent
575 $ LC_ALL=C printf 'm bob\en~s ubject\enText\en~.\enx\en' | \e
576 LC_ALL=C \*(uA -:/ -d# -X'alias bob bob@exam.ple'
581 This flag forces termination of option processing in order to prevent
584 It also forcefully puts \*(UA into send mode, see
585 .Sx "On sending mail, and non-interactive mode" .
589 In the above list of supported command line options,
593 are implemented by means of setting the respective option, as via
596 .Op Ar mta-option ...
598 arguments that are given at the end of the command line after a
600 separator will be passed through to the mail-transfer-agent (MTA) and
601 persist for an entire (interactive) session \(en if the setting of
603 allows their recognition;
604 MTA arguments can also be specified in the variable
605 .Va sendmail-arguments ;
606 find MTA interaction described in more detail in the documentation of
608 MTA arguments are ignored when mail is send via SMTP data transfer.
611 .\" .Ss "A starter" {{{
614 \*(UA is a direct descendant of
616 Mail, a successor of the Research
619 .Dq was there from the start
624 Mail reference manual begins with the following words:
626 .Bd -ragged -offset indent
627 Mail provides a simple and friendly environment for sending and
629 It divides incoming mail into its constituent messages and allows the
630 user to deal with them in any order.
631 In addition, it provides a set of
633 -like commands for manipulating messages and sending mail.
634 Mail offers the user simple editing capabilities to ease the composition
635 of outgoing messages, as well as providing the ability to define and
636 send to names which address groups of users.
640 \*(UA is thus the user side of the
642 mail system, whereas the system side (mail-transfer-agent, MTA) was
643 traditionally taken by
645 and most MTAs provide a binary of this name for compatibility purposes.
646 If the \*(OPal SMTP is included in the
648 of \*(UA then the system side is not a mandatory precondition for mail
652 Because \*(UA strives for compliance with POSIX
654 it is likely that some configuration settings have to be adjusted before
655 using it is a smooth experience.
658 file already bends those standard imposed settings a bit towards more
659 user friendliness and safety, e.g., it sets the
663 variables in order to suppress the automatic moving of messages to
665 that would otherwise occur (see
666 .Sx "Message states" )
669 to not remove empty files in order not to mangle file permissions when
670 files eventually get recreated (\*(UA actively manages the file mode
673 upon program startup).
677 .Sx "INTERNAL VARIABLES" ,
678 isn't set by default so that file grouping (via the
680 prefix as documented for
682 is not functional by default.
685 contains some suggestions.
688 .\" .Ss "On sending mail, and non-interactive mode" {{{
689 .Ss "On sending mail, and non-interactive mode"
691 To send a message to one or more people, using a local
692 mail-transfer-agent (MTA; the executable path can be set via
694 or the \*(OPal builtin SMTP (set and see the variable
696 transport to actually deliver the generated mail message, \*(UA can be
697 invoked with arguments which are the names of people to whom the mail
698 will be sent, and the command line options
702 can be used to add (blind) carbon copy receivers:
704 .Bd -literal -offset indent
705 $ \*(uA -s ubject -a ttach.txt bill@exam.ple
706 # But... try it in an isolated dry-run mode first
707 $ LC_ALL=C \*(uA -:/ -d -vv -Ssendwait \e
708 -b bcc@exam.ple -c cc@exam.ple -s "A subject" -. \e
709 "(Lovely) Bob <bob@exam.ple>" eric@exam.ple
713 If standard input is a terminal rather than the message to be sent,
714 the user is expected to type in the message contents.
715 In this compose mode \*(UA treats lines beginning with the character
717 special \(en these are so-called
719 which can be used to read in files, process shell commands, add and edit
720 attachments and more; e.g., the tilde escape
722 will start the text editor to revise the message in it's current state,
724 allows editing of the most important message headers and
726 gives an overview of available tilde escapes.
730 at the beginning of an empty line leaves compose mode and causes the
731 message to be sent, whereas typing
734 twice will abort the current letter (saving its contents in the file
740 Messages are sent asynchronously unless the variable
742 is set, therefore send errors won't be reported.
748 .Sx "INTERNAL VARIABLES"
749 can be used to alter default behavior; e.g.,
754 will automatically startup a text editor when compose mode is entered,
756 will cause the user to be prompted actively for carbon-copy recipients
759 option will allow leaving compose mode by writing a line consisting
765 hook macros may be set to automatically adjust some settings dependent
766 on receiver, sender or subject contexts.
771 is often necessary (e.g., for
773 transfer), and saving a copy of sent messages in a
775 may be desirable \(en as for most mailbox file targets some special
776 syntax conventions are recognized (see the
778 command for more on that).
781 for the purpose of arranging a complete environment of settings that can
782 be switched to with a single command or command line option may be
785 contains example configurations for sending messages via some of the
786 well-known public mail providers and also gives a compact overview on
787 how to setup a secure SSL/TLS environment).
792 sandbox dry-run tests first will prove correctness.
796 .Sx "On URL syntax and credential lookup"
797 will spread light on the different ways of how to specify user email
798 account credentials, the
800 variable chains, and accessing protocol-specific resources,
803 goes into the details of character encoding and how to use them for
804 representing messages and MIME part contents by specifying them in
806 and reading the section
807 .Sx "The mime.types files"
808 should help to understand how the MIME-type of outgoing attachments are
809 classified, and what can be done for fine-tuning.
812 Message recipients (as specified on the command line or defined in
817 may not only be email addressees but can also be names of mailboxes and
818 even complete shell command pipe specifications.
821 is not set then only network addresses (see
823 for a description of mail addresses) and plain user names (including MTA
824 aliases) may be used, other types will be filtered out, giving a warning
827 .\" When changing any of the following adjust any RECIPIENTADDRSPEC;
828 .\" grep the latter for the complete picture
832 is set then extended recipient addresses will optionally be accepted:
833 Any name which starts with a vertical bar
835 character specifies a command pipe \(en the command string following the
837 is executed and the message is sent to its standard input;
838 Likewise, any name that starts with the character solidus
840 or the character sequence dot solidus
842 is treated as a file, regardless of the remaining content.
843 Any other name which contains an at sign
845 character is treated as a network address;
846 Any other name which starts with a plus sign
848 character specifies a mailbox name;
849 Any other name which contains a solidus
851 character but no exclamation mark
855 character before also specifies a mailbox name;
856 What remains is treated as a network address.
858 .Bd -literal -offset indent
859 $ echo bla | \*(uA -Sexpandaddr -s test ./mbox.mbox
860 $ echo bla | \*(uA -Sexpandaddr -s test '|cat >> ./mbox.mbox'
861 $ echo safe | LC_ALL=C \e
862 \*(uA -:/ -Sv15-compat -Ssendwait -Snosave \e
863 -Sexpandaddr=fail,-all,+addr -s test \e
868 It is possible to create personal distribution lists via the
870 command, so that, for instance, the user can send mail to
872 and have it go to a group of people.
873 These aliases have nothing in common with the system wide aliases that
874 may be used by the MTA (mail-transfer-agent), which are subject to the
878 and are often tracked in a file
884 Personal aliases will be expanded by \*(UA before the message is sent,
885 and are thus a convenient alternative to specifying each addressee by
889 .Dl alias cohorts bill jkf mark kridle@ucbcory ~/mail/cohorts.mbox
892 To avoid environmental noise scripts should
894 \*(UA from any configuration files and create a script-local
895 environment, ideally with the command line options
897 to disable any configuration file in conjunction with repetitions of
899 to specify variables:
901 .Bd -literal -offset indent
903 \*(uA -:/ -Sv15-compat -Ssendwait -Snosave \e
904 -Sexpandaddr=fail,-all,+addr \e
905 -S 'smtp=smtps://mylogin@exam.ple:465' -Ssmtp-auth=login \e
906 -S 'from=scriptreply@exam.ple' \e
907 -s 'subject' -a attachment_file \e
908 -. "Recipient 1 <rec1@exam.ple>" rec2@exam.ple \e
913 In interactive mode, which is introduced in the next section, messages
914 can be sent by calling the
916 command with a list of recipient addresses \(em the semantics are
917 completely identical to non-interactive message sending:
919 .Bd -literal -offset indent
920 $ \*(uA -d -Squiet -Semptystart
921 "/var/spool/mail/user": 0 messages
922 ? mail "Recipient 1 <rec1@exam.ple>", rec2@exam.ple
923 ? # Will do the right thing (tm)
924 ? m rec1@exam.ple rec2@exam.ple
928 .\" .Ss "On reading mail, and interactive mode" {{{
929 .Ss "On reading mail, and interactive mode"
931 When invoked without addressees \*(UA enters interactive mode in which
933 When used like that the user's system
937 for an in-depth description of the different mailbox types that exist)
938 is read in and a one line header of each message therein is displayed.
939 The visual style of this summary of
941 can be adjusted through the variable
943 and the possible sorting criterion via
945 If the initially opened mailbox is empty \*(UA will instead exit
946 immediately (after displaying a message) unless the variable
955 will give a listing of all available commands and
957 will give a summary of some common ones.
958 If the \*(OPal documentation strings are available one can type
960 and see the actual expansion of
962 and what it's purpose is, i.e., commands can be abbreviated
963 (note that POSIX defines some abbreviations, so that the alphabetical
964 order of commands doesn't necessarily relate to the abbreviations; it is
965 possible to define overwrites with the
970 Messages are given numbers (starting at 1) which uniquely identify
971 messages; the current message \(en the
973 \(en will either be the first new message, or the first unread message,
974 or the first message of the mailbox; the option
976 will instead cause usage of the last message for this purpose.
981 ful of header summaries containing the
985 will display only the summaries of the given messages, defaulting to the
989 Messages can be displayed on the user's terminal with the
993 By default the current message
995 is displayed, but like with many other commands it is possible to give
996 a fancy message specification (see
997 .Sx "Specifying messages" ) ,
1000 will display all unread messages,
1005 will type the messages 1 and 5,
1007 will type the messages 1 through 5, and
1011 will display the last and the next message, respectively.
1014 (a more substantial alias of the standard command
1016 will display a header summary of the given message specification list
1017 instead of their content, e.g., the following will search for subjects:
1020 .Dl from """@Some subject to search for"""
1023 In the default setup all header fields of a message will be displayed,
1024 but this can be changed: either by blacklisting a list of fields via
1026 or by whitelisting only a given list with the
1029 .Ql Ic \:retain Ns \0date from to cc subject .
1030 In order to display all header fields of a message regardless of
1031 currently active ignore or retain lists, use the command
1035 controls whether and when \*(UA will use the configured
1037 for display instead of directly writing to the user terminal
1038 (generally speaking).
1039 Note that historically the global
1041 not only adjusts the list of displayed headers, but also sets
1045 Dependent upon the configuration a line editor (see the section
1046 .Sx "On terminal control and line editor" )
1047 aims at making user experience with the many
1050 When reading the system
1056 specified a mailbox explicitly prefixed with the special
1058 modifier (propagating the mailbox to a primary one) then messages which
1059 have been read will be moved to a secondary mailbox, the user's
1061 file, automatically when the mailbox is left, either by changing the
1062 active mailbox or by quitting \*(UA (also see
1063 .Sx "Message states" )
1064 \(en this automatic moving from a system or primary to the secondary
1065 mailbox is not performed when the variable
1070 After examining a message the user can also
1074 to the sender and all recipients or
1076 exclusively to the sender(s).
1077 Messages can also be
1079 ed (shorter alias is
1081 Note that when replying to or forwarding a message recipient addresses
1082 will be stripped from comments and names unless the option
1085 Deletion causes \*(UA to forget about the message;
1086 This is not irreversible, though, one can
1088 the message by giving its number,
1089 or the \*(UA session can be ended by giving the
1094 To end a mail processing session one may either issue
1096 to cause a full program exit, which possibly includes
1097 automatic moving of read messages to
1099 as well as updating the \*(OPal line editor
1103 instead in order to prevent any of these actions.
1106 .\" .Ss "HTML mail and MIME attachments" {{{
1107 .Ss "HTML mail and MIME attachments"
1109 Messages which are HTML-only get more and more common and of course many
1110 messages come bundled with a bouquet of MIME attachments.
1111 Whereas \*(UA \*(OPally supports a simple HTML-to-text converter to deal
1112 with HTML messages (see
1113 .Sx "The mime.types files" ) ,
1114 it normally can't deal with any of these itself, but instead programs
1115 need to become registered to deal with specific MIME types or file
1117 These programs may either prepare plain text versions of their input
1118 in order to enable \*(UA to display the content on the terminal,
1119 or display the content themselves, for example in a graphical window.
1122 To install an external handler program for a specific MIME type set an
1124 .Va pipe-TYPE/SUBTYPE
1125 variable; to instead define a handler for a specific file extension set
1128 variable \(en these handlers take precedence.
1129 \*(OPally \*(UA supports mail user agent configuration as defined in
1130 RFC 1524; this mechanism, documented in the section
1131 .Sx "The Mailcap files" ,
1132 will be queried for display or quote handlers if none of the former two
1133 .\" TODO v15-compat "will be" -> "is"
1134 did; it will be the sole source for handlers of other purpose.
1135 A last source for handlers may be the MIME type definition itself, if
1136 the \*(UA specific type-marker extension was used when defining the type
1139 (Many of the builtin MIME types do so by default.)
1143 .Va mime-counter-evidence
1144 can be set to improve dealing with faulty MIME part declarations as are
1145 often seen in real-life messages.
1146 E.g., to display a HTML message inline (that is, converted to a more
1147 fancy plain text representation than the builtin converter is capable to
1148 produce) with either of the text-mode browsers
1152 teach \*(UA about MathML documents and make it display them as plain
1153 text, and to open PDF attachments in an external PDF viewer,
1154 asynchronously and with some other magic attached:
1156 .Bd -literal -offset indent
1157 if $features !@ +html-filter
1158 #set pipe-text/html='elinks -force-html -dump 1'
1159 set pipe-text/html='lynx -stdin -dump -force_html'
1160 # Display HTML as plain text instead
1161 #set pipe-text/html=@
1163 mimetype '@ application/mathml+xml mathml'
1164 wysh set pipe-application/pdf='@&=@ \e
1165 trap "rm -f \e"${NAIL_FILENAME_TEMPORARY}\e"" EXIT;\e
1166 trap "trap \e"\e" INT QUIT TERM; exit 1" INT QUIT TERM;\e
1167 mupdf "${NAIL_FILENAME_TEMPORARY}"'
1171 Note: special care must be taken when using such commands as mail
1172 viruses may be distributed by this method: if messages of type
1173 .Ql application/x-sh
1174 or files with the extension
1176 were blindly filtered through the shell, for example, a message sender
1177 could easily execute arbitrary code on the system \*(UA is running on.
1178 For more on MIME, also in respect to sending of messages, see the
1180 .Sx "The mime.types files" ,
1181 .Sx "The Mailcap files"
1186 .\" .Ss "Mailing lists" {{{
1189 \*(UA offers some support to ease handling of mailing lists.
1192 promotes all given arguments to known mailing lists, and
1194 sets their subscription attribute, creating them first as necessary.
1199 automatically, but only resets the subscription attribute.)
1200 Using the commands without arguments will show (a subset of) all
1201 currently defined mailing lists.
1206 can be used to mark out messages with configured list addresses
1207 in the header display.
1210 \*(OPally mailing lists may also be specified as (extended) regular
1211 expressions, which allows matching of many addresses with a single
1213 However, all fully qualified list addresses are matched via a fast
1214 dictionary, whereas expressions are placed in (a) list(s) which is
1215 (are) matched sequentially.
1217 .Bd -literal -offset indent
1218 set followup-to followup-to-honour=ask-yes reply-to-honour=ask-yes
1219 wysh mlist a1@b1.c1 a2@b2.c2 '.*@lists\e.c3$'
1220 mlsubscribe a4@b4.c4 exact@lists.c3
1225 .Va followup-to-honour
1227 .Ql Mail-\:Followup-\:To:
1228 header is honoured when the message is being replied to (via
1234 controls whether this header is created when sending mails; it will be
1235 created automatically for a couple of reasons, too, like when the
1237 .Dq mailing list specific
1242 is used to respond to a message with its
1243 .Ql Mail-Followup-To:
1247 A difference in between the handling of known and subscribed lists is
1248 that the address of the sender is usually not part of a generated
1249 .Ql Mail-Followup-To:
1250 when addressing the latter, whereas it is for the former kind of lists.
1251 Usually because there are exceptions: say, if multiple lists are
1252 addressed and not all of them are subscribed lists.
1254 For convenience \*(UA will, temporarily, automatically add a list
1255 address that is presented in the
1257 header of a message that is being responded to to the list of known
1259 Shall that header have existed \*(UA will instead, dependent on the
1261 .Va reply-to-honour ,
1264 for this purpose in order to accept a list administrators' wish that
1265 is supposed to have been manifested like that (but only if it provides
1266 a single address which resides on the same domain as what is stated in
1270 .\" .Ss "Resource files" {{{
1271 .Ss "Resource files"
1273 Upon startup \*(UA reads in several resource files:
1275 .Bl -tag -width ".It Pa _AIL_EXTRA_R_"
1278 System wide initialization file.
1279 Reading of this file can be suppressed, either by using the
1283 command line options, or by setting the
1286 .Ev NAIL_NO_SYSTEM_RC .
1290 File giving initial commands.
1291 A different file can be chosen by setting the
1295 Reading of this file can be suppressed with the
1297 command line option.
1299 .It Va NAIL_EXTRA_RC
1300 Can be used to define an optional startup file to be read after all
1301 other resource files.
1302 It can be used to specify settings that are not understood by other
1304 implementations, for example.
1305 This variable is only honoured when defined in a resource file, e.g.,
1307 .Sx "INTERNAL VARIABLES" .
1311 The content of these files is interpreted as follows:
1314 .Bl -bullet -compact
1316 A lines' leading whitespace is removed.
1318 Empty lines are ignored.
1320 Any other line is interpreted as a command.
1321 It may be spread over multiple input lines if the newline character is
1323 by placing a reverse solidus character
1325 as the last character of the line; whereas any leading whitespace of
1326 follow lines is ignored, trailing whitespace before a escaped newline
1327 remains in the input.
1329 If the line (content) starts with the number sign
1331 then it is a comment-command \(en a real command! \(en and also ignored.
1332 This command is the only form of comment that is understood.
1336 Unless \*(UA is about to enter interactive mode syntax errors that occur
1337 while loading these files are treated as errors and cause program exit.
1338 More files with syntactically equal content can be
1340 The following, saved in a file, would be an examplary content:
1342 .Bd -literal -offset indent
1343 # This line is a comment command. And y\e
1344 es, it is really continued here.
1351 .\" .Ss "Character sets" {{{
1352 .Ss "Character sets"
1354 \*(OP \*(UA detects the character set of the terminal by using
1355 mechanisms that are controlled by the
1360 should give an overview); the \*(UA internal variable
1362 will be set to the detected terminal character set accordingly
1363 and will thus show up in the output of the commands
1369 However, a user supplied
1371 value is not overwritten by this detection mechanism: this
1373 must be used if the detection doesn't work properly,
1374 and it may be used to adjust the name of the locale character set.
1375 E.g., on BSD systems one may use a locale with the character set
1376 ISO8859-1, which is not a valid name for this character set; to be on
1377 the safe side, one may set
1379 to the correct name, which is ISO-8859-1.
1382 Note that changing the value doesn't mean much beside that,
1383 since several aspects of the real character set are implied by the
1384 locale environment of the system,
1385 and that stays unaffected by the content of an overwritten
1388 (This is mostly an issue when interactively using \*(UA, though.
1389 It is actually possible to send mail in a completely
1391 locale environment, an option that \*(UA's test-suite uses excessively.)
1394 If no character set conversion capabilities have been compiled into
1397 doesn't include the term
1401 will be the only supported character set,
1402 it is simply assumed that it can be used to exchange 8-bit messages,
1403 and the rest of this section does not apply;
1404 it may however still be necessary to explicitly set it if automatic
1405 detection fails, since in that case it defaults to the mentioned
1406 .\" (Keep in SYNC: ./nail.1:"Character sets", ./nail.h:CHARSET_*!)
1410 When reading messages, their text is converted into
1412 as necessary in order to display them on the users terminal.
1413 Unprintable characters and invalid byte sequences are detected
1414 and replaced by proper substitution characters (unless the variable
1416 was set once \*(UA was started).
1418 .Va charset-unknown-8bit
1419 to deal with another hairy aspect of message interpretation.
1422 When sending messages all their parts and attachments are classified.
1423 Whereas no character set conversion is performed on those parts which
1424 appear to be binary data,
1425 the character set being used must be declared within the MIME header of
1426 an outgoing text part if it contains characters that do not conform to
1427 the set of characters that are allowed by the email standards.
1428 Permissible values for character sets can be declared using the
1432 which defines a catch-all last-resort fallback character set that is
1433 implicitly appended to the list of character-sets in
1437 When replying to a message and the variable
1438 .Va reply-in-same-charset
1439 is set then the character set of the message being replied to is tried
1441 And it is also possible to make \*(UA work even more closely related to
1442 the current locale setting automatically by using the variable
1443 .Va sendcharsets-else-ttycharset ,
1444 please see there for more information.
1447 All the specified character sets are tried in order unless the
1448 conversion of the part or attachment succeeds.
1449 If none of the tried (8-bit) character sets is capable to represent the
1450 content of the part or attachment,
1451 then the message will not be sent and its text will optionally be
1455 In general, if the message
1456 .Dq Cannot convert from a to b
1457 appears, either some characters are not appropriate for the currently
1458 selected (terminal) character set,
1459 or the needed conversion is not supported by the system.
1460 In the first case, it is necessary to set an appropriate
1462 locale and/or the variable
1466 The best results are usually achieved when \*(UA is run in a UTF-8
1467 locale on a UTF-8 capable terminal, in which case the full Unicode
1468 spectrum of characters is available.
1469 In this setup characters from various countries can be displayed,
1470 while it is still possible to use more simple character sets for sending
1471 to retain maximum compatibility with older mail clients.
1474 On the other hand the POSIX standard defines a locale-independent 7-bit
1475 .Dq portable character set
1476 that should be used when overall portability is an issue, the even more
1477 restricted subset named
1478 .Dq portable filename character set
1479 consisting of A-Z, a-z, 0-9, period
1488 .\" .Ss "Message states" {{{
1489 .Ss "Message states"
1491 \*(UA differentiates in between several different message states;
1492 the current state will be reflected in header summary displays if
1494 is configured to do so (via the internal variable
1496 and messages can also be selected and be acted upon depending on their
1498 .Sx "Specifying messages" ) .
1499 When operating on the system
1501 box or in primary mailboxes opened with the special prefix
1505 special actions, like the automatic moving of messages to the secondary
1507 mailbox may be applied when the mailbox is left (also implicitly via
1508 a successful exit of \*(UA, but not if the special command
1510 is used) \(en however, because this may be irritating to users which
1513 mail-user-agents, the default global
1519 variables in order to suppress this behaviour.
1521 .Bl -tag -width ".It Ql _reserved"
1523 Message has neither been viewed nor moved to any other state.
1524 Such messages are retained even in the primary system mailbox.
1527 Message has neither been viewed nor moved to any other state, but the
1528 message was present already when the mailbox has been opened last:
1529 Such messages are retained even in the primary system mailbox.
1532 The message has been processed by one of the following commands:
1552 commands may also cause the next message to be marked as read, depending
1558 command is used, messages that are in the primary system mailbox or in
1559 mailboxes which were opened with the special
1563 state when the mailbox is left will be saved in
1570 The message has been processed by one of the following commands:
1576 can be used to access such messages.
1579 The message has been processed by a
1581 command and it will be retained in its current location.
1584 The message has been processed by one of the following commands:
1590 command is used, messages that are in the primary system mailbox or in
1591 mailboxes which were opened with the special
1595 state when the mailbox is left will be deleted; they will be saved in
1603 .\" .Ss "Specifying messages" {{{
1604 .Ss "Specifying messages"
1611 can be given a list of message numbers as arguments to apply to a number
1612 of messages at once.
1615 deletes messages 1 and 2,
1618 will delete the messages 1 through 5.
1619 In sorted or threaded mode (see the
1623 will delete the messages that are located between (and including)
1624 messages 1 through 5 in the sorted/threaded order, as shown in the
1627 Multiple colon modifiers can be joined into one, e.g.,
1629 The following special message names exist:
1631 .Bl -tag -width ".It Ar _n_u"
1637 All old messages (any not in state
1662 All answered messages
1667 All messages marked as draft.
1669 \*(OP All messages classified as spam.
1671 \*(OP All messages with unsure spam classification.
1673 The current message, the so-called
1676 The message that was previously the current message.
1678 The parent message of the current message,
1679 that is the message with the Message-ID given in the
1681 field or the last entry of the
1683 field of the current message.
1685 The next previous undeleted message,
1686 or the next previous deleted message for the
1689 In sorted/threaded mode,
1690 the next previous such message in the sorted/threaded order.
1692 The next undeleted message,
1693 or the next deleted message for the
1696 In sorted/threaded mode,
1697 the next such message in the sorted/threaded order.
1699 The first undeleted message,
1700 or the first deleted message for the
1703 In sorted/threaded mode,
1704 the first such message in the sorted/threaded order.
1707 In sorted/threaded mode,
1708 the last message in the sorted/threaded order.
1712 selects the message addressed with
1716 is any other message specification,
1717 and all messages from the thread that begins at it.
1718 Otherwise it is identical to
1723 the thread beginning with the current message is selected.
1728 All messages that were included in the message list for the previous
1731 .It Ar / Ns Ar string
1732 All messages that contain
1734 in the subject field (case ignored).
1741 the string from the previous specification of that type is used again.
1743 .It Xo Op Ar @ Ns Ar name-list Ns
1746 All messages that contain the given case-insensitive search
1748 ession; if the \*(OPal regular expression (see
1750 support is available
1752 will be interpreted as (an extended) one if any of the
1754 (extended) regular expression characters is seen.
1756 .Ar @ Ns Ar name-list
1757 part is missing, the search is restricted to the subject field body,
1760 specifies a comma-separated list of header fields to search, as in
1762 .Dl '@to,from,cc@Someone i ought to know'
1764 In order to search for a string that includes a
1766 (commercial at) character the
1768 is effectively non-optional, but may be given as the empty string.
1769 Some special header fields may be abbreviated:
1783 respectively and case-insensitively.
1788 can be used to search in (all of) the header(s) of the message, and the
1797 can be used to perform full text searches \(en whereas the former
1798 searches only the body, the latter also searches the message header.
1800 This message specification performs full text comparison, but even with
1801 regular expression support it is almost impossible to write a search
1802 expression that savely matches only a specific address domain.
1803 To request that the content of the header is treated as a list of
1804 addresses, and to strip those down to the plain email address which the
1805 search expression is to be matched against, prefix the header name
1806 (abbreviation) with a tilde
1809 .Dl @~f@@a\e.safe\e.domain\e.match$
1813 .Dq any substring matches
1816 header, which will match addresses (too) even if
1818 is set (and POSIX says
1819 .Dq any address as shown in a header summary shall be matchable in this form ) ;
1822 variable is set, only the local part of the address is evaluated
1823 for the comparison, not ignoring case, and the setting of
1825 is completely ignored.
1826 For finer control and match boundaries use the
1828 search expression; the \*(OPal IMAP-style
1830 expression can also be used if substring matches are desired.
1834 \*(OP IMAP-style SEARCH expressions may also be used.
1835 This addressing mode is available with all types of folders;
1836 \*(UA will perform the search locally as necessary.
1837 Strings must be enclosed by double quotes
1839 in their entirety if they contain white space or parentheses;
1840 within the quotes, only reverse solidus
1842 is recognized as an escape character.
1843 All string searches are case-insensitive.
1844 When the description indicates that the
1846 representation of an address field is used,
1847 this means that the search string is checked against both a list
1850 .Bd -literal -offset indent
1851 (\*qname\*q \*qsource\*q \*qlocal-part\*q \*qdomain-part\*q)
1856 and the addresses without real names from the respective header field.
1857 These search expressions can be nested using parentheses, see below for
1861 .Bl -tag -compact -width ".It Ar _n_u"
1862 .It Ar ( criterion )
1863 All messages that satisfy the given
1865 .It Ar ( criterion1 criterion2 ... criterionN )
1866 All messages that satisfy all of the given criteria.
1868 .It Ar ( or criterion1 criterion2 )
1869 All messages that satisfy either
1874 To connect more than two criteria using
1876 specifications have to be nested using additional parentheses,
1878 .Ql (or a (or b c)) ,
1882 .Ql ((a or b) and c) .
1885 operation of independent criteria on the lowest nesting level,
1886 it is possible to achieve similar effects by using three separate
1890 .It Ar ( not criterion )
1891 All messages that do not satisfy
1893 .It Ar ( bcc \*q Ns Ar string Ns Ar \*q )
1894 All messages that contain
1896 in the envelope representation of the
1899 .It Ar ( cc \*q Ns Ar string Ns Ar \*q )
1900 All messages that contain
1902 in the envelope representation of the
1905 .It Ar ( from \*q Ns Ar string Ns Ar \*q )
1906 All messages that contain
1908 in the envelope representation of the
1911 .It Ar ( subject \*q Ns Ar string Ns Ar \*q )
1912 All messages that contain
1917 .It Ar ( to \*q Ns Ar string Ns Ar \*q )
1918 All messages that contain
1920 in the envelope representation of the
1923 .It Ar ( header name \*q Ns Ar string Ns Ar \*q )
1924 All messages that contain
1929 .It Ar ( body \*q Ns Ar string Ns Ar \*q )
1930 All messages that contain
1933 .It Ar ( text \*q Ns Ar string Ns Ar \*q )
1934 All messages that contain
1936 in their header or body.
1937 .It Ar ( larger size )
1938 All messages that are larger than
1941 .It Ar ( smaller size )
1942 All messages that are smaller than
1946 .It Ar ( before date )
1947 All messages that were received before
1949 which must be in the form
1953 denotes the day of the month as one or two digits,
1955 is the name of the month \(en one of
1956 .Ql Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ,
1959 is the year as four digits, e.g.,
1963 All messages that were received on the specified date.
1964 .It Ar ( since date )
1965 All messages that were received since the specified date.
1966 .It Ar ( sentbefore date )
1967 All messages that were sent on the specified date.
1968 .It Ar ( senton date )
1969 All messages that were sent on the specified date.
1970 .It Ar ( sentsince date )
1971 All messages that were sent since the specified date.
1973 The same criterion as for the previous search.
1974 This specification cannot be used as part of another criterion.
1975 If the previous command line contained more than one independent
1976 criterion then the last of those criteria is used.
1980 .\" .Ss "On URL syntax and credential lookup" {{{
1981 .Ss "On URL syntax and credential lookup"
1983 \*(IN For accessing protocol-specific resources usage of Uniform
1984 Resource Locators (URL, RFC 1738) has become omnipresent.
1985 \*(UA expects and understands URLs in the following form;
1988 denote optional parts, optional either because there also exist other
1989 ways to define the information in question or because support of the
1990 part is protocol-specific (e.g.,
1992 is used by the IMAP protocol but not by POP3);
1997 are specified they must be given in URL percent encoded form (RFC 3986;
2005 .Dl PROTOCOL://[USER[:PASSWORD]@]server[:port][/path]
2008 Note that these \*(UA URLs most often don't conform to any real
2009 standard, but instead represent a normalized variant of RFC 1738 \(en
2010 they are not used in data exchange but only meant as a compact,
2011 easy-to-use way of defining and representing information in
2012 a well-known notation.
2015 Many internal variables of \*(UA exist in multiple versions, called
2016 variable chains for the rest of this document: the plain
2021 .Ql variable-USER@HOST .
2028 had been specified in the respective URL, otherwise it refers to the plain
2034 that had been found when doing the user chain lookup as is described
2037 will never be in URL percent encoded form, whether it came from an URL
2038 or not; i.e., values of
2039 .Sx "INTERNAL VARIABLES"
2040 must not be URL percent encoded.
2043 For example, whether an hypothetical URL
2044 .Ql smtp://hey%3Ayou@our.house
2045 had been given that includes a user, or whether the URL was
2046 .Ql smtp://our.house
2047 and the user had been found differently, to lookup the variable chain
2048 .Va smtp-use-starttls
2049 \*(UA first looks for whether
2050 .Ql smtp-\:use-\:starttls-\:hey:you@our.house
2051 is defined, then whether
2052 .Ql smtp-\:use-\:starttls-\:our.house
2053 exists before finally ending up looking at the plain variable itself.
2056 \*(UA obeys the following logic scheme when dealing with the
2057 necessary credential information of an account:
2063 has been given in the URL the variables
2067 are looked up; if no such variable(s) can be found then \*(UA will,
2068 when enforced by the \*(OPal variables
2069 .Va netrc-lookup-HOST
2076 specific entry which provides a
2078 name: this lookup will only succeed if unambiguous (one possible matching
2081 It is possible to load encrypted
2086 If there is still no
2088 then \*(UA will fall back to the user who is supposed to run \*(UA,
2089 the identity of which has been fixated during \*(UA startup and is
2090 known to be a valid user on the current host.
2093 Authentication: unless otherwise noted this will lookup the
2094 .Va PROTOCOL-auth-USER@HOST , PROTOCOL-auth-HOST , PROTOCOL-auth
2095 variable chain, falling back to a protocol-specific default should this
2101 has been given in the URL, then if the
2103 has been found through the \*(OPal
2105 that may have already provided the password, too.
2106 Otherwise the variable chain
2107 .Va password-USER@HOST , password-HOST , password
2108 is looked up and used if existent.
2110 Afterwards the complete \*(OPal variable chain
2111 .Va netrc-lookup-USER@HOST , netrc-lookup-HOST , netrc-lookup
2115 cache is searched for a password only (multiple user accounts for
2116 a single machine may exist as well as a fallback entry without user
2117 but with a password).
2119 If at that point there is still no password available, but the
2120 (protocols') chosen authentication type requires a password, then in
2121 interactive mode the user will be prompted on the terminal.
2126 S/MIME verification works relative to the values found in the
2130 header field(s), which means that the values of
2131 .Va smime-sign , smime-sign-cert , smime-sign-include-certs
2133 .Va smime-sign-message-digest
2134 will not be looked up using the
2138 chains from above but instead use the corresponding values from the
2139 message that is being worked on.
2140 In unusual cases multiple and different
2144 combinations may therefore be involved \(en on the other hand those
2145 unusual cases become possible.
2146 The usual case is as short as:
2149 .Dl set smtp=smtp://USER:PASS@HOST smtp-use-starttls \e
2150 .Dl \ \ \ \ smime-sign smime-sign-cert=+smime.pair
2155 contains complete example configurations.
2158 .\" .Ss "On terminal control and line editor" {{{
2159 .Ss "On terminal control and line editor"
2161 \*(OP \*(UA can be configured to support a line editor,
2162 history lists that can be saved in between sessions,
2163 and terminal control to improve interactive usage experience.
2164 For the former one may either link against an external library
2165 .Pf ( Xr readline 3 ;
2166 behaviour of \*(UA may differ slightly),
2167 or enable the builtin Mailx-Line-Editor (MLE), which should work in all
2168 environments which comply to the ISO C standard
2170 and which will support wide glyphs if possible (the necessary
2171 functionality had been removed from ISO C, but was included in
2173 Prevent usage of a line editor in interactive mode by setting the
2175 .Va line-editor-disable .
2180 feature is available then input from line editor prompts will be saved
2181 in a history list that can be searched in and be expanded from.
2182 Such saving can be prevented by prefixing input with any amount of
2184 Aspects of history, like allowed content, maximum size etc., can be
2185 configured with the variables
2188 .Va history-gabby-persist
2193 \*(OP Terminal control will be realized through one of the standard
2195 libraries, either the
2197 or, alternatively, the
2199 both of which will be initialized to work with the environment variable
2201 Terminal control will enhance or enable interactive usage aspects, e.g.,
2202 .Sx "Coloured display" ,
2203 and extend behaviour of the MLE, which may learn the key-sequences of
2204 keys like the cursor and function keys, and which will automatically
2207 alternative screen shall the terminal support it.
2208 The internal variable
2210 can be used to overwrite settings or to learn (correct(ed)) keycodes.
2211 Actual interaction with the chosen library can be disabled completely by
2212 setting the internal variable
2213 .Va termcap-disable ,
2214 which may be necessary for proper operation on the actual terminal;
2216 will be queried regardless, even if the \*(OPal support for the
2217 libraries has not been enabled at configuration time.
2220 \*(OP The builtin \*(UA line editor MLE supports the following
2221 operations; the notation
2223 stands for the combination of the
2225 key plus the mentioned character, e.g.,
2228 .Dq hold down control key and press the A key .
2229 Especially without termcap support setting respective entries in
2231 will help shall the MLE misbehave.
2232 The MLE also supports several
2237 .Bl -tag -compact -width "Ql _M"
2239 Go to the start of the line.
2241 Move the cursor backward one character.
2243 Forward delete the character under the cursor;
2244 quits \*(UA if used on the empty line unless the
2248 Go to the end of the line.
2250 Move the cursor forward one character.
2253 Cancel current operation, full reset.
2254 If there is an active history search or tabulator expansion then this
2255 command will first reset that, reverting to the former line content;
2256 thus a second reset is needed for a full reset in this case.
2257 In all cases \*(UA will reset a possibly used multibyte character input
2263 backward delete one character.
2267 .Dq horizontal tabulator :
2268 try to expand the word before the cursor, also supporting \*(UA
2275 complete this line of input.
2277 Delete all characters from the cursor to the end of the line.
2281 \*(OP Go to the next history entry.
2286 \*(OP Go to the previous history entry.
2288 \*(OP Complete the current line from (the remaining older) history entries.
2295 Prompts for a Unicode character to be inserted.
2297 Delete the characters from the one preceding the cursor to the preceding
2300 Move the cursor forward one word boundary.
2302 Move the cursor backward one word boundary.
2306 If the keycodes are known then the left and right cursor keys will map to
2310 respectively, the up and down cursor keys will map to
2314 and the Home/End/PgUp/PgDown keys will call the
2316 command with the respective arguments
2322 (i.e., perform scrolling through the header summary list).
2323 Also the up and down cursor keys should invoke
2325 for up- and downwards movement if they are used while the
2330 .\" .Ss "Coloured display" {{{
2331 .Ss "Coloured display"
2333 \*(OP \*(UA can be configured to support a coloured display and font
2334 attributes by emitting ANSI / ISO 6429 SGR (select graphic rendition)
2336 Usage of colours and font attributes solely depends upon the
2337 capability of the detected terminal type that is defined by the
2338 environment variable
2340 and which can be fine-tuned by the user via the internal variable
2344 On top of what \*(UA knows about the terminal the boolean variable
2346 defines whether the actually applicable colour and font attribute
2347 sequences should also be generated when output is going to be paged
2348 through the external program defined by the environment variable
2353 This is not enabled by default because different pager programs need
2354 different command line switches or other configuration in order to
2355 support those sequences.
2356 \*(UA however knows about some widely used pagers and in a clean
2357 environment it is often enough to simply set
2359 please refer to that variable for more on this topic.
2364 is set then any active usage of colour and font attribute sequences
2365 is suppressed, but without affecting possibly established
2370 To define and control colours and font attributes a single multiplexer
2371 command family exists:
2373 shows or defines colour mappings for the given colour type (e.g.,
2376 can be used to remove mappings of a given colour type.
2377 Since colours are only available in interactive mode, it may make
2378 sense to conditionalize the colour setup by encapsulating it with
2381 .Bd -literal -offset indent
2382 if terminal && $features =@ +colour
2383 colour iso view-msginfo ft=bold,fg=green
2384 colour iso view-header ft=bold,fg=red "from,subject"
2385 colour iso view-header fg=red
2387 uncolour iso view-header from,subject
2388 colour iso view-header ft=bold,fg=magenta,bg=cyan
2389 colour 256 view-header ft=bold,fg=208,bg=230 subject,from
2390 colour mono view-header ft=bold
2391 colour mono view-header ft=bold,ft=reverse subject,from
2395 .\" }}} (DESCRIPTION)
2398 .\" .Sh COMMANDS {{{
2401 Each command is typed on a line by itself,
2402 and may take arguments following the command word.
2403 Command names may be abbreviated, in which case the first command that
2404 matches the given prefix will be used.
2407 can be used to show the list of all commands, either alphabetically
2408 sorted or in prefix search order (these don't match, also because the
2409 POSIX standard prescribes a set of abbreviations); a more verbose
2410 listing will be produced if either of
2415 \*(OPally the command
2419 when given an argument, will show a documentation string for the
2420 command matching the expanded argument, as in
2422 which should be a shorthand of
2426 For commands which take message lists as arguments, the next message
2427 forward that satisfies the command's requirements will be used shall no
2428 explicit message list have been specified.
2429 If there are no messages forward of the current message,
2430 the search proceeds backwards,
2431 and if there are no good messages at all,
2432 \*(UA shows an error message and aborts the command.
2433 \*(ID Non-message-list arguments can be quoted using the following methods:
2436 .Bl -bullet -compact -offset indent
2438 An argument can be enclosed between paired double-quotes
2443 any white space, shell word expansion, or reverse solidus characters
2444 (except as described next) within the quotes are treated literally as
2445 part of the argument.
2446 A double-quote will be treated literally within single-quotes and vice
2448 Inside such a quoted string the actually used quote character can be
2449 used nonetheless by escaping it with a reverse solidus
2455 An argument that is not enclosed in quotes, as above, can usually still
2456 contain space characters if those spaces are reverse solidus escaped, as in
2460 A reverse solidus outside of the enclosing quotes is discarded
2461 and the following character is treated literally as part of the argument.
2466 Some commands which don't take message-list arguments can also be
2467 prefixed with the special keyword
2469 to choose \*(INible behaviour, and some new commands support only the
2470 new quoting style (without that keyword) and are flagged \*(NQ.
2471 In the future \*(UA will (mostly) use
2473 compatible argument parsing:
2474 Non-message-list arguments can be quoted using the following shell-style
2475 mechanisms: the escape character, single-quotes, double-quotes and
2476 dollar-single-quotes; any unquoted number sign
2478 starts a comment that ends argument processing.
2479 The overall granularity of error reporting and diagnostics, also
2480 regarding function arguments and their content, will improve.
2484 .Bl -bullet -compact -offset indent
2486 The literal value of any character can be preserved by preceding it
2487 with the escape character reverse solidus
2491 will cause variable expansion of the given name: \*(UA
2492 .Sx "INTERNAL VARIABLES"
2495 (shell) variables can be accessed through this mechanism, brace
2496 enclosing the name is supported.
2499 Arguments which are enclosed in
2500 .Ql 'single-\:quotes'
2501 retain their literal value.
2502 A single-quote cannot occur within single-quotes.
2505 The literal value of all characters enclosed in
2506 .Ql \(dqdouble-\:quotes\(dq
2507 is retained, with the exception of dollar
2509 which will cause variable expansion, as above, backquote (grave accent)
2511 (which not yet means anything special), reverse solidus
2513 which will escape any of the characters dollar
2515 (to prevent variable expansion), backquote (grave accent)
2519 (to prevent ending the quote) and reverse solidus
2521 (to prevent escaping, i.e., to embed a reverse solidus character as-is),
2522 but has no special meaning otherwise.
2525 Arguments enclosed in
2526 .Ql $'dollar-\:single-\:quotes'
2527 extend normal single quotes in that reverse solidus escape sequences are
2528 expanded as follows:
2530 .Bl -tag -compact -width "Ql \eNNN"
2536 an escape character.
2538 an escape character.
2550 emits a reverse solidus character.
2554 double quote (escaping is optional).
2556 eight-bit byte with the octal value
2558 (one to three octal digits), optionally with an additional
2561 A 0 byte will suppress further output for the quoted argument.
2563 eight-bit byte with the hexadecimal value
2565 (one or two hexadecimal characters).
2566 A 0 byte will suppress further output for the quoted argument.
2568 the Unicode / ISO-10646 character with the hexadecimal codepoint value
2570 (one to eight hexadecimal digits) \(em note that Unicode defines the
2571 maximum code to be ever supported as
2576 This escape is only supported in locales which support Unicode (see
2577 .Sx "Character sets" ) ,
2578 in other cases the sequence will remain unexpanded unless the given code
2579 point is ASCII compatible.
2580 The character NUL will suppress further output for the quoted argument.
2584 except it takes only one to four hexadecimal digits.
2589 This is a mechanism that allows usage of the non-printable (ASCII and
2590 compatible) control codes 0 to 31: to be able to create a printable
2591 representation the numeric value 64 is added to the control code of
2592 desire, and the resulting ASCII character set code point is then
2593 printed, e.g., BEL is
2594 .Ql 7 + 64 = 71 = G .
2595 Often circumflex notation is used for the visualization purpose, e.g,
2597 but the reverse solid notation has been standardized:
2599 The control code NUL
2601 ends argument processing without producing further output.
2603 Non-standard extension: expand the given variable name, as above.
2604 Brace enclosing the name is supported.
2606 Not yet supported, just to raise awareness: Non-standard extension.
2612 .Sy Compatibility notes:
2613 \*(ID Note these are new mechanisms which are not supported by all
2615 Round-tripping (feeding in things shown in list modes again) are not yet
2616 stable or possible at all.
2617 On new-style command lines it is wise to quote semicolon
2621 characters in order to ensure upward compatibility: the author would
2622 like to see things like
2623 .Ql ? echo $'trouble\tahead' | cat >> in_the_shell.txt
2625 .Ql ? top 2 5 10; type 3 22
2627 Before \*(UA will switch entirely to shell-style argument parsing there
2628 will be a transition phase where using
2630 will emit obsoletion warnings.
2631 E.g., the following are equivalent:
2633 .Bd -literal -offset indent
2634 mlist @any\e\e.where\e\e.example\e\e.com
2635 wysh mlist '@any\e.where\e.example\e.com' # This is a comment
2636 wysh mlist $'@any\e\e\ex2Ewhere\e\e.example\e\e\e56com' # A comment
2637 wysh mlist "@any\e.where\e.example\e.com"
2641 In any event an unquoted reverse solidus at the end of a command line is
2642 discarded and the next line continues the command.
2643 \*(ID Note that line continuation is handled before the above parsing is
2644 applied, i.e., the parsers documented above will see merged lines.
2645 Filenames, where expected, are subsequently subjected to the following
2646 transformations, in sequence:
2649 .Bl -bullet -compact -offset indent
2651 If the filename begins with an unquoted plus sign, and the
2653 variable is defined,
2654 the plus sign will be replaced by the value of the
2656 variable followed by a solidus.
2659 variable is unset or is set to null, the filename will be unchanged.
2662 Meta expansions are applied to the filename: a leading tilde
2664 character will be replaced by the expansion of
2666 except when followed by a valid user name, in which case the home
2667 directory of the given user is used instead.
2672 will be replaced by the expansion of the variable, if possible; \*(UA
2673 .Sx "INTERNAL VARIABLES"
2676 (shell) variables can be accessed through this mechanism, and the usual
2677 escape mechanism has to be applied to prevent interpretation.
2678 If the fully expanded filename results in multiple pathnames and the
2679 command is expecting only one file, an error results.
2681 In interactive context, in order to allow simple value acceptance (via
2683 arguments will usually be displayed in a properly quoted form, e.g., a file
2684 .Ql diet\e is \ecurd.txt
2686 .Ql 'diet\e is \ecurd.txt' .
2690 The following commands are available:
2692 .Bl -tag -width ".Ic _ccount"
2699 ) command which follows.
2703 The comment-command causes the entire line to be ignored.
2705 this really is a normal command which' purpose is to discard its
2708 indicating special character, which means that, e.g., trailing comments
2709 on a line are not possible.
2713 Goes to the next message in sequence and types it
2719 Display the preceding message, or the n'th previous message if given
2720 a numeric argument n.
2724 Show the current message number (the
2729 Show a brief summary of commands.
2730 \*(OP Given an argument a synopsis for the command in question is
2731 shown instead; commands can be abbreviated in general and this command
2732 can be used to see the full expansion of an abbreviation including the
2733 synopsis, try, e.g.,
2738 and see how the output changes.
2748 Interprets the remainder of the word as a macro name and passes it
2753 is a shorter synonym for
2754 .Ql call Ar mymacro .
2758 (ac) Creates, selects or lists (an) account(s).
2759 Accounts are special incarnations of
2761 macros and group commands and variable settings which together usually
2762 arrange the environment for the purpose of creating an email account.
2763 Different to normal macros settings which are covered by
2765 \(en here by default enabled! \(en will not be reverted before the
2770 (case-insensitive) always exists, and all but it can be deleted via
2773 Without arguments a listing of all defined accounts is shown.
2774 With one argument the given account is activated: the system
2776 box of that account will be activated (as via
2778 and a possibly installed
2781 The two argument form is identical to defining a macro as via
2783 .Bd -literal -offset indent
2785 set folder=~/mail MAIL=+syste.mbox record=+sent.mbox
2786 set from='myname@myisp.example (My Name)'
2787 set smtp=smtp://mylogin@smtp.myisp.example
2793 (a) With no arguments, shows all currently-defined aliases.
2794 With one argument, shows that alias.
2795 With more than one argument,
2796 creates a new alias or appends to an existing one.
2798 can be used to delete aliases.
2802 (alt) Manage a list of alternate addresses / names of the active user,
2803 members of which will be removed from recipient lists when replying to
2806 variable is not set).
2807 If arguments are given the set of alternate names is replaced by them,
2808 without arguments the current set is displayed.
2812 Takes a message list and marks each message as having been answered.
2813 This mark has no technical meaning in the mail system;
2814 it just causes messages to be marked in the header summary,
2815 and makes them specially addressable.
2819 Calls a macro that has been created via
2824 (ch) Change the working directory to
2826 or the given argument.
2832 \*(OP Only applicable to S/MIME signed messages.
2833 Takes a message list and a file name and saves the certificates
2834 contained within the message signatures to the named file in both
2835 human-readable and PEM format.
2836 The certificates can later be used to send encrypted messages to the
2837 respective message senders by setting
2838 .Va smime-encrypt-USER@HOST
2843 (ch) Change the working directory to
2845 or the given argument.
2851 Only applicable to threaded mode.
2852 Takes a message list and makes all replies to these messages invisible
2853 in header summaries, unless they are in state
2859 \*(OP\*(NQ Manage colour mappings for the type of colour given as the
2860 (case-insensitive) first argument, which must be one of
2862 for 256-colour terminals,
2867 for the standard 8-colour ANSI / ISO 6429 color palette and
2871 for monochrome terminals.
2872 Monochrome terminals cannot deal with colours, but only (some) font
2876 Without further arguments the list of all currently defined mappings
2877 for the given colour type is shown (as a special case giving
2881 will iterate over all types in order).
2882 Otherwise the second argument defines the mappable slot, the third
2883 argument a (comma-separated list of) colour and font attribute
2884 specification(s), and the optional fourth argument can be used to
2885 specify a precondition: if conditioned mappings exist they are tested in
2886 (creation) order unless a (case-insensitive) match has been found, and
2887 the default mapping (if any has been established) will only be chosen as
2889 The types of precondition available depend on the mappable slot, the
2890 following of which exist:
2893 Mappings prefixed with
2895 are used for the \*(OPal builtin Mailx-Line-Editor (MLE, see
2896 .Sx "On terminal control and line editor" )
2897 and don't support preconditions.
2899 .Bl -tag -compact -width view-partinfo
2901 This mapping is used for the position indicator that is visible when
2902 a line cannot be fully displayed on the screen.
2909 Mappings prefixed with
2911 are used in header summaries, and they all understand the preconditions
2913 (the current message) and
2915 for elder messages (only honoured in conjunction with
2916 .Va datefield-markout-older ) .
2918 .Bl -tag -compact -width view-partinfo
2920 This mapping is used for the
2922 that can be created with the
2926 formats of the variable
2929 For the complete header summary line except the
2931 and the thread structure.
2933 For the thread structure which can be created with the
2935 format of the variable
2940 Mappings prefixed with
2942 are used when displaying messages.
2944 .Bl -tag -compact -width view-partinfo
2946 This mapping is used for so-called
2948 lines, which are MBOX file format specific header lines.
2951 A comma-separated list of headers to which the mapping applies may be
2952 given as a precondition; if the \*(OPal regular expression support is
2953 available then if any of the
2955 (extended) regular expression characters is seen the precondition will
2956 be evaluated as (an extended) one.
2958 For the introductional message info line.
2959 .It Cd view-partinfo
2960 For MIME part info lines.
2964 The following (case-insensitive) colour definitions and font attributes
2965 are understood, multiple of which can be specified in a comma-separated
2975 It is possible (and often applicable) to specify multiple font
2976 attributes for a single mapping.
2979 foreground colour attribute:
2989 To specify a 256-color mode a decimal number colour specification in
2990 the range 0 to 255, inclusive, is supported, and interpreted as follows:
2992 .Bl -tag -compact -width "999 - 999"
2994 the standard ISO 6429 colors, as above.
2996 high intensity variants of the standard colors.
2998 216 colors in tuples of 6.
3000 grayscale from black to white in 24 steps.
3002 .Bd -literal -offset indent
3004 fg() { printf "\e033[38;5;${1}m($1)"; }
3005 bg() { printf "\e033[48;5;${1}m($1)"; }
3007 while [ $i -lt 256 ]; do fg $i; i=$(($i + 1)); done
3008 printf "\e033[0m\en"
3010 while [ $i -lt 256 ]; do bg $i; i=$(($i + 1)); done
3011 printf "\e033[0m\en"
3015 background colour attribute (see
3017 for possible values).
3021 Mappings may be removed with the command
3023 For a generic overview see the section
3024 .Sx "Coloured display" .
3029 (C) Copy messages to files whose names are derived from the author of
3030 the respective message and don't mark them as being saved;
3031 otherwise identical to
3036 (c) Copy messages to the named file and don't mark them as being saved;
3037 otherwise identical to
3042 \*(NQ With no arguments, shows all currently-defined custom headers.
3043 With one argument, shows that custom header.
3044 With more than one argument, creates a new or replaces an existing
3045 custom header with the name given as the first argument, the content of
3046 which being defined by the concatenated remaining arguments.
3048 can be used to delete custom headers.
3049 \*(ID Overwriting of automatically managed headers is neither supported
3051 Defined custom headers will be injected into newly composed or forwarded
3054 .Dl customhdr OpenPGP id=12345678; url=http://www.YYY.ZZ
3058 may also be used to inject custom headers; it is covered by
3063 Show the name of the current working directory.
3067 \*(OP For unencrypted messages this command is identical to
3069 Encrypted messages are first decrypted, if possible, and then copied.
3073 \*(OP For unencrypted messages this command is identical to
3075 Encrypted messages are first decrypted, if possible, and then copied.
3079 Without arguments the current list of macros, including their content,
3080 is shown, otherwise a macro is defined.
3081 A macro definition is a sequence of commands in the following form:
3082 .Bd -literal -offset indent
3091 A defined macro can be invoked explicitly by using the
3095 commands, or implicitly if a macro hook is triggered, e.g., a
3097 Note that interpretation of
3099 depends on how (i.e.,
3101 normal macro, folder hook, hook, account switch) the macro is invoked.
3102 Macros can be deleted via
3106 Macro behaviour, including option localization, will change in v15.
3107 Please be aware of that and possibly embed a version check in a resource
3112 (d) Marks the given message list as
3114 Deleted messages will neither be saved in
3116 nor will they be available for most other commands.
3128 Deletes the current message and displays the next message.
3129 If there is no next message, \*(UA says
3136 up or down by one message when given
3140 argument, respectively.
3144 Takes a message list and marks each given message as a draft.
3145 This mark has no technical meaning in the mail system;
3146 it just causes messages to be marked in the header summary,
3147 and makes them specially addressable.
3151 (ec) Echoes its arguments after applying
3153 expansions and filename transformations, as documented for
3158 (e) Point the text editor (as defined in
3160 at each message from the given list in turn.
3161 Modified contents are discarded unless the
3168 .Ic if Ns / Ns Ic elif Ns / Ns Ic else Ns / Ns Ic endif
3169 conditional \(em if the condition of a preceding
3171 was false, check the following condition and execute the following block
3172 if it evaluates true.
3177 .Ic if Ns / Ns Ic elif Ns / Ns Ic else Ns / Ns Ic endif
3178 conditional \(em if none of the conditions of the preceding
3182 commands was true, the
3188 (en) Marks the end of an
3189 .Ic if Ns / Ns Ic elif Ns / Ns Ic else Ns / Ns Ic endif
3190 conditional execution block.
3195 \*(NQ \*(UA has a strict notion about which variables are
3196 .Sx "INTERNAL VARIABLES"
3197 and which are managed in the program
3199 Since some of the latter are a vivid part of \*(UAs functioning,
3200 however, they are transparently integrated into the normal handling of
3201 internal variables via
3205 To integrate other environment variables of choice into this
3206 transparent handling, and also to export internal variables into the
3207 process environment where they normally are not, a
3209 needs to become established with this command, as in, e.g.,
3212 .Dl environ link PERL5LIB from TZ
3215 Afterwards changing such variables with
3217 will cause automatic updates of the program environment, and therefore
3218 be inherited by newly created child processes.
3219 Sufficient system support provided (it was in BSD as early as 1987, and
3220 is standardized since Y2K) removing such variables with
3222 will remove them also from the program environment, but in any way
3223 the knowledge they ever have been
3226 Note this implies that
3228 may cause loss of links.
3233 will remove an existing link, but leaves the variables as such intact.
3234 Additionally the subcommands
3238 are provided, which work exactly the same as the documented commands
3242 but (additionally) link the variable(s) with the program environment and
3243 thus immediately export them to, or remove them from (if possible),
3244 respectively, the program environment.
3249 \*(OP Since \*(UA uses the console as a user interface it can happen
3250 that messages scroll by too fast to become recognized.
3251 Optionally an error message ring queue is available which stores
3252 duplicates of any error message and notifies the user in interactive
3253 sessions whenever a new error has occurred.
3254 The queue is finite: if its maximum size is reached any new message
3255 replaces the eldest.
3258 can be used to manage this message queue: if given
3260 or no argument the queue will be displayed and cleared,
3262 will only clear all messages from the queue.
3266 (ex or x) Exit from \*(UA without changing the active mailbox and skip
3267 any saving of messages in
3269 as well as a possibly tracked line editor history file.
3273 Show the list of features that have been compiled into \*(UA.
3274 (Outputs the contents of the variable
3281 but open the mailbox readonly.
3285 (fi) The file command switches to a new mailbox.
3286 Without arguments it shows status information of the current mailbox.
3287 If an argument is given, it will write out changes (such as deletions)
3288 the user has made and open a new mailbox.
3289 Some special conventions are recognized for the
3293 .Bl -tag -compact -offset indent -width ".Ar %:__lespec"
3295 (number sign) means the previous file,
3297 (percent sign) means the invoking user's system
3301 means the primary system mailbox of
3303 (and never the value of
3305 regardless of its actual setting),
3307 (ampersand) means the invoking user's
3317 expands to the same value as
3319 but the file is handled as a primary system mailbox by, e.g., the
3323 commands, meaning that messages that have been read in the current
3324 session will be moved to the
3326 mailbox instead of simply being flagged as read.
3329 If the name matches one of the strings defined with the command
3331 it is replaced by its long form and expanded.
3332 If the name ends with
3337 it is treated as being compressed with
3342 respectively, and transparently handled through an intermediate
3343 (un)compression step (using a temporary file) with the according
3344 facility, sufficient support provided.
3345 Likewise, if the named file doesn't exist, but a file with one of the
3346 mentioned compression extensions does, then the name is automatically
3347 expanded and the compressed file is used.
3349 Otherwise, if the name ends with an extension for which
3350 .Va file-hook-load-EXTENSION
3352 .Va file-hook-save-EXTENSION
3353 variables are set, then the given hooks will be used to load and save
3355 and \*(UA will work with an intermediate temporary file.
3357 MBOX files (flat file-based mailboxes) are generally locked during file
3358 operations in order to avoid inconsistencies due to concurrent
3360 \*(OPal Mailbox files which \*(UA treats as system
3362 boxes or primary mailboxes will also be protected by so-called dotlock
3363 files, the traditional way of mail spool file locking: for any file
3367 will be created for the duration of the synchronization \(em
3368 as necessary a privilege-separated dotlock child process will be used
3369 to accommodate for necessary privilege adjustments in order to create
3370 the dotlock file in the same directory
3371 and with the same user and group identities as the file of interest.
3374 for fine-tuning the handling of MBOX files.
3378 refers to a directory with the subdirectories
3383 then it is treated as a folder in
3385 format; \*(ID the variable
3387 can be used to control the format of yet non-existent folders.
3390 .Dl \*(IN protocol://[user[:password]@]host[:port][/path]
3391 .Dl \*(OU protocol://[user@]host[:port][/path]
3393 is taken as an Internet mailbox specification.
3394 The \*(OPally supported protocols are
3398 (POP3 with SSL/TLS encrypted transport).
3401 part is valid only for IMAP; there it defaults to
3403 Also see the section
3404 .Sx "On URL syntax and credential lookup" .
3408 contains special characters, in particular
3412 they must be escaped in URL notation \(en the command
3414 can be used to show the necessary conversion.
3418 Takes a message list and marks the messages as
3420 ged for urgent/special attention.
3421 This mark has no technical meaning in the mail system;
3422 it just causes messages to be highlighted in the header summary,
3423 and makes them specially addressable.
3432 With no arguments, list the names of the folders in the folder directory.
3433 With an existing folder as an argument,
3434 lists the names of folders below the named folder.
3440 but saves the message in a file named after the local part of the first
3441 recipient's address (instead of in
3448 but saves the message in a file named after the local part of the first
3449 recipient's address (instead of in
3456 but responds to all recipients regardless of the
3461 .It Ic followupsender
3464 but responds to the sender only regardless of the
3480 (f) Takes a list of message specifications and displays a summary of
3481 their message headers, as via
3483 An alias of this command is
3486 .Sx "Specifying messages" .
3492 but saves the message in a file named after the local part of the
3493 recipient's address (instead of in
3498 Takes a message and the address of a recipient
3499 and forwards the message to him.
3500 The text of the original message is included in the new one,
3501 with the value of the
3503 variable preceding it.
3508 commands specify which header fields are included in the new message.
3509 Only the first part of a multipart message is included unless the
3510 .Va forward-as-attachment
3514 is set recipient addresses will be stripped from comments, names etc.
3518 Specifies which header fields are to be ignored with the command
3520 This command has no effect when the
3521 .Va forward-as-attachment
3526 Specifies which header fields are to be retained with the command
3531 This command has no effect when the
3532 .Va forward-as-attachment
3537 Define or list command aliases, so-called ghosts.
3538 Without arguments a list of all currently known aliases is shown.
3539 With one argument the expansion of the given alias is shown.
3540 With two or more arguments a command alias is defined or updated: the
3541 first argument is the name under which the remaining command line should
3542 be accessible, the content of which can be just about anything.
3543 A ghost can be used everywhere a normal command can be used, but always
3544 takes precedence; any arguments that are given to the command alias are
3545 joined onto the alias content, and the resulting string forms the
3546 command line that is, in effect, executed.
3549 .Bd -literal -offset indent
3551 `ghost': no such alias: "xx"
3554 ghost xx "echo hello,"
3563 (h) Show the current group of headers, the size of which depends on
3566 and the style of which can be adjusted with the variable
3568 If a message-specification is given the group of headers containing the
3569 first message therein is shown and the message at the top of the screen
3584 the list of history entries;
3587 argument selects and shows the respective history entry \(en
3590 to accept it, and the history entry will become the new history top.
3591 The default mode if no arguments are given is
3598 Takes a message list and marks each message therein to be saved in the
3603 Does not override the
3606 \*(UA deviates from the POSIX standard with this command, because a
3608 command issued after
3610 will display the following message, not the current one.
3615 (i) Part of the nestable
3616 .Ic if Ns / Ns Ic elif Ns / Ns Ic else Ns / Ns Ic endif
3617 conditional execution construct \(em if the given condition is true then
3618 the encapsulated block is executed.
3619 POSIX only supports the (case-insensitive) conditions
3624 end, all remaining conditions are non-portable extensions; note that
3625 falsely specified conditions cause the execution of the entire
3626 conditional construct until the (matching) closing
3628 command to be suppressed.
3629 The syntax of the nestable
3631 conditional execution construct requires that each condition and syntax
3632 element is surrounded by whitespace.
3634 .Bd -literal -offset indent
3643 The (case-insensitive) condition
3645 erminal will evaluate to true if the standard input is a terminal, i.e.,
3646 in interactive sessions.
3647 Another condition can be any boolean value (see the section
3648 .Sx "INTERNAL VARIABLES"
3649 for textual boolean representations) to mark an enwrapped block as
3652 .Dq always execute .
3653 It is possible to check
3654 .Sx "INTERNAL VARIABLES"
3657 variables for existence or compare their expansion against a user given
3658 value or another variable by using the
3660 .Pf ( Dq variable next )
3661 conditional trigger character;
3662 a variable on the right hand side may be signalled using the same
3664 The variable names may be enclosed in a pair of matching braces.
3667 The available comparison operators are
3671 (less than or equal to),
3677 (greater than or equal to),
3681 (is substring of) and
3683 (is not substring of).
3684 The values of the left and right hand side are treated as strings and
3685 are compared 8-bit byte-wise, ignoring case according to the rules of
3686 the US-ASCII encoding (therefore, dependent on the active locale,
3687 possibly producing false results for strings in the locale encoding).
3688 Except for the substring checks the comparison will instead be performed
3689 arithmetically if both, the user given value as well as the variable
3690 content, can be parsed as numbers (integers).
3691 An unset variable is treated as the empty string.
3694 When the \*(OPal regular expression support is available, the additional
3700 They treat the right hand side as an extended regular expression that is
3701 matched case-insensitively and according to the active
3703 locale, meaning that strings in the locale encoding should be matched
3707 Conditions can be joined via AND-OR lists (where the AND operator is
3709 and the OR operator is
3711 which have equal precedence and will be evaluated with left
3712 associativity, thus using the same syntax that is known for the
3714 It is also possible to form groups of conditions and lists by enclosing
3715 them in pairs of brackets
3716 .Ql [\ \&.\&.\&.\ ] ,
3717 which may be interlocked within each other, and also be joined via
3721 The results of individual conditions and entire groups may be modified
3722 via unary operators: the unary operator
3724 will reverse the result.
3726 .Bd -literal -offset indent
3730 if $ttycharset == "UTF-8"
3731 echo *ttycharset* is set to UTF-8, case-insensitively
3735 echo These two variables are equal
3737 if $version-major >= 15
3738 echo Running a new version..
3739 if $features =@ +regex
3740 if $TERM =~ "^xterm\&.*"
3741 echo ..in an X terminal
3744 if [ [ true ] && [ [ ${debug} ] || [ $verbose ] ] ]
3747 if true && $debug || ${verbose}
3748 echo Left associativity, as is known from the shell
3750 if ! ! true && ! [ ! $debug && ! $verbose ]
3751 echo Unary operator support
3759 Without arguments the list of ignored header fields is shown,
3760 otherwise the given list of header fields is added to the ignore list:
3761 Header fields in the ignore list are not shown on the terminal when
3762 a message is displayed.
3763 To display a message in its entirety, use the commands
3774 Shows the names of all available commands, alphabetically sorted.
3775 If given any non-whitespace argument the list will be shown in the order
3776 in which command prefixes are searched.
3779 output is available.
3783 This command can be used to localize changes to variables, meaning that
3784 their state will be reverted to the former one once the covered scope
3786 It can only be used inside of macro definition blocks introduced by
3790 and is interpreted as a boolean (string, see
3791 .Sx "INTERNAL VARIABLES" ) ;
3794 of an account is left once it is switched off again.
3795 .Bd -literal -offset indent
3796 define temporary_settings {
3811 enables change localization and calls
3813 which explicitly resets localization, then any value changes within
3815 will still be reverted by
3817 \*(ID Once the outermost level, the one which enabled localization
3818 first, is left, but no earlier, all adjustments will be unrolled.
3822 Reply to messages that come in via known
3825 .Pf ( Ic mlsubscribe )
3826 mailing lists, or pretend to do so (see
3827 .Sx "Mailing lists" ) :
3830 functionality this will actively resort and even remove message
3831 recipients in order to generate a message that is supposed to be sent to
3833 For example it will also implicitly generate a
3834 .Ql Mail-Followup-To:
3835 header if that seems useful, regardless of the setting of the variable
3842 but saves the message in a file named after the local part of the first
3843 recipient's address (instead of in
3848 (m) Takes a (list of) recipient address(es) as (an) argument(s),
3849 or asks on standard input if none were given;
3850 then collects the remaining mail content and sends it out.
3854 (mb) The given message list is to be sent to
3856 when \*(UA is quit; this is the default action unless the
3859 \*(ID This command can only be used in a primary system mailbox (see
3864 Without any arguments the content of the MIME type cache will displayed.
3865 Otherwise each argument defines a complete MIME type specification of
3866 a type that shall be added (prepended) to the cache.
3867 In any event MIME type sources are loaded first as necessary \(en
3868 .Va mimetypes-load-control
3869 can be used to fine-tune which sources are actually loaded.
3870 Refer to the section on
3871 .Sx "The mime.types files"
3872 for more on MIME type specifications and this topic in general.
3873 MIME type unregistration and cache resets can be triggered with
3878 Without arguments the list of all currently defined mailing lists
3879 (and their attributes, if any) is shown; a more verbose listing will be
3880 produced if either of
3885 Otherwise all given arguments (which need not be quoted except for
3886 whitespace) will be added and henceforth be recognized as mailing lists.
3887 Mailing lists may be removed via the command
3890 If the \*(OPal regular expression support is available then mailing
3891 lists may also be specified as (extended) regular expressions (see
3897 Without arguments the list of all currently defined mailing lists which
3898 have a subscription attribute is shown; a more verbose listing will be
3899 produced if either of
3904 Otherwise this attribute will be set for all given mailing lists,
3905 newly creating them as necessary (as via
3907 Subscription attributes may be removed via the command
3916 but moves the messages to a file named after the local part of the
3917 sender address of the first message (instead of in
3924 but marks the messages for deletion if they were transferred
3931 but also displays ignored header fields and all MIME parts.
3939 on the given messages, even in non-interactive mode and as long as the
3940 standard output is a terminal.
3946 \*(OP When used without arguments or if
3948 has been given the content of the
3950 cache is shown, loading it first as necessary.
3953 then the cache will only be initialized and
3955 will remove its contents.
3956 Note that \*(UA will try to load the file only once, use
3957 .Ql Ic \&\&netrc Ns \:\0\:clear
3958 to unlock further attempts.
3963 .Sx "On URL syntax and credential lookup" ;
3965 .Sx "The .netrc file"
3966 documents the file format in detail.
3970 Checks for new mail in the current folder without committing any changes
3972 If new mail is present, a message is shown.
3976 the headers of each new message are also shown.
3984 Goes to the next message in sequence and types it.
3985 With an argument list, types the next matching message.
3999 If the current folder is accessed via a network connection, a
4001 command is sent, otherwise no operation is performed.
4007 but also displays ignored header fields and all MIME parts.
4015 on the given messages, even in non-interactive mode and as long as the
4016 standard output is a terminal.
4024 but also pipes ignored header fields and all parts of MIME
4025 .Ql multipart/alternative
4030 (pi) Takes a message list and a shell command
4031 and pipes the messages through the command.
4032 Without an argument the current message is piped through the command
4039 every message is followed by a formfeed character.
4060 (q) Terminates the session, saving all undeleted, unsaved messages in
4063 preserving all messages marked with
4067 or never referenced in the system
4069 box, and removing all other messages from the primary system mailbox.
4070 If new mail has arrived during the session,
4072 .Dq You have new mail
4074 If given while editing a mailbox file with the command line flag
4076 then the edit file is rewritten.
4077 A return to the shell is effected,
4078 unless the rewrite of edit file fails,
4079 in which case the user can escape with the exit command.
4093 Removes the named files or directories.
4094 If a name refer to a mailbox, e.g., a Maildir mailbox, then a mailbox
4095 type specific removal will be performed, deleting the complete mailbox.
4096 The user is asked for confirmation in interactive mode.
4100 Takes the name of an existing folder
4101 and the name for the new folder
4102 and renames the first to the second one.
4103 Both folders must be of the same type.
4107 (R) Reply to originator.
4108 Does not reply to other recipients of the original message.
4110 will exchange this command with
4114 is set the recipient address will be stripped from comments, names etc.
4118 (r) Take a message and group-responds to it by addressing the sender
4121 .Va followup-to-honour ,
4124 .Va recipients-in-cc
4125 influence response behaviour.
4128 offers special support for replying to mailing lists.
4131 is set recipient addresses will be stripped from comments, names etc.
4144 but initiates a group-reply regardless of the value of
4151 but responds to the sender only regardless of the value of
4158 but does not add any header lines.
4159 This is not a way to hide the sender's identity,
4160 but useful for sending a message again to the same recipients.
4164 Takes a list of messages and a user name
4165 and sends each message to the named user.
4167 and related header fields are prepended to the new copy of the message.
4185 .It Ic respondsender
4191 (ret) Without arguments the list of retained header fields is shown,
4192 otherwise the given list of header fields is added to the retain list:
4193 Header fields in the retain list are shown on the terminal when
4194 a message is displayed, all other header fields are suppressed.
4195 To display a message in its entirety, use the commands
4204 takes precedence over the mentioned.
4210 but saves the messages in a file named after the local part of the
4211 sender of the first message instead of (in
4213 and) taking a filename argument.
4217 (s) Takes a message list and a filename and appends each message in turn
4218 to the end of the file.
4219 If no filename is given, the
4222 The filename in quotes, followed by the generated character count
4223 is echoed on the user's terminal.
4224 If editing a primary system mailbox the messages are marked for deletion.
4225 Filename interpretation as described for the
4227 command is performed.
4244 Header fields thus marked are filtered out when saving a message by
4246 or when automatically saving to
4248 This command should only be applied to header fields that do not contain
4249 information needed to decode the message,
4250 as MIME content fields do.
4262 Header fields thus marked are the only ones saved with a message when
4265 or when automatically saving to
4270 The use of this command is strongly discouraged since it may strip
4271 header fields that are needed to decode the message correctly.
4275 Takes a message specification (list) and displays a header summary of
4276 all matching messages, as via
4278 This command is an alias of
4281 .Sx "Specifying messages" .
4285 Takes a message list and marks all messages as having been read.
4289 (se) Without arguments this command shows all internal variables which
4290 are currently known to \*(UA (they have been set).
4291 A more verbose listing will be produced if either of
4295 are set, in which case variables may be preceded with a comment line
4296 that gives some context of what \*(UA knows about the given variable.
4298 Otherwise the given variables (and arguments) are set or adjusted.
4299 Arguments are of the form
4301 (no space before or after
4305 if there is no value, i.e., a boolean variable.
4306 Quotation marks may be placed around any part of the assignment
4307 statement to quote blanks or tabs, e.g.,
4309 .Dl set indentprefix='->'
4311 If an argument begins with
4315 the effect is the same as invoking the
4317 command with the remaining part of the variable
4318 .Pf ( Ql unset save ) .
4322 that is known to map to an environment variable will automatically cause
4323 updates in the program environment (unsetting a variable in the
4324 environment requires corresponding system support).
4325 Please use the command
4327 for further environmental control.
4332 .Sx "INTERNAL VARIABLES"
4338 (sh) Invokes an interactive version of the shell.
4342 Without arguments the list of all currently defined shortcuts is
4344 Otherwise all given arguments (which need not be quoted except for
4345 whitespace) are treated as pairs of shortcuts and their expansions,
4346 creating new or changing already existing shortcuts, as necessary.
4347 Shortcuts may be removed via the command
4349 The expansion strings should be in the syntax that has been described
4358 but performs neither MIME decoding nor decryption, so that the raw
4359 message text is shown.
4363 (si) Shows the size in characters of each message of the given
4368 Shows the current sorting criterion when used without an argument.
4369 Otherwise creates a sorted representation of the current folder,
4372 command and the addressing modes such that they refer to messages in
4374 Message numbers are the same as in regular mode.
4378 a header summary in the new order is also displayed.
4379 Automatic folder sorting can be enabled by setting the
4381 variable, as in, e.g.,
4382 .Ql set autosort=thread .
4383 Possible sorting criterions are:
4385 .Bl -tag -compact -offset indent -width "subject"
4387 Sort the messages by their
4389 field, that is by the time they were sent.
4391 Sort messages by the value of their
4393 field, that is by the address of the sender.
4396 variable is set, the sender's real name (if any) is used.
4398 Sort the messages by their size.
4400 \*(OP Sort the message by their spam score, as has been classified by
4403 Sort the messages by their message status.
4405 Sort the messages by their subject.
4407 Create a threaded display.
4409 Sort messages by the value of their
4411 field, that is by the address of the recipient.
4414 variable is set, the recipient's real name (if any) is used.
4419 (so) The source command reads commands from the given file, which is
4420 subject to the usual filename expansions (see introductional words of
4422 If the given argument ends with a vertical bar
4424 then the argument will instead be interpreted as a shell command and
4425 \*(UA will read the output generated by it.
4428 cannot be used from within macros that execute as
4429 .Va folder-hook Ns s
4432 i.e., it can only be called from macros that were
4439 (beside not supporting pipe syntax aka shell command input) is that
4440 this command will not generate an error if the given file argument
4441 cannot be opened successfully.
4442 This can matter in, e.g., resource files, since loading of those is
4443 stopped when an error is encountered.
4447 \*(OP Takes a list of messages and clears their
4453 \*(OP Takes a list of messages and causes the
4455 to forget it has ever used them to train its Bayesian filter.
4456 Unless otherwise noted the
4458 flag of the message is inspected to chose whether a message shall be
4466 \*(OP Takes a list of messages and informs the Bayesian filter of the
4470 This also clears the
4472 flag of the messages in question.
4476 \*(OP Takes a list of messages and rates them using the configured
4477 .Va spam-interface ,
4478 without modifying the messages, but setting their
4480 flag as appropriate; because the spam rating headers are lost the rate
4481 will be forgotten once the mailbox is left.
4482 Refer to the manual section
4484 for the complete picture of spam handling in \*(UA.
4488 \*(OP Takes a list of messages and sets their
4494 \*(OP Takes a list of messages and informs the Bayesian filter of the
4500 flag of the messages in question.
4509 Create a threaded representation of the current folder,
4510 i.\|e. indent messages that are replies to other messages in the header
4511 display and change the
4513 command and the addressing modes such that they refer to messages in the
4515 Message numbers are the same as in unthreaded mode.
4519 a header summary in threaded order is also displayed.
4523 (to) Takes a message list and displays the top few lines of each.
4524 The number of lines shown is controlled by the variable
4529 (tou) Takes a message list and marks the messages for saving in
4531 \*(UA deviates from the POSIX standard with this command,
4534 command will display the following message instead of the current one.
4540 but also displays out ignored header fields and all parts of MIME
4541 .Ql multipart/alternative
4546 (t) Takes a message list and types out each message on the user's
4552 For MIME multipart messages, all parts with a content type of
4556 are shown, the other are hidden except for their headers.
4557 Messages are decrypted and converted to the terminal character set
4562 Delete all given accounts.
4563 An error message is shown if a given account is not defined.
4566 will discard all existing accounts.
4570 (una) Takes a list of names defined by alias commands
4571 and discards the remembered groups of users.
4574 will discard all existing aliases.
4578 Takes a message list and marks each message as not having been answered.
4582 Only applicable to threaded mode.
4583 Takes a message list and makes the message and all replies to it visible
4584 in header summaries again.
4585 When a message becomes the current message,
4586 it is automatically made visible.
4587 Also when a message with collapsed replies is displayed,
4588 all of these are automatically uncollapsed.
4594 mapping for the given colour type (see
4596 for a list of types) and mapping; if the optional precondition argument
4597 is used then only the exact tuple of mapping and precondition is removed.
4600 will remove all mappings (no precondition allowed).
4602 .Sx "Coloured display"
4603 for the general picture.
4607 Deletes the custom headers given as arguments.
4610 will remove all custom headers.
4614 Undefine all given macros.
4615 An error message is shown if a given macro is not defined.
4618 will discard all existing macros.
4622 (u) Takes a message list and marks each message as not being deleted.
4626 Takes a message list and
4632 Takes a message list and marks each message as not being
4637 Removes the header field names from the list of ignored fields for the
4642 will remove all fields.
4646 Removes the header field names from the list of retained fields for the
4651 will remove all fields.
4655 Remove all the given command
4659 will remove all ghosts.
4663 Removes the header field names from the list of ignored fields.
4666 will remove all fields.
4670 Delete all given MIME types, e.g.,
4671 .Ql unmimetype text/plain
4672 will remove all registered specifications for the MIME type
4676 will discard all existing MIME types, just as will
4678 but which also reenables cache initialization via
4679 .Va mimetypes-load-control .
4683 Forget about all the given mailing lists.
4686 will remove all lists.
4691 .It Ic unmlsubscribe
4692 Remove the subscription attribute from all given mailing lists.
4695 will clear the attribute from all lists which have it set.
4706 Takes a message list and marks each message as not having been read.
4710 Removes the header field names from the list of retained fields.
4713 will remove all fields.
4717 Removes the header field names from the list of ignored fields for
4721 will remove all fields.
4725 Removes the header field names from the list of retained fields for
4729 will remove all fields.
4733 (uns) Takes a list of internal variable names and discards their
4734 remembered values; the reverse of
4741 Deletes the shortcut names given as arguments.
4744 will remove all shortcuts.
4748 Disable sorted or threaded mode
4754 return to normal message order and,
4758 displays a header summary.
4768 Decode the given URL-encoded string arguments and show the results.
4769 Note the resulting strings may not be valid in the current locale, see
4774 URL-encode the given arguments and show the results.
4775 Because the arguments effectively are in the character set of the
4776 current locale the results will vary accordingly unless the input solely
4777 consists of characters in the portable character set, see
4778 .Sx "Character sets" .
4782 Edit the values of or create the given variable(s) in the
4784 Boolean variables cannot be edited.
4788 This command produces the same output as the listing mode of
4792 ity adjustments, but only for the given variables.
4796 \*(OP Takes a message list and verifies each message.
4797 If a message is not a S/MIME signed message,
4798 verification will fail for it.
4799 The verification process checks if the message was signed using a valid
4801 if the message sender's email address matches one of those contained
4802 within the certificate,
4803 and if the message content has been altered.
4807 (v) Takes a message list and invokes the display editor on each message.
4808 Modified contents are discarded unless the
4814 (w) For conventional messages the body without all headers is written.
4815 The output is decrypted and converted to its native format as necessary.
4816 If the output file exists, the text is appended.
4817 If a message is in MIME multipart format its first part is written to
4818 the specified file as for conventional messages,
4819 and the user is asked for a filename to save each other part.
4820 For convience saving of each part may be skipped by giving an empty value;
4821 the same result can also be achieved by writing it to
4823 For the second and subsequent parts a leading
4825 character causes the part to be piped to the remainder of the user input
4826 interpreted as a shell command;
4827 otherwise the user input is expanded as usually for folders,
4828 e.g., tilde expansion is performed.
4829 In non-interactive mode, only the parts of the multipart message
4830 that have a filename given in the part header are written,
4831 the others are discarded.
4832 The original message is never marked for deletion in the originating
4835 the contents of the destination file are overwritten if the file
4837 No special handling of compressed files is performed.
4846 \*(UA presents message headers in windowfuls as described under the
4849 This command scrolls to the next window of messages.
4850 If an argument is given,
4851 it specifies the window to use.
4852 A number prefixed by
4856 indicates that the window is calculated in relation to the current position.
4857 A number without a prefix specifies an absolute window number,
4860 lets \*(UA scroll to the last window of messages.
4866 but scrolls to the next or previous window that contains at least one
4875 .\" .Sh TILDE ESCAPES {{{
4878 Here is a summary of the tilde escapes,
4879 which are used to perform special functions when composing messages.
4880 Tilde escapes are only recognized at the beginning of lines.
4883 is somewhat of a misnomer since the actual escape character can be
4884 changed by adjusting the option
4887 .Bl -tag -width ".Ic __ filename"
4890 Insert the string of text in the message prefaced by a single
4892 (If the escape character has been changed,
4893 that character must be doubled
4894 in order to send it at the beginning of a line.)
4897 .It Ic ~! Ar command
4898 Execute the indicated shell
4900 then return to the message.
4904 Same effect as typing the end-of-file character.
4907 .It Ic ~: Ar \*(UA-command Ns \0or Ic ~_ Ar \*(UA-command
4908 Execute the given \*(UA command.
4909 Not all commands, however, are allowed.
4913 Write a summary of command escapes.
4916 .It Ic ~< Ar filename
4921 .It Ic ~<! Ar command
4923 is executed using the shell.
4924 Its standard output is inserted into the message.
4927 .It Ic ~@ Op Ar filename...
4928 With no arguments, edit the attachment list interactively.
4929 If an attachment's file name is left empty,
4930 that attachment is deleted from the list.
4931 When the end of the attachment list is reached,
4932 \*(UA will ask for further attachments until an empty name is given.
4933 If a given file name solely consists of the number sign
4935 followed by a valid message number of the currently active mailbox, then
4936 the given message is attached as a MIME
4938 and the rest of this section does not apply.
4940 If character set conversion has been compiled into \*(UA, then this mode
4941 gives the user the option to specify input and output character sets,
4942 unless the file extension indicates binary content, in which case \*(UA
4943 asks whether this step shall be skipped for the attachment in question.
4944 If not skipped, then the charset that succeeds to represent the
4945 attachment data will be used in the
4947 MIME parameter of the mail message:
4949 .Bl -bullet -compact
4951 If input and output character sets are specified, then the conversion is
4952 performed on the fly.
4953 The user will be asked repeatedly until the desired conversion succeeds.
4955 If only an output character set is specified, then the input is assumed
4958 charset and will be converted to the given output charset on the fly.
4959 The user will be asked repeatedly until the desired conversion succeeds.
4961 If no character sets are specified at all then the algorithm that is
4962 documented in the section
4963 .Sx "Character sets"
4964 is applied, but directly and on the fly.
4965 The user will be asked repeatedly until the desired conversion succeeds.
4967 Finally, if an input-, but no output character set is specified, then no
4968 conversion is ever performed, but the
4970 MIME parameter value will still be set to the user input.
4972 The character set selection loop can be left by typing
4974 i.e., causing an interrupt.
4975 .\" \*(OU next sentence
4976 Note that before \*(UA version 15.0 this terminates the entire
4977 current attachment selection, not only the character set selection.
4980 Without character set conversion support, \*(UA will ask for the input
4981 character set only, and it'll set the
4983 MIME parameter value to the given input, if any;
4984 if no user input is seen then the
4986 character set will be used for the parameter value instead.
4987 Note that the file extension check isn't performed in this mode, since
4988 no conversion will take place anyway.
4990 Note that in non-interactive mode, for reproduceabilities sake, there
4991 will always be two questions for each attachment, regardless of whether
4992 character set conversion is available and what the file extension is.
4993 The first asks for the filename, and the second asks for the input
4994 character set to be passed through to the corresponding MIME parameter;
4995 no conversion will be tried if there is input to the latter question,
4996 otherwise the usual conversion algorithm, as above, is applied.
4997 For message attachments, the answer to the second question is completely
5002 arguments are specified for the
5004 command they are treated as a file list of
5006 -style quoted arguments, optionally also separated by commas, which are
5007 expanded and then appended to the existing list of message attachments.
5008 Message attachments can only be added via the first method.
5009 In this mode the (text) attachments are assumed to be in
5011 encoding, and will be evaluated as documented in the section
5012 .Sx "Character sets" .
5016 Inserts the string contained in the
5019 .Ql Ic ~i Ns \0Sign ) .
5020 The escape sequences tabulator
5028 Inserts the string contained in the
5031 .Ql Ic ~i Ns \0sign ) .
5032 The escape sequences tabulator
5039 .It Ic ~b Ar name ...
5040 Add the given names to the list of blind carbon copy recipients.
5043 .It Ic ~c Ar name ...
5044 Add the given names to the list of carbon copy recipients.
5048 Read the file specified by the
5050 variable into the message.
5054 Invoke the text editor on the message collected so far.
5055 After the editing session is finished,
5056 the user may continue appending text to the message.
5059 .It Ic ~F Ar messages
5060 Read the named messages into the message being sent, including all
5061 message headers and MIME parts.
5062 If no messages are specified, read in the current message.
5065 .It Ic ~f Ar messages
5066 Read the named messages into the message being sent.
5067 If no messages are specified, read in the current message.
5071 lists are used to modify the message headers.
5072 For MIME multipart messages,
5073 only the first displayable part is included.
5077 Edit the message header fields
5082 by typing each one in turn and allowing the user to edit the field.
5083 The default values for these fields originate from the
5091 Edit the message header fields
5097 by typing each one in turn and allowing the user to edit the field.
5100 .It Ic ~i Ar variable
5101 Insert the value of the specified variable into the message,
5102 adding a newline character at the end.
5103 The message remains unaltered if the variable is unset or empty.
5104 The escape sequences tabulator
5111 .It Ic ~M Ar messages
5112 Read the named messages into the message being sent,
5115 If no messages are specified, read the current message.
5118 .It Ic ~m Ar messages
5119 Read the named messages into the message being sent,
5122 If no messages are specified, read the current message.
5126 lists are used to modify the message headers.
5127 For MIME multipart messages,
5128 only the first displayable part is included.
5132 Display the message collected so far,
5133 prefaced by the message header fields
5134 and followed by the attachment list, if any.
5138 Abort the message being sent,
5139 copying it to the file specified by the
5146 .It Ic ~R Ar filename
5147 Read the named file into the message, indented by
5151 .It Ic ~r Ar filename
5152 Read the named file into the message.
5156 Cause the named string to become the current subject field.
5159 .It Ic ~t Ar name ...
5160 Add the given name(s) to the direct recipient list.
5163 .It Ic ~U Ar messages
5164 Read in the given / current message(s) excluding all headers, indented by
5168 .It Ic ~u Ar messages
5169 Read in the given / current message(s), excluding all headers.
5173 Invoke an alternate editor (defined by the
5175 option) on the message collected so far.
5176 Usually, the alternate editor will be a screen editor.
5177 After the editor is quit,
5178 the user may resume appending text to the end of the message.
5181 .It Ic ~w Ar filename
5182 Write the message onto the named file.
5184 the message is appended to it.
5190 except that the message is not saved at all.
5193 .It Ic ~| Ar command
5194 Pipe the message through the specified filter command.
5195 If the command gives no output or terminates abnormally,
5196 retain the original text of the message.
5199 is often used as a rejustifying filter.
5204 .\" .Sh INTERNAL VARIABLES {{{
5205 .Sh "INTERNAL VARIABLES"
5207 Internal \*(UA variables are controlled via the
5211 commands; prefixing a variable name with the string
5215 has the same effect as using
5221 Creation or editing of variables can be performed in the
5226 will give more insight on the given variable(s), and
5228 when called without arguments, will show a listing of all variables.
5229 Some well-known variables will also become inherited from the
5232 implicitly, others can be explicitly imported with the command
5234 and henceforth share the said properties.
5237 Two different kind of internal variables exist.
5238 There are boolean variables, which can only be in one of the two states
5242 and value variables with a(n optional) string value.
5243 For the latter proper quoting is necessary upon assignment time, the
5244 introduction of the section
5246 documents the supported quoting rules.
5248 .Bd -literal -offset indent
5249 wysh set one=val\e 1 two="val 2" \e
5250 three='val "3"' four=$'val \e'4\e''
5251 varshow one two three four
5252 unset one two three four
5256 Dependent upon the actual option the string values will be interpreted
5257 as numbers, colour names, normal text etc., but there also exists
5258 a special kind of string value, the
5259 .Dq boolean string ,
5260 which must either be a decimal integer (in which case
5264 and any other value is true) or any of the (case-insensitive) strings
5269 for a false boolean and
5274 for a true boolean; a special kind of boolean string is the
5276 which is a boolean string that can optionally be prefixed with the
5277 (case-insensitive) term
5281 which causes prompting of the user in interactive mode, with the given
5282 boolean as the default value.
5284 .\" .Ss "Initial settings" {{{
5285 .\" (Keep in SYNC: ./nail.h:okeys, ./nail.rc, ./nail.1:"Initial settings")
5286 .Ss "Initial Settings"
5288 The standard POSIX 2008/Cor 1-2013 mandates the following initial
5294 .Pf no Va autoprint ,
5308 .Pf no Va ignoreeof ,
5310 .Pf no Va keepsave ,
5312 .Pf no Va outfolder ,
5317 (note that \*(UA deviates from the standard by using
5321 special prompt escape results in
5329 .Pf no Va sendwait ,
5338 Notes: \*(UA doesn't support the
5340 variable \(en use command line options or
5341 .Va sendmail-arguments
5342 to pass options through to a MTA.
5343 And the default global
5345 file (which is loaded unless the
5347 command line flag has been used or the
5348 .Ev NAIL_NO_SYSTEM_RC
5349 environment variable is set) bends those initial settings a bit, e.g.,
5350 it sets the variables
5355 to name a few, calls
5357 etc., and should thus be taken into account.
5360 .\" .Ss "Variables" {{{
5363 .Bl -tag -width ".It Va _utoprin_"
5365 .It Va add-file-recipients
5366 \*(BO When file or pipe recipients have been specified,
5367 mention them in the corresponding address fields of the message instead
5368 of silently stripping them from their recipient list.
5369 By default such addressees are not mentioned.
5373 \*(BO Causes only the local part to be evaluated
5374 when comparing addresses.
5378 \*(BO Causes messages saved in
5380 to be appended to the end rather than prepended.
5381 This should always be set.
5385 \*(BO Causes \*(UA to prompt for the subject of each message sent.
5386 If the user responds with simply a newline,
5387 no subject field will be sent.
5391 \*(BO Causes the prompts for
5395 lists to appear after the message has been edited.
5399 \*(BO If set, \*(UA asks for files to attach at the end of each message,
5400 shall the list be found empty at that time.
5401 An empty line finalizes the list.
5405 \*(BO Causes the user to be prompted for carbon copy recipients
5406 (at the end of each message if
5410 are set) shall the list be found empty (at that time).
5411 An empty line finalizes the list.
5415 \*(BO Causes the user to be prompted for blind carbon copy
5416 recipients (at the end of each message if
5420 are set) shall the list be found empty (at that time).
5421 An empty line finalizes the list.
5425 \*(BO\*(OP Causes the user to be prompted if the message is to be
5426 signed at the end of each message.
5429 variable is ignored when this variable is set.
5433 \*(BO Alternative name for
5440 .It Va attachment-ask-content-description , \
5441 attachment-ask-content-disposition , \
5442 attachment-ask-content-id , \
5443 attachment-ask-content-type
5444 \*(BO If set then the user will be prompted for some attachment
5445 information when editing the attachment list.
5446 It is advisable to not use these but for the first of the variables;
5447 even for that it has to be noted that the data is used
5453 A sequence of characters to display in the
5457 as shown in the display of
5459 each for one type of messages (see
5460 .Sx "Message states" ) ,
5461 with the default being
5464 .Ql NU\ \ *HMFAT+\-$~
5467 variable is set, in the following order:
5469 .Bl -tag -compact -offset indent -width ".It Ql _"
5491 start of a collapsed thread.
5493 an uncollapsed thread (TODO ignored for now).
5497 classified as possible spam.
5503 Specifies a list of recipients to which a blind carbon copy of each
5504 outgoing message will be sent automatically.
5508 Specifies a list of recipients to which a carbon copy of each outgoing
5509 message will be sent automatically.
5513 \*(BO Causes threads to be collapsed automatically when threaded mode
5520 \*(BO Causes the delete command to behave like
5522 thus, after deleting a message the next one will be typed automatically.
5526 \*(BO\*(OB Causes threaded mode (see the
5528 command) to be entered automatically when a folder is opened.
5530 .Ql autosort=thread .
5534 Causes sorted mode (see the
5536 command) to be entered automatically with the value of this option as
5537 sorting method when a folder is opened, e.g.,
5538 .Ql set autosort=thread .
5542 \*(BO Enables the substitution of
5544 by the contents of the last command line in shell escapes.
5547 .It Va batch-exit-on-error
5548 \*(BO If the batch mode has been enabled via the
5550 command line option, then this variable will be consulted whenever \*(UA
5551 completes one operation (returns to the command prompt); if it is set
5552 then \*(UA will terminate if the last operation generated an error.
5556 \*(BO Causes automatic display of a header summary after executing a
5558 command, and thus complements the standard variable
5560 which controls header summary display on program startup.
5561 It is only meaningful if
5567 \*(BO Sets some cosmetical features to traditional BSD style;
5568 has the same affect as setting
5570 and all other variables prefixed with
5572 it also changes the meaning of the \*(UA specific
5575 escape sequence and changes behaviour of
5577 (which doesn't exist in BSD).
5581 \*(BO Changes the letters shown in the first column of a header
5582 summary to traditional BSD style.
5586 \*(BO Changes the display of columns in a header summary to traditional
5591 \*(BO Changes some informational messages to traditional BSD style.
5597 field to appear immediately after the
5599 field in message headers and with the
5601 .Sx "TILDE ESCAPES" .
5605 The value that should appear in the
5609 MIME header fields when no character set conversion of the message data
5611 This defaults to US-ASCII, and the chosen character set should be
5612 US-ASCII compatible.
5616 \*(OP The default 8-bit character set that is used as an implicit last
5617 member of the variable
5619 This defaults to UTF-8.
5620 If no character set conversion capabilities are available in \*(UA then
5621 the only supported character set is
5623 Refer to the section
5624 .Sx "Character sets"
5625 for the complete picture of character set conversion in \*(UA.
5628 .It Va charset-unknown-8bit
5629 \*(OP RFC 1428 specifies conditions when internet mail gateways shall
5631 the content of a mail message by using a character set with the name
5633 Because of the unclassified nature of this character set \*(UA will not
5634 be capable to convert this character set to any other character set.
5635 If this variable is set any message part which uses the character set
5637 is assumed to really be in the character set given in the value,
5638 otherwise the (final) value of
5640 is used for this purpose.
5642 This variable will also be taken into account if a MIME type (see
5643 .Sx "The mime.types files" )
5644 of a MIME message part that uses the
5646 character set is forcefully treated as text.
5650 The default value for the
5655 .It Va colour-disable
5656 \*(BO\*(OP Forcefully disable usage of colours.
5657 Also see the section
5658 .Sx "Coloured display" .
5662 \*(BO\*(OP Whether colour shall be used for output that is paged through
5664 Note that pagers may need special flags, e.g.,
5672 in order to support colours.
5673 Often doing manual adjustments is unnecessary since \*(UA may perform
5674 adjustments dependend on the value of the environment variable
5676 (see there for more).
5680 In a(n interactive) terminal session, then if this valued option is set
5681 it'll be used as a threshold to determine how many lines the given
5682 output has to span before it will be displayed via the configured
5686 can be forced by setting this to the value
5688 setting it without a value will deduce the current height of the
5689 terminal screen to compute the treshold (see
5697 \*(OB A variable counterpart of the
5699 command (see there for documentation), interpreted as a comma-separated
5700 list of custom headers to be injected, to include commas in the header
5701 bodies escape them with reverse solidus, e.g.:
5703 .Dl set customhdr='Hdr1: Body1-1\e, Body1-2, Hdr2: Body2'
5709 the message date, if any is to be displayed according to the format of
5711 is by default taken from the
5713 line of the message.
5714 If this variable is set the date as given in the
5716 header field is used instead, converted to local time.
5717 To control the display format of the date assign a valid
5722 format should not be used, because \*(UA doesn't take embedded newlines
5723 into account when calculating how many lines fit onto the screen.)
5725 .Va datefield-markout-older .
5728 .It Va datefield-markout-older
5729 This option, when set in addition to
5733 messages (concept is rather comparable to the
5735 option of the POSIX utility
5737 The content interpretation is identical to
5742 \*(BO Enables debug messages and obsoletion warnings, disables the
5743 actual delivery of messages and also implies
5749 .It Va disposition-notification-send
5751 .Ql Disposition-Notification-To:
5752 header (RFC 3798) with the message.
5756 .\" TODO .It Va disposition-notification-send-HOST
5758 .\".Va disposition-notification-send
5759 .\" for SMTP accounts on a specific host.
5760 .\" TODO .It Va disposition-notification-send-USER@HOST
5762 .\".Va disposition-notification-send
5763 .\"for a specific account.
5767 \*(BO When dot is set, a period
5769 on a line by itself during message input in (interactive) compose mode
5770 will be treated as end-of-message (in addition to the normal end-of-file
5779 .It Va dotlock-ignore-error
5780 \*(BO\*(OP Synchronization of mailboxes which \*(UA treats as system
5781 mailboxes (see the command
5783 will be protected with so-called dotlock files\(emthe traditional mail
5784 spool file locking method\(emin addition to system file locking.
5785 Because \*(UA ships with a privilege-separated dotlock creation program
5786 that should always be able to create such a dotlock file there is no
5787 good reason to ignore dotlock file creation errors, and thus these are
5788 fatal unless this variable is set.
5792 \*(BO If this variable is set then the editor is started automatically
5793 when a message is composed in interactive mode, as if the
5799 variable is implied for this automatically spawned editor session.
5803 \*(BO When a message is edited while being composed,
5804 its header is included in the editable text.
5814 fields are accepted within the header, other fields are ignored.
5818 \*(BO When entering interactive mode \*(UA normally writes
5819 .Dq \&No mail for user
5820 and exits immediately if a mailbox is empty or doesn't exist.
5821 If this option is set \*(UA starts even with an empty or nonexistent
5822 mailbox (the latter behaviour furtherly depends upon
5828 Suggestion for the MIME encoding to use in outgoing text messages
5830 Valid values are the default
5831 .Ql quoted-printable ,
5836 may cause problems when transferring mail messages over channels that
5837 are not ESMTP (RFC 1869) compliant.
5838 If there is no need to encode a message,
5840 transfer mode is always used regardless of this variable.
5841 Binary data is always encoded as
5846 If defined, the first character of this option
5847 gives the character to use in place of
5850 .Sx "TILDE ESCAPES" .
5854 If not set then file and command pipeline targets are not allowed,
5855 and any such address will be filtered out, giving a warning message.
5856 If set without a value then all possible recipient address
5857 specifications will be accepted \(en see the section
5858 .Sx "On sending mail, and non-interactive mode"
5860 To accept them, but only in interactive mode, or when tilde commands
5861 were enabled explicitly by using one of the command line options
5865 set this to the (case-insensitive) value
5867 (note right now this is actually like setting
5868 .Ql restrict,-all,+name,+addr ) .
5870 In fact the value is interpreted as a comma-separated list of values.
5873 then the existence of disallowed specifications is treated as a hard
5874 send error instead of only filtering them out.
5875 The remaining values specify whether a specific type of recipient
5876 address specification is allowed (optionally indicated by a plus sign
5878 prefix) or disallowed (prefixed with a hyphen
5882 addresses all possible address specifications,
5886 command pipeline targets,
5888 plain user names and (MTA) aliases (\*(OB
5890 may be used as an alternative syntax to
5895 These kind of values are interpreted in the given order, so that
5896 .Ql restrict,\:fail,\:+file,\:-all,\:+addr
5897 will cause hard errors for any non-network address recipient address
5898 unless \*(UA is in interactive mode or has been started with the
5902 command line option; in the latter case(s) any address may be used, then.
5906 Unless this variable is set additional mail-transfer-agent (MTA)
5907 arguments from the command line, as can be given after a
5909 separator, are ignored due to safety reasons.
5910 However, if set to the special (case-insensitive) value
5912 then the presence of additional MTA arguments is treated as a hard
5913 error that causes \*(UA to exit with failure status.
5914 A lesser strict variant is the otherwise identical
5916 which does accept such arguments in interactive mode, or if tilde
5917 commands were enabled explicitly by using one of the command line options
5924 \*(RO Information on the features compiled into \*(UA \(en the content
5925 of this variable is identical to the output of the command
5930 \*(BO This option reverses the meanings of a set of reply commands,
5931 turning the lowercase variants, which by default address all recipients
5932 included in the header of a message
5933 .Pf ( Ic reply , respond , followup )
5934 into the uppercase variants, which by default address the sender only
5935 .Pf ( Ic Reply , Respond , Followup )
5938 .Ic replysender , respondsender , followupsender
5940 .Ic replyall , respondall , followupall
5941 are not affected by the current setting of
5946 .It Va file-hook-load-EXTENSION , file-hook-save-EXTENSION
5947 It is possible to install file hooks which will be used by the
5949 command in order to be able to transparently handle (through an
5950 intermediate temporary file) files with specific
5952 s: the variable values can include shell snippets and are expected to
5953 write data to standard output / read data from standard input,
5955 \*(ID The variables may not be changed while there is a mailbox
5957 .Bd -literal -offset indent
5958 set file-hook-load-xy='echo >&2 XY-LOAD; gzip -cd' \e
5959 file-hook-save-xy='echo >&2 XY-SAVE; gzip -c' \e
5960 record=+null-sent.xy
5965 The default path under which mailboxes are to be saved:
5966 file names that begin with the plus-sign
5968 will be expanded by prefixing them with the value of this variable.
5969 The same special syntax conventions as documented for the
5971 command may be used; if the non-empty value doesn't start with a solidus
5975 will be prefixed automatically.
5976 If unset or the empty string any
5978 prefixing file names will remain unexpanded.
5982 This variable can be set to the name of a
5984 macro which will be called whenever a
5987 The macro will also be invoked when new mail arrives,
5988 but message lists for commands executed from the macro
5989 only include newly arrived messages then.
5991 are activated by default in a folder hook, causing the covered settings
5992 to be reverted once the folder is left again.
5995 Macro behaviour, including option localization, will change in v15.
5996 Please be aware of that and possibly embed a version check in a resource
6000 .It Va folder-hook-FOLDER
6005 Unlike other folder specifications, the fully expanded name of a folder,
6006 without metacharacters, is used to avoid ambiguities.
6007 However, if the mailbox resides under
6011 specification is tried in addition, e.g., if
6015 (and thus relative to the user's home directory) then
6016 .Pa /home/usr1/mail/sent
6018 .Ql folder-hook-/home/usr1/mail/sent
6019 first, but then followed by
6020 .Ql folder-hook-+sent .
6024 \*(BO Controls whether a
6025 .Ql Mail-Followup-To:
6026 header is generated when sending messages to known mailing lists.
6028 .Va followup-to-honour
6030 .Ic mlist , mlsubscribe , reply
6035 .It Va followup-to-honour
6037 .Ql Mail-Followup-To:
6038 header is honoured when group-replying to a message via
6042 This is a quadoption; if set without a value it defaults to
6052 .It Va forward-as-attachment
6053 \*(BO Original messages are normally sent as inline text with the
6056 and only the first part of a multipart message is included.
6057 With this option messages are sent as unmodified MIME
6059 attachments with all of their parts included.
6063 The address (or a list of addresses) to put into the
6065 field of the message header, quoting RFC 5322:
6066 the author(s) of the message, that is, the mailbox(es) of the person(s)
6067 or system(s) responsible for the writing of the message.
6068 If replying to messages these addresses are handled as if they were in
6072 If the machine's hostname is not valid at the Internet (for example at
6073 a dialup machine) then either this variable or
6078 adds even more fine-tuning capabilities),
6082 contains more than one address,
6085 variable is required (according to the standard RFC 5322).
6089 \*(BO When replying to or forwarding a message \*(UA normally removes
6090 the comment and name parts of email addresses.
6091 If this variable is set such stripping is not performed,
6092 and comments, names etc. are retained.
6096 The string to put before the text of a message with the
6100 .Va forward-as-attachment
6103 .Dq -------- Original Message --------
6104 if unset; No heading is put if it is set to the empty string.
6108 \*(BO Causes the header summary to be written at startup and after
6109 commands that affect the number of messages or the order of messages in
6110 the current folder; enabled by default.
6111 The command line option
6117 complements this and controls header summary display on folder changes.
6122 A format string to use for the summary of
6124 similar to the ones used for
6127 Format specifiers in the given string start with a percent character
6129 and may be followed by an optional decimal number indicating the field
6130 width \(em if that is negative, the field is to be left-aligned.
6131 Valid format specifiers are:
6134 .Bl -tag -compact -offset indent -width "_%%_"
6136 A plain percent character.
6139 a space character but for the current message
6141 for which it expands to
6145 a space character but for the current message
6147 for which it expands to
6150 \*(OP The spam score of the message, as has been classified via the
6153 Shows only a replacement character if there is no spam support.
6155 Message attribute character (status flag); the actual content can be
6159 The date when the message was received, or the date found in the
6163 variable is set (optionally to a date display format string).
6165 The indenting level in threaded mode.
6167 The address of the message sender.
6169 The message thread tree structure.
6170 (Note that this format doesn't support a field width.)
6172 The number of lines of the message, if available.
6176 The number of octets (bytes) in the message, if available.
6178 Message subject (if any).
6180 Message subject (if any) in double quotes.
6182 Message recipient flags: is the addressee of the message a known or
6183 subscribed mailing list \(en see
6188 The position in threaded/sorted order.
6192 .Ql %>\&%a\&%m\ %-18f\ %16d\ %4l/%\-5o\ %i%-s ,
6194 .Ql %>\&%a\&%m\ %20-f\ \ %16d\ %3l/%\-5o\ %i%-S
6205 .It Va headline-bidi
6206 Bidirectional text requires special treatment when displaying headers,
6207 because numbers (in dates or for file sizes etc.) will not affect the
6208 current text direction, in effect resulting in ugly line layouts when
6209 arabic or other right-to-left text is to be displayed.
6210 On the other hand only a minority of terminals is capable to correctly
6211 handle direction changes, so that user interaction is necessary for
6213 Note that extended host system support is required nonetheless, e.g.,
6214 detection of the terminal character set is one precondition;
6215 and this feature only works in an Unicode (i.e., UTF-8) locale.
6217 In general setting this variable will cause \*(UA to encapsulate text
6218 fields that may occur when displaying
6220 (and some other fields, like dynamic expansions in
6222 with special Unicode control sequences;
6223 it is possible to fine-tune the terminal support level by assigning
6225 no value (or any value other than
6230 will make \*(UA assume that the terminal is capable to properly deal
6231 with Unicode version 6.3, in which case text is embedded in a pair of
6232 U+2068 (FIRST STRONG ISOLATE) and U+2069 (POP DIRECTIONAL ISOLATE)
6234 In addition no space on the line is reserved for these characters.
6236 Weaker support is chosen by using the value
6238 (Unicode 6.3, but reserve the room of two spaces for writing the control
6239 sequences onto the line).
6244 select Unicode 1.1 support (U+200E, LEFT-TO-RIGHT MARK); the latter
6245 again reserves room for two spaces in addition.
6249 \*(OP If a line editor is available then this can be set to
6250 name the (expandable) path of the location of a permanent history file.
6253 .It Va history-gabby
6254 \*(BO\*(OP Add more entries to the history as is normally done.
6257 .It Va history-gabby-persist
6258 \*(BO\*(OP \*(UA's own MLE will not save the additional
6260 entries in persistent storage unless this variable is set.
6261 On the other hand it will not loose the knowledge of whether
6262 a persistent entry was gabby or not.
6268 \*(OP If a line editor is available this value restricts the
6269 amount of history entries that are saved into a set and valid
6271 A value of less than 0 disables this feature;
6272 note that loading and incorporation of
6274 upon program startup can also be suppressed by doing this.
6275 If unset or 0, a default value will be used.
6276 Dependent on the available line editor this will also define the
6277 number of history entries in memory;
6278 it is also editor-specific whether runtime updates of this value will
6283 \*(BO This option is used to hold messages in the system
6285 box, and it is set by default.
6289 Use this string as hostname when expanding local addresses instead of
6290 the value obtained from
6301 transport is not used then it is normally the responsibility of the MTA
6302 to create these fields, \*(IN in conjunction with
6306 also influences the results;
6307 you should produce some test messages with the desired combination of
6316 \*(BO\*(OP Can be used to turn off the automatic conversion of domain
6317 names according to the rules of IDNA (internationalized domain names
6319 Since the IDNA code assumes that domain names are specified with the
6321 character set, an UTF-8 locale charset is required to represent all
6322 possible international domain names (before conversion, that is).
6326 \*(BO Ignore interrupt signals from the terminal while entering
6327 messages; instead echo them as
6329 characters and discard the current line.
6333 \*(BO Ignore end-of-file conditions
6334 .Pf ( Ql control-D )
6335 in compose mode on message input and in interactive command input.
6336 If set an interactive command input session can only be left by
6337 explicitly using one of the commands
6341 and message input in compose mode can only be terminated by entering
6344 on a line by itself or by using the
6346 .Sx "TILDE ESCAPES" ;
6348 overrides a setting of
6360 option for indenting messages,
6361 in place of the normal tabulator character
6363 which is the default.
6364 Be sure to quote the value if it contains spaces or tabs.
6368 \*(BO If set, an empty mailbox file is not removed.
6369 This may improve the interoperability with other mail user agents
6370 when using a common folder directory, and prevents malicious users
6371 from creating fake mailboxes in a world-writable spool directory.
6372 Note this only applies to local regular (MBOX) files, other mailbox
6373 types will never be removed.
6376 .It Va keep-content-length
6377 \*(BO When (editing messages and) writing
6379 mailbox files \*(UA can be told to keep the
6383 header fields that some MUAs generate by setting this variable.
6384 Since \*(UA does neither use nor update these non-standardized header
6385 fields (which in itself shows one of their conceptual problems),
6386 stripping them should increase interoperability in between MUAs that
6387 work with with same mailbox files.
6388 Note that, if this is not set but
6389 .Va writebackedited ,
6390 as below, is, a possibly performed automatic stripping of these header
6391 fields already marks the message as being modified.
6395 \*(BO When a message is saved it is usually discarded from the
6396 originating folder when \*(UA is quit.
6397 Setting this option causes all saved message to be retained.
6400 .It Va line-editor-disable
6401 \*(BO Turn off any enhanced line editing capabilities (see
6402 .Sx "On terminal control and line editor"
6407 \*(BO When a message is replied to and this variable is set,
6408 it is marked as having been answered.
6409 This mark has no technical meaning in the mail system;
6410 it just causes messages to be marked in the header summary,
6411 and makes them specially addressable.
6415 \*(BO \*(UA generates and expects RFC 4155 compliant MBOX text
6417 (With the restriction that RFC 4155 defines seven-bit clean data
6418 storage, but which can be overwritten by a contrary setting of
6420 Messages which are fetched over the network or from within already
6421 existing Maildir (or any non-MBOX) mailboxes may require so-called
6423 quoting (insertion of additional
6425 characters to prevent line content misinterpretation) to be applied in
6426 order to be storable in MBOX mailboxes, however, dependent on the
6427 circumspection of the message producer.
6428 E.g., \*(UA itself will, when newly generating messages, choose a
6429 .Pf Content-Transfer- Va encoding
6430 that prevents the necessity for such quoting \(en a necessary
6431 precondition to ensure message checksums won't change.
6433 By default \*(UA will perform this
6435 quoting in a way that results in a MBOX file that is compatible with
6436 the POSIX MBOX layout, which means that, in order not to exceed the
6437 capabilities of simple applications, many more
6439 lines get quoted (thus modified) than necessary according to RFC 4155.
6440 Set this option to instead generate MBOX files which comply to RFC 4155.
6444 \*(BO Internal development variable.
6447 .It Va message-id-disable
6448 \*(BO By setting this option the generation of
6450 can be completely suppressed, effectively leaving this task up to the
6451 mail-transfer-agent (MTA) or the SMTP server.
6452 (According to RFC 5321 your SMTP server is not required to add this
6453 field by itself, so you should ensure that it accepts messages without a
6457 .It Va message-inject-head
6458 A string to put at the beginning of each new message.
6459 The escape sequences tabulator
6466 .It Va message-inject-tail
6467 A string to put at the end of each new message.
6468 The escape sequences tabulator
6476 \*(BO Usually, when an
6478 expansion contains the sender, the sender is removed from the expansion.
6479 Setting this option suppresses these removals.
6484 option to be passed to mail-transfer-agents (MTAs);
6485 though most of the modern MTAs don't (no longer) document this flag, no
6486 MTA is known which doesn't support it (for historical compatibility).
6489 .It Va mime-allow-text-controls
6490 \*(BO When sending messages, each part of the message is MIME-inspected
6491 in order to classify the
6494 .Ql Content-Transfer-Encoding:
6497 that is required to send this part over mail transport, i.e.,
6498 a computation rather similar to what the
6500 command produces when used with the
6504 This classification however treats text files which are encoded in
6505 UTF-16 (seen for HTML files) and similar character sets as binary
6506 octet-streams, forcefully changing any
6511 .Ql application/octet-stream :
6512 If that actually happens a yet unset charset MIME parameter is set to
6514 effectively making it impossible for the receiving MUA to automatically
6515 interpret the contents of the part.
6517 If this option is set, and the data was unambiguously identified as text
6518 data at first glance (by a
6522 file extension), then the original
6524 will not be overwritten.
6527 .It Va mime-alternative-favour-rich
6528 \*(BO If this variable is set then rich MIME alternative parts (e.g.,
6529 HTML) will be preferred in favour of included plain text versions when
6530 displaying messages, provided that a handler exists which produces
6531 output that can be (re)integrated into \*(UA's normal visual display.
6532 (E.g., at the time of this writing some newsletters ship their full
6533 content only in the rich HTML part, whereas the plain text part only
6534 contains topic subjects.)
6537 .It Va mime-counter-evidence
6540 field is used to decide how to handle MIME parts.
6541 Some MUAs however don't use
6543 or a similar mechanism to correctly classify content, but simply specify
6544 .Ql application/octet-stream ,
6545 even for plain text attachments like
6547 If this variable is set then \*(UA will try to classify such MIME
6548 message parts on its own, if possible, for example via a possibly
6549 existent attachment filename.
6550 A non-empty value may also be given, in which case a number is expected,
6551 actually a carrier of bits.
6552 Creating the bit-carrying number is a simple addition:
6553 .Bd -literal -offset indent
6554 ? !echo Value should be set to $((2 + 4 + 8))
6555 Value should be set to 14
6558 .Bl -bullet -compact
6560 If bit two is set (2) then the detected
6562 content-type will be carried along with the message and be used for
6564 .Va pipe-TYPE/SUBTYPE
6565 is responsible for the MIME part, shall that question arise;
6566 when displaying such a MIME part the part-info will indicate the
6567 overridden content-type by showing a plus-sign
6570 If bit three is set (4) then the counter-evidence is always produced
6571 and a positive result will be used as the MIME type, even forcefully
6572 overriding the parts given MIME type.
6574 If bit four is set (8) then as a last resort the actual content of
6575 .Ql application/octet-stream
6576 parts will be inspected, so that data which looks like plain text can be
6581 .It Va mimetypes-load-control
6582 This option can be used to control which of the
6584 databases are loaded by \*(UA, as furtherly described in the section
6585 .Sx "The mime.types files" .
6588 is part of the option value, then the user's personal
6590 file will be loaded (if it exists); likewise the letter
6592 controls loading of the system wide
6593 .Pa /etc/mime.types ;
6594 directives found in the user file take precedence, letter matching is
6596 If this option is not set \*(UA will try to load both files.
6597 Incorporation of the \*(UA-builtin MIME types cannot be suppressed,
6598 but they will be matched last.
6600 More sources can be specified by using a different syntax: if the
6601 value string contains an equals sign
6603 then it is instead parsed as a comma-separated list of the described
6606 pairs; the given filenames will be expanded and loaded, and their
6607 content may use the extended syntax that is described in the section
6608 .Sx "The mime.types files" .
6609 Directives found in such files always take precedence (are prepended to
6610 the MIME type cache).
6613 .It Va NAIL_EXTRA_RC
6614 The name of an optional startup file to be read last.
6615 This variable has an effect only if it is set in any of the
6616 .Sx "Resource files" ,
6617 it is not imported from the environment.
6618 Use this file for commands that are not understood by other POSIX
6623 .It Va netrc-lookup-USER@HOST , netrc-lookup-HOST , netrc-lookup
6624 \*(BO\*(IN\*(OP Used to control usage of the users
6626 file for lookup of account credentials, as documented in the section
6627 .Sx "On URL syntax and credential lookup"
6631 .Sx "The .netrc file"
6632 documents the file format.
6644 then \*(UA will read the output of a shell pipe instead of the users
6646 file if this variable is set (to the desired shell command).
6647 This can be used to, e.g., store
6651 .Dl set netrc-pipe='gpg -qd ~/.netrc.pgp'
6655 If this variable has the value
6657 newly created local folders will be in Maildir format.
6661 Checks for new mail in the current folder each time the prompt is shown.
6662 A Maildir folder must be re-scanned to determine if new mail has arrived.
6663 If this variable is set to the special value
6665 then a Maildir folder will not be rescanned completely, but only
6666 timestamp changes are detected.
6670 .It Va on-compose-enter , on-compose-leave
6671 \*(ID Macro hooks which will be executed before compose mode is
6672 entered, and after composing has been finished, respectively.
6673 Please note that this interface is very likely to change in v15, and
6674 should therefore possibly even be seen as experimental.
6676 are by default enabled for these hooks, causing any setting to be
6677 forgotten after the message has been sent.
6678 The following variables will be set temporarily during execution of the
6681 .Bl -tag -compact -width ".It Va compose_subject"
6684 .It Va compose-sender
6686 .It Va compose-to , compose-cc , compose-bcc
6687 The list of receiver addresses as a space-separated list.
6688 .It Va compose-subject
6694 \*(BO Causes the filename given in the
6697 and the sender-based filenames for the
6701 commands to be interpreted relative to the directory given in the
6703 variable rather than to the current directory,
6704 unless it is set to an absolute pathname.
6708 \*(BO If set, each message feed through the command given for
6710 is followed by a formfeed character
6714 .It Va password-USER@HOST , password-HOST , password
6715 \*(IN Variable chain that sets a password, which is used in case none has
6716 been given in the protocol and account-specific URL;
6717 as a last resort \*(UA will ask for a password on the user's terminal if
6718 the authentication method requires a password.
6719 Specifying passwords in a startup file is generally a security risk;
6720 the file should be readable by the invoking user only.
6722 .It Va password-USER@HOST
6723 \*(OU (see the chain above for \*(IN)
6724 Set the password for
6728 If no such variable is defined for a host,
6729 the user will be asked for a password on standard input.
6730 Specifying passwords in a startup file is generally a security risk;
6731 the file should be readable by the invoking user only.
6735 \*(BO Send messages to the
6737 command without performing MIME and character set conversions.
6741 .It Va pipe-TYPE/SUBTYPE
6742 When a MIME message part of type
6744 (case-insensitive) is displayed or quoted,
6745 its text is filtered through the value of this variable interpreted as
6749 forces interpretation of the message part as plain text, e.g.,
6750 .Ql set pipe-application/xml=@
6751 will henceforth display XML
6753 (The same could also be achieved by adding a MIME type marker with the
6756 And \*(OPally MIME type handlers may be defined via
6757 .Sx "The Mailcap files"
6758 \(em corresponding flag strings are shown in parenthesis below.)
6763 can in fact be used to adjust usage and behaviour of a following shell
6764 command specification by appending trigger characters to it, e.g., the
6765 following hypothetical command specification could be used:
6766 .Bd -literal -offset indent
6767 set pipe-X/Y='@*!++=@vim ${NAIL_FILENAME_TEMPORARY}'
6771 .Bl -tag -compact -width ".It Ql __"
6773 Simply by using the special
6775 prefix the MIME type (shell command) handler will only be invoked to
6776 display or convert the MIME part if the message is addressed directly
6777 and alone by itself.
6778 Use this trigger to disable this and always invoke the handler
6779 .Pf ( Cd x-mailx-always ) .
6782 If set the handler will not be invoked when a message is to be quoted,
6783 but only when it will be displayed
6784 .Pf ( Cd x-mailx-noquote ) .
6787 The command will be run asynchronously, i.e., without blocking \*(UA,
6788 which may be a handy way to display a, e.g., PDF file while also
6789 continuing to read the mail message
6790 .Pf ( Cd x-mailx-async ) .
6791 Asynchronous execution implies
6795 The command must be run on an interactive terminal, \*(UA will
6796 temporarily release the terminal to it
6797 .Pf ( Cd needsterminal ) .
6798 This flag is mutual exclusive with
6800 will only be used in interactive mode and implies
6804 Request creation of a zero-sized temporary file, the absolute pathname
6805 of which will be made accessible via the environment variable
6806 .Ev NAIL_FILENAME_TEMPORARY
6807 .Pf ( Cd x-mailx-tmpfile ) .
6808 If this trigger is given twice then the file will be unlinked
6809 automatically by \*(UA when the command loop is entered again at latest
6810 .Pf ( Cd x-mailx-tmpfile-unlink ) .
6811 (Don't use this for asynchronous handlers.)
6814 Normally the MIME part content is passed to the handler via standard
6815 input; if this flag is set then the data will instead be written into
6816 .Ev NAIL_FILENAME_TEMPORARY
6817 .Pf ( Cd x-mailx-tmpfile-fill ) ,
6818 the creation of which is implied; note however that in order to cause
6819 deletion of the temporary file you still have to use two plus signs
6824 To avoid ambiguities with normal shell command content you can use
6825 another at-sign to forcefully terminate interpretation of remaining
6827 (Any character not in this list will have the same effect.)
6831 Some information about the MIME part to be displayed is embedded into
6832 the environment of the shell command:
6835 .Bl -tag -compact -width ".It Ev _AIL__ILENAME__ENERATED"
6838 The MIME content-type of the part, if known, the empty string otherwise.
6841 .It Ev NAIL_CONTENT_EVIDENCE
6843 .Va mime-counter-evidence
6844 includes the carry-around-bit (2), then this will be set to the detected
6845 MIME content-type; not only then identical to
6846 .Ev \&\&NAIL_CONTENT
6850 .It Ev NAIL_FILENAME
6851 The filename, if any is set, the empty string otherwise.
6854 .It Ev NAIL_FILENAME_GENERATED
6858 .It Ev NAIL_FILENAME_TEMPORARY
6859 If temporary file creation has been requested through the command prefix
6860 this variable will be set and contain the absolute pathname of the
6865 The temporary directory that \*(UA uses.
6866 Usually identical to
6868 but guaranteed to be set and usable by child processes;
6869 to ensure the latter condition for
6876 .It Va pipe-EXTENSION
6877 This is identical to
6878 .Va pipe-TYPE/SUBTYPE
6881 (normalized to lowercase using character mappings of the ASCII charset)
6882 names a file extension, e.g.,
6884 Handlers registered using this method take precedence.
6887 .It Va pop3-auth-USER@HOST , pop3-auth-HOST , pop3-auth
6888 \*(OP\*(IN Variable chain that sets the POP3 authentication method.
6889 The only possible value as of now is
6891 which is thus the default.
6894 .Mx Va pop3-bulk-load
6895 .It Va pop3-bulk-load-USER@HOST , pop3-bulk-load-HOST , pop3-bulk-load
6896 \*(BO\*(OP When accessing a POP3 server \*(UA loads the headers of
6897 the messages, and only requests the message bodies on user request.
6898 For the POP3 protocol this means that the message headers will be
6900 If this option is set then \*(UA will download only complete messages
6901 from the given POP3 server(s) instead.
6903 .Mx Va pop3-keepalive
6904 .It Va pop3-keepalive-USER@HOST , pop3-keepalive-HOST , pop3-keepalive
6905 \*(OP POP3 servers close the connection after a period of inactivity;
6906 the standard requires this to be at least 10 minutes,
6907 but practical experience may vary.
6908 Setting this variable to a numeric value greater than
6912 command to be sent each value seconds if no other operation is performed.
6915 .It Va pop3-no-apop-USER@HOST , pop3-no-apop-HOST , pop3-no-apop
6916 \*(BO\*(OP Unless this variable is set the
6918 authentication method will be used when connecting to a POP3 server that
6922 is that the password is not sent in clear text over the wire and that
6923 only a single packet is sent for the user/password tuple.
6925 .Va pop3-no-apop-HOST
6928 .Mx Va pop3-use-starttls
6929 .It Va pop3-use-starttls-USER@HOST , pop3-use-starttls-HOST , pop3-use-starttls
6930 \*(BO\*(OP Causes \*(UA to issue a
6932 command to make an unencrypted POP3 session SSL/TLS encrypted.
6933 This functionality is not supported by all servers,
6934 and is not used if the session is already encrypted by the POP3S method.
6936 .Va pop3-use-starttls-HOST
6940 .It Va print-alternatives
6941 \*(BO When a MIME message part of type
6942 .Ql multipart/alternative
6943 is displayed and it contains a subpart of type
6945 other parts are normally discarded.
6946 Setting this variable causes all subparts to be displayed,
6947 just as if the surrounding part was of type
6948 .Ql multipart/mixed .
6952 The string shown when a command is accepted.
6953 Prompting may be prevented by setting this to the null string
6955 .Pf no Va prompt ) .
6956 If a value is assigned the following \*(UA specific additional sequences
6963 is set, in which case it expands to
6967 is the default value of
6970 which will expand to
6972 if the last command failed and to
6976 which will expand to the name of the currently active
6978 if any, and to the empty string otherwise, and
6980 which will expand to the name of the currently active mailbox.
6981 (Note that the prompt buffer is size-limited, excess is cut off.)
6987 to encapsulate the expansions of the
6991 escape sequences as necessary to correctly display bidirectional text,
6992 this is not true for the final string that makes up
6994 as such, i.e., real BIDI handling is not supported.
6998 \*(BO Suppresses the printing of the version when first invoked.
7002 If set, \*(UA starts a replying message with the original message
7003 prefixed by the value of the variable
7005 Normally, a heading consisting of
7006 .Dq Fromheaderfield wrote:
7007 is put before the quotation.
7012 variable, this heading is omitted.
7015 is assigned, the headers selected by the
7016 .Ic ignore Ns / Ns Ic retain
7017 commands are put above the message body,
7020 acts like an automatic
7026 is assigned, all headers are put above the message body and all MIME
7027 parts are included, making
7029 act like an automatic
7032 .Va quote-as-attachment .
7035 .It Va quote-as-attachment
7036 \*(BO Add the original message in its entirety as a
7038 MIME attachment when replying to a message.
7039 Note this works regardless of the setting of
7044 \*(OP Can be set in addition to
7046 Setting this turns on a more fancy quotation algorithm in that leading
7047 quotation characters are compressed and overlong lines are folded.
7049 can be set to either one or two (space separated) numeric values,
7050 which are interpreted as the maximum (goal) and the minimum line length,
7051 respectively, in a spirit rather equal to the
7053 program, but line-, not paragraph-based.
7054 If not set explicitly the minimum will reflect the goal algorithmically.
7055 The goal can't be smaller than the length of
7057 plus some additional pad.
7058 Necessary adjustments take place silently.
7061 .It Va recipients-in-cc
7062 \*(BO On group replies, specify only the sender of the original mail in
7064 and mention the other recipients in the secondary
7066 By default all recipients of the original mail will be addressed via
7071 If defined, gives the pathname of the folder used to record all outgoing
7073 If not defined, then outgoing mail is not saved.
7074 When saving to this folder fails the message is not sent,
7075 but instead saved to
7079 .It Va record-resent
7080 \*(BO If both this variable and the
7087 commands save messages to the
7089 folder as it is normally only done for newly composed messages.
7092 .It Va reply-in-same-charset
7093 \*(BO If this variable is set \*(UA first tries to use the same
7094 character set of the original message for replies.
7095 If this fails, the mechanism described in
7096 .Sx "Character sets"
7097 is evaluated as usual.
7100 .It Va reply_strings
7101 Can be set to a comma-separated list of (case-insensitive according to
7102 ASCII rules) strings which shall be recognized in addition to the
7105 reply message indicators \(en builtin are
7107 which is mandated by RFC 5322, as well as the german
7112 A list of addresses to put into the
7114 field of the message header.
7115 Members of this list are handled as if they were in the
7120 .It Va reply-to-honour
7123 header is honoured when replying to a message via
7127 This is a quadoption; if set without a value it defaults to
7131 .It Va rfc822-body-from_
7132 \*(BO This variable can be used to force displaying a so-called
7134 line for messages that are embedded into an envelope mail via the
7136 MIME mechanism, for more visual convenience.
7140 \*(BO Enable saving of (partial) messages in
7142 upon interrupt or delivery error.
7146 When \*(UA initially displays the message headers it determines the
7147 number to display by looking at the speed of the terminal.
7148 The faster the terminal, the more will be shown.
7149 This option specifies the number to use and overrides the calculation.
7150 This number is also used for scrolling with the
7153 Overall screen dimensions and pager usage is influenced by the
7154 environment variables
7162 .It Va searchheaders
7163 \*(BO Expand message-list specifiers in the form
7165 to all messages containing the substring
7169 The string search is case insensitive.
7173 \*(OP A comma-separated list of character set names that can be used in
7174 outgoing internet mail.
7175 The value of the variable
7177 is automatically appended to this list of character-sets.
7178 If no character set conversion capabilities are compiled into \*(UA then
7179 the only supported charset is
7182 .Va sendcharsets-else-ttycharset
7183 and refer to the section
7184 .Sx "Character sets"
7185 for the complete picture of character set conversion in \*(UA.
7188 .It Va sendcharsets-else-ttycharset
7189 \*(BO\*(OP If this variable is set, but
7191 is not, then \*(UA acts as if
7193 had been set to the value of the variable
7195 In effect this combination passes through the message data in the
7196 character set of the current locale (given that
7198 hasn't been set manually), i.e., without converting it to the
7200 fallback character set.
7201 Thus, mail message text will be in ISO-8859-1 encoding when send from
7202 within a ISO-8859-1 locale, and in UTF-8 encoding when send from within
7204 If no character set conversion capabilities are available in \*(UA then
7205 the only supported character set is
7210 An address that is put into the
7212 field of outgoing messages, quoting RFC 5322: the mailbox of the agent
7213 responsible for the actual transmission of the message.
7214 This field should normally not be used unless the
7216 field contains more than one address, on which case it is required.
7219 address is handled as if it were in the
7225 To use an alternate mail transport agent (MTA),
7226 set this option to the full pathname of the program to use.
7227 It may be necessary to set
7228 .Va sendmail-progname
7231 The MTA will be passed command line arguments from several possible
7232 sources: from the variable
7233 .Va sendmail-arguments
7234 if set, from the command line if given and the variable
7237 Argument processing of the MTA will be terminated with a
7241 The otherwise occurring implicit usage of the following MTA command line
7242 arguments can be disabled by setting the boolean option
7243 .Va sendmail-no-default-arguments
7244 (which will also disable passing
7248 (for not treating a line with only a dot
7250 character as the end of input),
7258 option is set); in conjunction with the
7260 command line option \*(UA will also pass
7266 .It Va sendmail-arguments
7267 Arguments to pass through to the Mail-Transfer-Agent can be given via
7269 The content of this variable will be split up in a vector of arguments
7270 which will be joined onto other possible MTA options:
7272 .Dl set sendmail-arguments='-t -X \&"/tmp/my log\&"'
7275 .It Va sendmail-no-default-arguments
7276 \*(BO Unless this option is set \*(UA will pass some well known
7277 standard command line options to the defined
7279 program, see there for more.
7282 .It Va sendmail-progname
7283 Many systems use a so-called
7285 environment to ensure compatibility with
7287 This works by inspecting the name that was used to invoke the mail
7289 If this variable is set then the mailwrapper (the program that is
7290 actually executed when calling
7292 will treat its contents as that name.
7298 \*(BO When sending a message wait until the MTA (including the builtin
7299 SMTP one) exits before accepting further commands.
7301 with this variable set errors reported by the MTA will be recognizable!
7302 If the MTA returns a non-zero exit status,
7303 the exit status of \*(UA will also be non-zero.
7307 \*(BO Setting this option causes \*(UA to start at the last message
7308 instead of the first one when opening a mail folder.
7312 \*(BO Causes \*(UA to use the sender's real name instead of the plain
7313 address in the header field summary and in message specifications.
7317 \*(BO Causes the recipient of the message to be shown in the header
7318 summary if the message was sent by the user.
7322 A string for use with the
7328 A string for use with the
7334 Must correspond to the name of a readable file if set.
7335 The file's content is then appended to each singlepart message
7336 and to the first part of each multipart message.
7337 Be warned that there is no possibility to edit the signature for an
7341 .It Va skipemptybody
7342 \*(BO If an outgoing message does not contain any text in its first or
7343 only message part, do not send it but discard it silently (see also the
7349 \*(OP Specifies a directory with CA certificates in PEM (Privacy
7350 Enhanced Mail) format for verification of S/MIME signed messages.
7353 .It Va smime-ca-file
7354 \*(OP Specifies a file with CA certificates in PEM format for
7355 verification of S/MIME signed messages.
7358 .It Va smime-cipher-USER@HOST , smime-cipher
7359 \*(OP Specifies the cipher to use when generating S/MIME encrypted
7360 messages (for the specified account).
7361 RFC 5751 mandates a default of
7364 Possible values are (case-insensitive and) in decreasing cipher strength:
7372 (DES EDE3 CBC, 168 bits; default if
7374 isn't available) and
7378 The actually available cipher algorithms depend on the cryptographic
7379 library that \*(UA uses.
7380 \*(OP Support for more cipher algorithms may be available through
7381 dynamic loading via, e.g.,
7382 .Xr EVP_get_cipherbyname 3
7383 (OpenSSL) if \*(UA has been compiled to support this.
7386 .It Va smime-crl-dir
7387 \*(OP Specifies a directory that contains files with CRLs in PEM format
7388 to use when verifying S/MIME messages.
7391 .It Va smime-crl-file
7392 \*(OP Specifies a file that contains a CRL in PEM format to use when
7393 verifying S/MIME messages.
7396 .It Va smime-encrypt-USER@HOST
7397 \*(OP If this variable is set, messages send to the given receiver are
7398 encrypted before sending.
7399 The value of the variable must be set to the name of a file that
7400 contains a certificate in PEM format.
7402 If a message is sent to multiple recipients,
7403 each of them for whom a corresponding variable is set will receive an
7404 individually encrypted message;
7405 other recipients will continue to receive the message in plain text
7407 .Va smime-force-encryption
7409 It is recommended to sign encrypted messages, i.e., to also set the
7414 .It Va smime-force-encryption
7415 \*(BO\*(OP Causes \*(UA to refuse sending unencrypted messages.
7418 .It Va smime-no-default-ca
7419 \*(BO\*(OP Don't load default CA locations when verifying S/MIME signed
7424 \*(BO\*(OP S/MIME sign outgoing messages with the user's private key
7425 and include the user's certificate as a MIME attachment.
7426 Signing a message enables a recipient to verify that the sender used
7427 a valid certificate,
7428 that the email addresses in the certificate match those in the message
7429 header and that the message content has not been altered.
7430 It does not change the message text,
7431 and people will be able to read the message as usual.
7433 .Va smime-sign-cert , smime-sign-include-certs
7435 .Va smime-sign-message-digest .
7437 .Mx Va smime-sign-cert
7438 .It Va smime-sign-cert-USER@HOST , smime-sign-cert
7439 \*(OP Points to a file in PEM format.
7440 For the purpose of signing and decryption this file needs to contain the
7441 user's private key as well as his certificate.
7445 is always derived from the value of
7447 (or, if that contains multiple addresses,
7449 For the purpose of encryption the recipient's public encryption key
7450 (certificate) is expected; the command
7452 can be used to save certificates of signed messages (the section
7453 .Sx "Signed and encrypted messages with S/MIME"
7454 gives some details).
7455 This mode of operation is usually driven by the specialized form.
7457 When decrypting messages the account is derived from the recipient
7462 of the message, which are searched for addresses for which such
7464 \*(UA always uses the first address that matches,
7465 so if the same message is sent to more than one of the user's addresses
7466 using different encryption keys, decryption might fail.
7468 .Mx Va smime-sign-include-certs
7469 .It Va smime-sign-include-certs-USER@HOST , smime-sign-include-certs
7470 \*(OP If used, this is supposed to a consist of a comma-separated list
7471 of files, each of which containing a single certificate in PEM format to
7472 be included in the S/MIME message in addition to the
7475 This is most useful for long certificate chains if it is desired to aid
7476 the receiving party's verification process.
7477 Note that top level certificates may also be included in the chain but
7478 don't play a role for verification.
7480 .Va smime-sign-cert .
7481 Remember that for this
7483 refers to the variable
7485 (or, if that contains multiple addresses,
7488 .Mx Va smime-sign-message-digest
7489 .It Va smime-sign-message-digest-USER@HOST , smime-sign-message-digest
7490 \*(OP Specifies the message digest to use when signing S/MIME messages.
7491 RFC 5751 mandates a default of
7493 Possible values are (case-insensitive and) in decreasing cipher strength:
7501 The actually available message digest algorithms depend on the
7502 cryptographic library that \*(UA uses.
7503 \*(OP Support for more message digest algorithms may be available
7504 through dynamic loading via, e.g.,
7505 .Xr EVP_get_digestbyname 3
7506 (OpenSSL) if \*(UA has been compiled to support this.
7507 Remember that for this
7509 refers to the variable
7511 (or, if that contains multiple addresses,
7517 \*(OP Normally \*(UA invokes the program defined via
7519 to transfer messages, as described in
7520 .Sx "On sending mail, and non-interactive mode" .
7523 variable will instead cause SMTP network connections be made to the
7524 server specified therein in order to directly submit the message.
7525 \*(UA knows about three different
7526 .Dq SMTP protocols :
7528 .Bl -bullet -compact
7530 The plain SMTP protocol (RFC 5321) that normally lives on the
7531 server port 25 and requires setting the
7532 .Va smtp-use-starttls
7533 variable to enter a SSL/TLS encrypted session state.
7534 Assign a value like \*(IN
7535 .Ql [smtp://][user[:password]@]server[:port]
7537 .Ql [smtp://]server[:port] )
7538 to choose this protocol.
7540 Then the so-called SMTPS which is supposed to live on server port 465
7541 and is automatically SSL/TLS secured.
7542 Unfortunately it never became a standardized protocol and may thus not
7543 be supported by your hosts network service database
7544 \(en in fact the port number has already been reassigned to other
7547 SMTPS is nonetheless a commonly offered protocol and thus can be
7548 chosen by assigning a value like \*(IN
7549 .Ql smtps://[user[:password]@]server[:port]
7551 .Ql smtps://server[:port] ) ;
7552 due to the mentioned problems it is usually necessary to explicitly
7557 Finally there is the SUBMISSION protocol (RFC 6409), which usually
7558 lives on server port 587 and is practically identically to the SMTP
7559 protocol from \*(UA's point of view beside that; it requires setting the
7560 .Va smtp-use-starttls
7561 variable to enter a SSL/TLS secured session state.
7562 Assign a value like \*(IN
7563 .Ql submission://[user[:password]@]server[:port]
7565 .Ql submission://server[:port] ) .
7568 For more on credentials etc., please see
7569 .Sx "On URL syntax and credential lookup" .
7570 The SMTP transfer is executed in a child process, which runs
7571 asynchronously unless either the
7576 If it receives a TERM signal, it will abort and save the message to
7581 .It Va smtp-auth-USER@HOST , smtp-auth-HOST , smtp-auth
7582 \*(OP Variable chain that sets the SMTP authentication method.
7589 as well as the \*(OPal methods
7595 method doesn't need any user credentials,
7597 requires a user name and all other methods require a user name and
7605 .Va smtp-auth-password
7607 .Va smtp-auth-user ) .
7612 .Va smtp-auth-USER@HOST :
7613 may override dependent on sender address in the variable
7616 .It Va smtp-auth-password
7617 \*(OP\*(OU Sets the global fallback password for SMTP authentication.
7618 If the authentication method requires a password, but neither
7619 .Va smtp-auth-password
7621 .Va smtp-auth-password-USER@HOST
7623 \*(UA will ask for a password on the user's terminal.
7625 .It Va smtp-auth-password-USER@HOST
7627 .Va smtp-auth-password
7628 for specific values of sender addresses, dependent upon the variable
7631 .It Va smtp-auth-user
7632 \*(OP\*(OU Sets the global fallback user name for SMTP authentication.
7633 If the authentication method requires a user name, but neither
7636 .Va smtp-auth-user-USER@HOST
7638 \*(UA will ask for a user name on the user's terminal.
7640 .It Va smtp-auth-user-USER@HOST
7643 for specific values of sender addresses, dependent upon the variable
7647 .It Va smtp-hostname
7648 \*(IN Normally \*(UA uses the variable
7650 to derive the necessary
7652 information to issue a
7657 can be used to use the
7659 from the SMTP account
7666 from the content of this variable (or, if that is the empty string,
7668 or the local hostname as a last resort).
7669 This often allows using an address that is itself valid but hosted by
7670 a provider other than which (in
7672 is about to send the message.
7673 Setting this variable also influences the generated
7676 .Mx Va smtp-use-starttls
7677 .It Va smtp-use-starttls-USER@HOST , smtp-use-starttls-HOST , smtp-use-starttls
7678 \*(BO\*(OP Causes \*(UA to issue a
7680 command to make an SMTP session SSL/TLS encrypted, i.e., to enable
7681 transport layer security.
7685 .It Va spam-interface
7686 \*(OP In order to use any of the spam-related commands (like, e.g.,
7688 the desired spam interface must be defined by setting this variable.
7689 Please refer to the manual section
7691 for the complete picture of spam handling in \*(UA.
7692 All or none of the following interfaces may be available:
7694 .Bl -tag -width ".It Ql _ilte_"
7700 .Pf ( Lk http://spamassassin.apache.org SpamAssassin )
7702 Different to the generic filter interface \*(UA will automatically add
7703 the correct arguments for a given command and has the necessary
7704 knowledge to parse the program's output.
7707 will have been compiled into the \*(UA binary if
7712 Shall it be necessary to define a specific connection type (rather than
7713 using a configuration file for that), the variable
7715 can be used as in, e.g.,
7716 .Ql -d server.example.com -p 783 .
7717 It is also possible to specify a per-user configuration via
7719 Note that this interface doesn't inspect the
7721 flag of a message for the command
7725 \*(UA will directly communicate with the
7731 stream socket as specified in
7733 It is possible to specify a per-user configuration via
7737 generic spam filter support via freely configurable hooks.
7738 This interface is meant for programs like
7740 and requires according behaviour in respect to the hooks' exit
7741 status for at least the command
7744 meaning a message is spam,
7748 for unsure and any other return value indicating a hard error);
7749 since the hooks can include shell code snippets diverting behaviour
7750 can be intercepted as necessary.
7752 .Va spamfilter-ham , spamfilter-noham , spamfilter-nospam , \
7755 .Va spamfilter-spam ;
7758 contains examples for some programs.
7759 The process environment of the hooks will have the variables
7760 .Ev NAIL_TMPDIR , TMPDIR
7762 .Ev NAIL_FILENAME_GENERATED
7764 Note that spam score support for
7766 isn't supported unless the \*(OPtional regular expression support is
7768 .Va spamfilter-rate-scanscore
7775 \*(OP Messages that exceed this size won't be passed through to the
7777 .Va spam-interface .
7778 If unset or 0, the default of 420000 bytes is used.
7781 .It Va spamc-command
7782 \*(OP The path to the
7786 .Va spam-interface .
7787 Note that the path is not expanded, but used
7789 A fallback path will have been compiled into the \*(UA binary if the
7790 executable had been found during compilation.
7793 .It Va spamc-arguments
7794 \*(OP Even though \*(UA deals with most arguments for the
7797 automatically, it may at least sometimes be desirable to specify
7798 connection-related ones via this variable, e.g.,
7799 .Ql -d server.example.com -p 783 .
7803 \*(OP Specify a username for per-user configuration files for the
7805 .Va spam-interface .
7806 If this is set to the empty string then \*(UA will use the name of the
7812 \*(OP Specify the path of the
7814 domain socket on which
7816 listens for connections for the
7818 .Va spam-interface .
7819 Note that the path is not expanded, but used
7824 \*(OP Specify a username for per-user configuration files for the
7826 .Va spam-interface .
7827 If this is set to the empty string then \*(UA will use the name of the
7836 .It Va spamfilter-ham , spamfilter-noham , \
7837 spamfilter-nospam , spamfilter-rate , spamfilter-spam
7838 \*(OP Command and argument hooks for the
7840 .Va spam-interface .
7843 contains examples for some programs.
7846 .It Va spamfilter-rate-scanscore
7847 \*(OP Because of the generic nature of the
7850 spam scores are not supported for it by default, but if the \*(OPtional
7851 regular expression support is available then setting this variable can
7852 be used to overcome this restriction.
7853 It is interpreted as follows: first a number (digits) is parsed that
7854 must be followed by a semicolon
7856 and an extended regular expression.
7857 Then the latter is used to parse the first output line of the
7859 hook, and, in case the evaluation is successful, the group that has been
7860 specified via the number is interpreted as a floating point scan score.
7864 \*(OP Specifies a directory with CA certificates in PEM (Pricacy
7865 Enhanced Mail) for verification of of SSL/TLS server certificates.
7867 .Xr SSL_CTX_load_verify_locations 3
7868 for more information.
7872 \*(OP Specifies a file with CA certificates in PEM format for
7873 verification of SSL/TLS server certificates.
7875 .Xr SSL_CTX_load_verify_locations 3
7876 for more information.
7879 .It Va ssl-cert-USER@HOST , ssl-cert-HOST , ssl-cert
7880 \*(OP Variable chain that sets the file name for a SSL/TLS client
7881 certificate required by some servers.
7882 This is a direct interface to the
7886 function of the OpenSSL library, if available.
7888 .Mx Va ssl-cipher-list
7889 .It Va ssl-cipher-list-USER@HOST , ssl-cipher-list-HOST , ssl-cipher-list
7890 \*(OP Specifies a list of ciphers for SSL/TLS connections.
7891 This is a direct interface to the
7895 function of the OpenSSL library, if available; see
7897 for more information.
7898 By default \*(UA doesn't set a list of ciphers, which in effect will use a
7900 specific cipher (protocol standards ship with a list of acceptable
7901 ciphers), possibly cramped to what the actually used SSL/TLS library
7902 supports \(en the manual section
7903 .Sx "An example configuration"
7904 also contains a SSL/TLS use case.
7907 .It Va ssl-config-file
7908 \*(OP If this variable is set \*(UA will call
7909 .Xr CONF_modules_load_file 3
7910 to allow OpenSSL to be configured according to the host system wide
7912 If a non-empty value is given then this will be used to specify the
7913 configuration file to be used instead of the global OpenSSL default;
7914 note that in this case it is an error if the file cannot be loaded.
7915 The application name will always be passed as
7920 \*(OP Specifies a file that contains a CRL in PEM format to use when
7921 verifying SSL/TLS server certificates.
7925 \*(OP Specifies a directory that contains files with CRLs in PEM format
7926 to use when verifying SSL/TLS server certificates.
7929 .It Va ssl-key-USER@HOST , ssl-key-HOST , ssl-key
7930 \*(OP Variable chain that sets the file name for the private key of
7931 a SSL/TLS client certificate.
7932 If unset, the name of the certificate file is used.
7933 The file is expected to be in PEM format.
7934 This is a direct interface to the
7938 function of the OpenSSL library, if available.
7941 .It Va ssl-method-USER@HOST , ssl-method-HOST , ssl-method
7942 \*(OB\*(OP Please use the newer and more flexible
7944 instead: if both values are set,
7946 will take precedence!
7947 Can be set to the following values, the actually used
7949 specification to which it is mapped is shown in parenthesis:
7951 .Pf ( Ql -ALL, TLSv1.2 ) ,
7953 .Pf ( Ql -ALL, TLSv1.1 ) ,
7955 .Pf ( Ql -ALL, TLSv1 )
7958 .Pf ( Ql -ALL, SSLv3 ) ;
7963 and thus includes the SSLv3 protocol.
7964 Note that SSLv2 is no longer supported at all.
7967 .It Va ssl-no-default-ca
7968 \*(BO\*(OP Don't load default CA locations to verify SSL/TLS server
7972 .It Va ssl-protocol-USER@HOST , ssl-protocol-HOST , ssl-protocol
7973 \*(OP Specify the used SSL/TLS protocol.
7974 This is a direct interface to the
7978 function of the OpenSSL library, if available;
7979 otherwise an \*(UA internal parser is used which understands the
7980 following subset of (case-insensitive) command strings:
7986 as well as the special value
7988 Multiple specifications may be given via a comma-separated list which
7989 ignores any whitespace.
7992 plus prefix will enable a protocol, a
7994 minus prefix will disable it, so that
7996 will enable only the TLSv1.2 protocol.
7998 It depends upon the used TLS/SSL library which protocols are actually
7999 supported and which protocols are used if
8001 is not set, but note that SSLv2 is no longer supported at all and
8003 Especially for older protocols explicitly securing
8005 may be worthwile, see
8006 .Sx "An example configuration" .
8010 \*(OP Gives the pathname to an entropy daemon socket, see
8012 Not all SSL/TLS libraries support this.
8015 .It Va ssl-rand-file
8016 \*(OP Gives the filename to a file with random entropy data, see
8017 .Xr RAND_load_file 3 .
8018 If this variable is not set, or set to the empty string, or if the
8019 filename expansion failed, then
8020 .Xr RAND_file_name 3
8021 will be used to create the filename if, and only if,
8023 documents that the SSL PRNG is not yet sufficiently seeded.
8024 If \*(UA successfully seeded the SSL PRNG then it'll update the file via
8025 .Xr RAND_write_file 3 .
8026 This variable is only used if
8028 is not set (or not supported by the SSL/TLS library).
8031 .It Va ssl-verify-USER@HOST , ssl-verify-HOST , ssl-verify
8032 \*(OP Variable chain that sets the action to be performed if an error
8033 occurs during SSL/TLS server certificate validation.
8034 Valid (case-insensitive) values are
8036 (fail and close connection immediately),
8038 (ask whether to continue on standard input),
8040 (show a warning and continue),
8042 (do not perform validation).
8048 If only set without an assigned value, then this option inhibits the
8053 header fields that include obvious references to \*(UA.
8054 There are two pitfalls associated with this:
8055 First, the message id of outgoing messages is not known anymore.
8056 Second, an expert may still use the remaining information in the header
8057 to track down the originating mail user agent.
8062 suppression doesn't occur.
8067 (\*(OP) This specifies a comma-separated list of
8072 .Sx "On terminal control and line editor" ,
8073 escape commas with reverse solidus) to be used to overwrite or define
8075 Note that this variable will only be queried once at program startup and
8076 can thus only be specified in resource files or on the command line.
8079 String capabilities form
8081 pairs and are expected unless noted otherwise.
8082 Numerics have to be notated as
8084 where the number is expected in normal decimal notation.
8085 Finally, booleans don't have any value but indicate a true or false
8086 state simply by being defined or not; this indeed means that \*(UA
8087 doesn't support undefining a boolean that normally exists.
8088 The following example defines that the terminal has 256 colours:
8090 .Bd -literal -offset indent
8091 set termcap="colors=256"
8095 Keycodes can easily be detected with the command
8097 by running it on an interactive terminal via
8101 command line option if available) and pressing some keys: here
8109 (actually a visualized numeric where
8111 stands for 1 etc.; in fact: the numeric value of
8113 in the US-ASCII character set bitwise XORd with
8116 .Ql $ echo $((0x41 ^ 0x40)) .
8119 and other control characters have to be notated as shell-style
8120 escape sequences, e.g.,
8130 The following terminal capabilities are or may be meaningful for the
8131 operation of the builtin line editor or \*(UA in general:
8134 .Bl -tag -compact -width yay
8136 .It Cd colors Ns \0or Cd Co
8138 numeric capability specifying the maximum number of colours.
8139 Note that \*(UA doesn't actually care about the terminal beside that,
8140 but always emits ANSI/ISO 6429 escape sequences for producing the
8141 colour and font attributes.
8144 .It Cd rmcup Ns \0or Cd te Ns \0/ Cd smcup Ns \0or Cd ti
8148 respectively: exit and enter the alternative screen
8150 effectively turning \*(UA into a fullscreen application.
8151 To disable that, set (at least) one to the empty string.
8153 .It Cd smkx Ns \0or Cd ks Ns \0/ Cd rmkx Ns \0or Cd ke
8157 respectively: enable and disable the keypad.
8158 This is always enabled if available, because it seems even keyboards
8159 without keypads generate other key codes for, e.g., cursor keys in that
8160 case, and only if enabled we see the codes that we are interested in.
8162 .It Cd ed Ns \0or Cd cd
8166 .It Cd clear Ns \0or Cd cl
8168 clear the screen and home cursor.
8169 (Will be simulated via
8174 .It Cd home Ns \0or Cd ho
8179 .It Cd el Ns \0or Cd ce
8181 clear to the end of line.
8182 (Will be simulated via
8184 plus repetitions of space characters.)
8186 .It Cd hpa Ns \0or Cd ch
8187 .Cd column_address :
8188 move the cursor (to the given column parameter) in the current row.
8189 (Will be simulated via
8195 .Cd carriage_return :
8196 move to the first column in the current row.
8197 The default builtin fallback is
8200 .It Cd cub1 Ns \0or Cd le
8202 move the cursor left one space (non-destructively).
8203 The default builtin fallback is
8206 .It Cd cuf1 Ns \0or Cd nd
8208 move the cursor right one space (non-destructively).
8209 The default builtin fallback is
8211 which is used by most terminals.
8220 .It Va termcap-disable
8221 \*(OP Disable any interaction with a terminal control library.
8222 If set only some generic fallback builtins and possibly the content of
8224 describe the terminal to \*(UA.
8226 that this variable will only be queried once at program startup and can
8227 thus only be specified in resource files or on the command line.
8231 If defined, gives the number of lines of a message to be displayed
8234 normally, the first five lines are printed.
8238 The character set of the terminal \*(UA operates on,
8239 and the one and only supported character set that \*(UA can use if no
8240 character set conversion capabilities have been compiled into it,
8241 in which case it defaults to ISO-8859-1 unless it can deduce a value
8245 Refer to the section
8246 .Sx "Character sets"
8247 for the complete picture about character sets.
8251 For a safety-by-default policy \*(UA sets its process
8255 but this variable can be used to override that:
8256 set it to an empty value to don't change the (current) setting,
8257 otherwise the process file mode creation mask is updated to the new value.
8258 Child processes inherit the process file mode creation mask.
8261 .It Va user-HOST , user
8262 \*(IN Variable chain that sets a global fallback user name, which is
8263 used in case none has been given in the protocol and account-specific
8265 This variable defaults to the name of the user who runs \*(UA.
8269 \*(BO Setting this option enables upward compatibility with \*(UA
8270 version 15.0 in respect to which configuration options are available and
8271 how they are handled.
8272 This manual uses \*(IN and \*(OU to refer to the new and the old way of
8273 doing things, respectively.
8277 \*(BO Setting this option, also controllable via the command line option
8279 causes \*(UA to be more verbose, e.g., it will display obsoletion
8280 warnings and SSL/TLS certificate chains.
8281 Even though marked \*(BO this option may be set twice in order to
8282 increase the level of verbosity even more, in which case even details of
8283 the actual message delivery and protocol conversations are shown.
8286 is sufficient to disable verbosity as such.
8292 .It Va version , version-major , version-minor , version-update
8293 \*(RO \*(UA version information: the first variable contains a string
8294 containing the complete version identification \(en this is identical to
8295 the output of the command
8297 The latter three contain only digits: the major, minor and update
8301 .It Va writebackedited
8302 If this variable is set messages modified using the
8306 commands are written back to the current folder when it is quit;
8307 it is only honoured for writable folders in MBOX format, though.
8308 Note that the editor will be pointed to the raw message content in that
8309 case, i.e., neither MIME decoding nor decryption will have been
8310 performed, and proper RFC 4155
8312 quoting of newly added or edited content is also left as an excercise to
8316 .\" }}} (INTERNAL VARIABLES)
8319 .\" .Sh ENVIRONMENT {{{
8323 .Dq environment variable
8324 should be considered an indication that these variables are either
8325 standardized as vivid parts of process environments, or that they are
8326 commonly found in there.
8327 The process environment is inherited from the
8329 once \*(UA is started, and unless otherwise explicitly noted handling of
8330 the following variables transparently integrates into that of the
8331 .Sx "INTERNAL VARIABLES"
8332 from \*(UA's point of view.
8333 This means that, e.g., they can be managed via
8337 causing automatic program environment updates (to be inherited by
8338 newly created child processes).
8341 In order to transparently integrate other environment variables equally
8342 they need to be imported (linked) with the command
8344 This command can also be used to set and unset non-integrated
8345 environment variables from scratch, sufficient system support provided.
8346 The following example, applicable to a POSIX shell, sets the
8348 environment variable for \*(UA only, and beforehand exports the
8350 in order to affect any further processing in the running shell:
8352 .Bd -literal -offset indent
8353 $ EDITOR="vim -u ${HOME}/.vimrc"
8355 $ COLUMNS=80 \*(uA -R
8358 .Bl -tag -width ".It Ev _AILR_"
8361 The user's preferred width in column positions for the terminal screen
8363 Queried and used once on program startup, actively managed for child
8364 processes and the MLE (see
8365 .Sx "On terminal control and line editor" )
8366 in interactive mode thereafter.
8370 The name of the file to use for saving aborted messages if
8372 is set; this defaults to
8380 Pathname of the text editor to use in the
8384 .Sx "TILDE ESCAPES" .
8385 A default editor is used if this value is not defined.
8389 The user's home directory.
8390 This variable is only used when it resides in the process environment.
8397 .It Ev LANG , LC_ALL , LC_COLLATE , LC_CTYPE , LC_MESSAGES
8401 .Sx "Character sets" .
8402 (Only recognized by the system in the process environment.)
8406 The user's preferred number of lines on a page or the vertical screen
8407 or window size in lines.
8408 Queried and used once on program startup, actively managed for child
8409 processes in interactive mode thereafter.
8413 Pathname of the directory lister to use in the
8415 command when operating on local mailboxes.
8418 (path search through
8423 Upon startup \*(UA will actively ensure that this variable refers to the
8424 name of the user who runs \*(UA, in order to be able to pass a verified
8425 name to any newly created child process.
8429 Is used as the user's primary system mailbox, if set.
8430 Otherwise, a system-dependent default is used.
8431 Supports the special syntax conventions that are documented for the
8437 \*(OP Overrides the default path search for
8438 .Sx "The Mailcap files" ,
8439 which is defined in the standard RFC 1524 as
8440 .Ql ~/.mailcap:\:/etc/mailcap:\:/usr/etc/mailcap:\:/usr/local/etc/mailcap .
8441 .\" TODO we should have a mailcaps-default virtual RDONLY option!
8442 (\*(UA makes it a configuration option, however.)
8443 Note this is not a search path, but a path search.
8447 Is used as a startup file instead of
8450 When \*(UA scripts are invoked on behalf of other users,
8451 either this variable should be set to
8455 command line option should be used in order to avoid side-effects from
8456 reading their configuration files.
8457 This variable is only used when it resides in the process environment.
8461 The name of the user's mbox file.
8462 A logical subset of the special conventions that are documented for the
8467 The fallback default is
8472 Traditionally this secondary mailbox is used as the file to save
8473 messages from the primary system mailbox that have been read.
8475 .Sx "Message states" .
8478 .It Ev NAIL_NO_SYSTEM_RC
8479 If this variable is set then reading of
8481 at startup is inhibited, i.e., the same effect is achieved as if \*(UA
8482 had been started up with the option
8484 This variable is only used when it resides in the process environment.
8488 \*(IN\*(OP This variable overrides the default location of the user's
8494 Pathname of the program to use for backing the command
8498 variable enforces usage of a pager for output.
8499 The default paginator is
8501 (path search through
8504 \*(UA inspects the contents of this variable: if its contains the string
8506 then a non-existing environment variable
8513 dependent on whether terminal control support is available and whether
8514 that supports full (alternative) screen mode or not (also see
8515 .Sx "On terminal control and line editor" ) .
8519 will optionally be set to
8526 A list of directories that is searched by the shell when looking for
8527 commands (as such only recognized in the process environment).
8531 The shell to use for the commands
8537 and when starting subprocesses.
8538 A default shell is used if this option is not defined.
8542 \*(OP The terminal type for which output is to be prepared.
8543 For extended colour and font control please refer to
8544 .Sx "Coloured display" ,
8545 and for terminal management in general to
8546 .Sx "On terminal control and line editor" .
8550 Used as directory for temporary files instead of
8553 This variable is only used when it resides in the process environment.
8559 (see there), but this variable is not standardized, should therefore not
8560 be used, and is only corrected if already set.
8564 Pathname of the text editor to use in the
8568 .Sx "TILDE ESCAPES" .
8576 .Bl -tag -width ".It Pa _etc/mime.type_"
8578 File giving initial commands.
8581 System wide initialization file.
8585 \*(OP Personal MIME type handler definition file, see
8586 .Sx "The Mailcap files" .
8587 (RFC 1524 location, the actual path is a configuration option.)
8591 \*(OP System wide MIME type handler definition file, see
8592 .Sx "The Mailcap files" .
8593 (RFC 1524 location, the actual path is a configuration option.)
8596 .It Pa ~/.mime.types
8597 Personal MIME types, see
8598 .Sx "The mime.types files" .
8601 .It Pa /etc/mime.types
8602 System wide MIME types, see
8603 .Sx "The mime.types files" .
8607 \*(IN\*(OP The default location of the users
8609 file \(en the section
8610 .Sx "The .netrc file"
8611 documents the file format.
8614 .\" .Ss "The mime.types files" {{{
8615 .Ss "The mime.types files"
8617 When sending messages \*(UA tries to determine the content type of all
8619 When displaying message content or attachments \*(UA uses the content
8620 type to decide whether it can directly display data or whether it needs
8621 to deal with content handlers.
8622 It learns about MIME types and how to treat them by reading
8624 files, the loading of which can be controlled by setting the variable
8625 .Va mimetypes-load-control .
8628 can also be used to deal with MIME types.)
8630 files have the following syntax:
8633 .Dl type/subtype extension [extension ...]
8638 are strings describing the file contents, and one or multiple
8640 s, separated by whitespace, name the part of a filename starting after
8641 the last dot (of interest).
8642 Comments may be introduced anywhere on a line with a number sign
8644 causing the remaining line to be discarded.
8646 \*(UA also supports an extended, non-portable syntax in specially
8647 crafted files, which can be loaded via the alternative value syntax of
8648 .Va mimetypes-load-control
8649 and prepends an optional
8653 .Dl [type-marker ]type/subtype extension [extension ...]
8656 The following type markers are supported:
8659 .Bl -tag -compact -offset indent -width ".It Ar _n_u"
8661 Treat message parts with this content as plain text.
8666 Treat message parts with this content as HTML tagsoup.
8667 If the \*(OPal HTML-tagsoup-to-text converter is not available treat
8668 the content as plain text instead.
8672 but instead of falling back to plain text require an explicit content
8673 handler to be defined.
8678 for sending messages:
8680 .Va mime-allow-text-controls ,
8681 .Va mimetypes-load-control .
8682 For reading etc. messages:
8683 .Sx "HTML mail and MIME attachments" ,
8684 .Sx "The Mailcap files" ,
8686 .Va mime-counter-evidence ,
8687 .Va mimetypes-load-control ,
8688 .Va pipe-TYPE/SUBTYPE ,
8689 .Va pipe-EXTENSION .
8692 .\" .Ss "The Mailcap files" {{{
8693 .Ss "The Mailcap files"
8696 .Dq User Agent Configuration Mechanism
8697 which \*(UA \*(OPally supports.
8698 It defines a file format to be used to inform mail user agent programs
8699 about the locally-installed facilities for handling various data
8700 formats, i.e., about commands and how they can be used to display, edit
8701 etc. MIME part contents, as well as a default path search that includes
8702 multiple possible locations of
8706 environment variable that can be used to overwrite that (repeating here
8707 that it is not a search path, but instead a path search specification).
8708 Any existing files will be loaded in sequence, appending any content to
8709 the list of MIME type handler directives.
8713 files consist of a set of newline separated entries.
8714 Comment lines start with a number sign
8716 (in the first column!) and are ignored.
8717 Empty lines are also ignored.
8718 All other lines form individual entries that must adhere to the syntax
8720 To extend a single entry (not comment) its line can be continued on
8721 follow lines if newline characters are
8723 by preceding them with the reverse solidus character
8725 The standard doesn't specify how leading whitespace of follow lines is
8726 to be treated, therefore \*(UA retains it.
8730 entries consist of a number of semicolon
8732 separated fields, and the reverse solidus
8734 character can be used to escape any following character including
8735 semicolon and itself.
8736 The first two fields are mandatory and must occur in the specified
8737 order, the remaining fields are optional and may appear in any order.
8738 Leading and trailing whitespace of content is ignored (removed).
8741 The first field defines the MIME
8743 the entry is about to handle (case-insensitively, and no reverse solidus
8744 escaping is possible in this field).
8745 If the subtype is specified as an asterisk
8747 the entry is meant to match all subtypes of the named type, e.g.,
8749 would match any audio type.
8750 The second field defines the shell command which shall be used to
8752 MIME parts of the given type; it is implicitly called the
8759 shell commands message (MIME part) data is passed via standard input
8760 unless the given shell command includes one or more instances of the
8763 in which case these instances will be replaced with a temporary filename
8764 and the data will have been stored in the file that is being pointed to.
8767 shell commands data is assumed to be generated on standard output unless
8768 the given command includes (one ore multiple)
8770 In any case any given
8772 format is replaced with a(n already) properly quoted filename.
8773 Note that when a command makes use of a temporary file via
8775 then \*(UA will remove it again, as if the
8776 .Cd x-mailx-tmpfile ,
8777 .Cd x-mailx-tmpfile-fill
8779 .Cd x-mailx-tmpfile-unlink
8780 flags had been set; see below for more.
8783 The optional fields either define a shell command or an attribute (flag)
8784 value, the latter being a single word and the former being a keyword
8785 naming the field followed by an equals sign
8787 succeeded by a shell command, and as usual for any
8789 content any whitespace surrounding the equals sign will be removed, too.
8790 Optional fields include the following:
8793 .Bl -tag -width textualnewlines
8795 A program that can be used to compose a new body or body part in the
8802 field, but is to be used when the composing program needs to specify the
8804 header field to be applied to the composed data.
8808 A program that can be used to edit a body or body part in the given
8813 A program that can be used to print a message or body part in the given
8818 Specifies a program to be run to test some condition, e.g., the machine
8819 architecture, or the window system in use, to determine whether or not
8820 this mailcap entry applies.
8821 If the test fails, a subsequent mailcap entry should be sought; also see
8822 .Cd x-mailx-test-once .
8824 .It Cd needsterminal
8825 This flag field indicates that the given shell command must be run on
8826 an interactive terminal.
8827 \*(UA will temporarily release the terminal to the given command in
8828 interactive mode, in non-interactive mode this entry will be entirely
8829 ignored; this flag implies
8830 .Cd x-mailx-noquote .
8832 .It Cd copiousoutput
8833 A flag field which indicates that the output of the
8835 command will be an extended stream of textual output that can be
8836 (re)integrated into \*(UA's normal visual display.
8837 It is mutually exclusive with
8840 .Cd x-mailx-always .
8842 .It Cd textualnewlines
8843 A flag field which indicates that this type of data is line-oriented and
8846 all newlines should be converted to canonical form (CRLF) before
8847 encoding, and will be in that form after decoding.
8851 This field gives a file name format, in which
8853 will be replaced by a random string, the joined combination of which
8854 will be used as the filename denoted by
8855 .Ev NAIL_FILENAME_TEMPORARY .
8856 One could specify that a GIF file being passed to an image viewer should
8857 have a name ending in
8860 .Ql nametemplate=%s.gif .
8861 Note that \*(UA ignores the name template unless that solely specifies
8862 a filename suffix that consists of (ASCII) alphabetic and numeric
8863 characters, the underscore and dot only.
8866 Names a file, in X11 bitmap (xbm) format, which points to an appropriate
8867 icon to be used to visually denote the presence of this kind of data.
8868 This field is not used by \*(UA.
8871 A textual description that describes this type of data.
8873 .It Cd x-mailx-always
8874 Extension flag field that denotes that the given
8876 command shall be executed even if multiple messages will be displayed
8878 Normally messages which require external viewers that produce output
8879 which doesn't integrate into \*(UA's visual display (i.e., don't have
8881 set) have to be addressed directly and individually.
8882 (To avoid cases where, e.g., a thousand PDF viewer instances are spawned
8885 .It Cd x-mailx-even-if-not-interactive
8886 An extension flag test field \(em by default handlers without
8888 are entirely ignored in non-interactive mode, but if this flag is set
8889 then their use will be considered.
8890 It is an error if this flag is set for commands that use the flag
8893 .It Cd x-mailx-noquote
8894 An extension flag field that indicates that even a
8897 command shall not be used to generate message quotes
8898 (as it would be by default).
8900 .It Cd x-mailx-async
8901 Extension flag field that denotes that the given
8903 command shall be executed asynchronously, without blocking \*(UA.
8904 Cannot be used in conjunction with
8907 .It Cd x-mailx-test-once
8908 Extension flag which denotes whether the given
8910 command shall be evaluated once only and the (boolean) result be cached.
8911 This is handy if some global unchanging condition is to be queried, like
8912 .Dq running under the X Window System .
8914 .It Cd x-mailx-tmpfile
8915 Extension flag field that requests creation of a zero-sized temporary
8916 file, the name of which is to be placed in the environment variable
8917 .Ev NAIL_FILENAME_TEMPORARY .
8918 It is an error to use this flag with commands that include a
8922 .It Cd x-mailx-tmpfile-fill
8923 Normally the MIME part content is passed to the handler via standard
8924 input; if this flag is set then the data will instead be written into
8926 .Cd x-mailx-tmpfile .
8927 In order to cause deletion of the temporary file you will have to set
8928 .Cd x-mailx-tmpfile-unlink
8930 It is an error to use this flag with commands that include a
8934 .It Cd x-mailx-tmpfile-unlink
8935 Extension flag field that requests that the temporary file shall be
8936 deleted automatically when the command loop is entered again at latest.
8937 (Don't use this for asynchronous handlers.)
8938 It is an error to use this flag with commands that include a
8940 format, or without also setting
8943 .Cd x-mailx-tmpfile-fill .
8945 .It Cd x-mailx-tmpfile-keep
8948 implies the three tmpfile related flags above, but if you want, e.g.,
8950 and deal with the temporary file yourself, you can add in this flag to
8952 .Cd x-mailx-tmpfile-unlink .
8957 The standard includes the possibility to define any number of additional
8958 entry fields, prefixed by
8960 Flag fields apply to the entire
8962 entry \(em in some unusual cases, this may not be desirable, but
8963 differentiation can be accomplished via separate entries, taking
8964 advantage of the fact that subsequent entries are searched if an earlier
8965 one does not provide enough information.
8968 command needs to specify the
8972 command shall not, the following will help out the latter (with enabled
8976 level \*(UA will show information about handler evaluation):
8978 .Bd -literal -offset indent
8979 application/postscript; ps-to-terminal %s; needsterminal
8980 application/postscript; ps-to-terminal %s; compose=idraw %s
8984 In fields any occurrence of the format string
8986 will be replaced by the
8989 Named parameters from the
8991 field may be placed in the command execution line using
8993 followed by the parameter name and a closing
8996 The entire parameter should appear as a single command line argument,
8997 regardless of embedded spaces; thus:
8999 .Bd -literal -offset indent
9001 Content-type: multipart/mixed; boundary=42
9004 multipart/*; /usr/local/bin/showmulti \e
9005 %t %{boundary} ; composetyped = /usr/local/bin/makemulti
9007 # Executed shell command
9008 /usr/local/bin/showmulti multipart/mixed 42
9012 .\" TODO v15: Mailcap: %n,%F
9013 Note that \*(UA doesn't support handlers for multipart MIME parts as
9014 shown in this example (as of today).
9015 \*(UA doesn't support the additional formats
9019 An example file, also showing how to properly deal with the expansion of
9021 which includes any quotes that are necessary to make it a valid shell
9022 argument by itself and thus will cause undesired behaviour when placed
9023 in additional user-provided quotes:
9025 .Bd -literal -offset indent
9027 text/richtext; richtext %s; copiousoutput
9029 text/x-perl; perl -cWT %s
9033 trap "rm -f ${infile}" EXIT\e; \e
9034 trap "exit 75" INT QUIT TERM\e; \e
9036 x-mailx-async; x-mailx-tmpfile-keep
9038 application/*; echo "This is \e"%t\e" but \e
9039 is 50 \e% Greek to me" \e; < %s head -c 1024 | cat -vET; \e
9040 copiousoutput; x-mailx-noquote
9045 .Sx "HTML mail and MIME attachments" ,
9046 .Sx "The mime.types files" ,
9049 .Va mime-counter-evidence ,
9050 .Va pipe-TYPE/SUBTYPE ,
9051 .Va pipe-EXTENSION .
9054 .\" .Ss "The .netrc file" {{{
9055 .Ss "The .netrc file"
9059 file contains user credentials for machine accounts.
9060 The default location in the user's
9062 directory may be overridden by the
9064 environment variable.
9065 The file consists of space, tabulator or newline separated tokens.
9066 \*(UA implements a parser that supports a superset of the original BSD
9067 syntax, but users should nonetheless be aware of portability glitches
9068 of that file format, shall their
9070 be usable across multiple programs and platforms:
9073 .Bl -bullet -compact
9075 BSD doesn't support single, but only double quotation marks, e.g.,
9076 .Ql password="pass with spaces" .
9078 BSD (only?) supports escaping of single characters via a reverse solidus
9079 (e.g., a space can be escaped via
9081 in- as well as outside of a quoted string.
9083 BSD doesn't require the final quotation mark of the final user input token.
9085 The original BSD (Berknet) parser also supported a format which allowed
9086 tokens to be separated with commas \(en whereas at least Hewlett-Packard
9087 still seems to support this syntax, \*(UA does not!
9089 As a non-portable extension some widely-used programs support
9090 shell-style comments: if an input line starts, after any amount of
9091 whitespace, with a number sign
9093 then the rest of the line is ignored.
9095 Whereas other programs may require that the
9097 file is accessible by only the user if it contains a
9103 \*(UA will always require these strict permissions.
9107 Of the following list of supported tokens \*(UA only uses (and caches)
9112 At runtime the command
9114 can be used to control \*(UA's
9118 .Bl -tag -width password
9119 .It Cd machine Ar name
9120 The hostname of the entries' machine, lowercase-normalized by \*(UA
9122 Any further file content, until either end-of-file or the occurrence
9127 first-class token is bound (only related) to the machine
9130 As an extension that shouldn't be the cause of any worries
9131 \*(UA supports a single wildcard prefix for
9133 .Bd -literal -offset indent
9134 machine *.example.com login USER password PASS
9135 machine pop3.example.com login USER password PASS
9136 machine smtp.example.com login USER password PASS
9142 .Ql pop3.example.com ,
9146 .Ql local.smtp.example.com .
9147 Note that in the example neither
9148 .Ql pop3.example.com
9150 .Ql smtp.example.com
9151 will be matched by the wildcard, since the exact matches take
9152 precedence (it is however faster to specify it the other way around).
9157 except that it is a fallback entry that is used shall none of the
9158 specified machines match; only one default token may be specified,
9159 and it must be the last first-class token.
9161 .It Cd login Ar name
9162 The user name on the remote machine.
9164 .It Cd password Ar string
9165 The user's password on the remote machine.
9167 .It Cd account Ar string
9168 Supply an additional account password.
9169 This is merely for FTP purposes.
9171 .It Cd macdef Ar name
9173 A macro is defined with the specified
9175 it is formed from all lines beginning with the next line and continuing
9176 until a blank line is (consecutive newline characters are) encountered.
9179 entries cannot be utilized by multiple machines, too, but must be
9180 defined following the
9182 they are intended to be used with.)
9185 exists, it is automatically run as the last step of the login process.
9186 This is merely for FTP purposes.
9193 .\" .Sh EXAMPLES {{{
9196 .\" .Ss "An example configuration" {{{
9197 .Ss "An example configuration"
9199 .Bd -literal -offset indent
9200 # This example assumes v15.0 compatibility mode
9203 # Where are the up-to-date SSL certificates?
9204 #set ssl-ca-dir=/etc/ssl/certs
9205 set ssl-ca-file=/etc/ssl/certs/ca-certificates.crt
9207 # (Since we manage up-to-date ones explicitly, don't use any,
9208 # possibly outdated, default certificates shipped with OpenSSL)
9209 set ssl-no-default-ca
9211 # Don't use protocols older than TLS v1.2.
9212 # Change this only when the remote server doesn't support it:
9213 # maybe use ssl-protocol-HOST (or -USER@HOST) syntax to define
9214 # such explicit exceptions, then
9215 set ssl-protocol='-ALL,+TLSv1.2'
9217 # Explicitly define the list of ciphers, which may improve security,
9218 # especially with protocols older than TLS v1.2. See ciphers(1).
9219 # Including "@STRENGTH" will sort the final list by algorithm strength.
9220 # In reality it is possibly best to only use ssl-cipher-list-HOST
9221 # (or -USER@HOST), as necessary, again..
9222 set ssl-cipher-list=TLSv1.2:!aNULL:!eNULL:!MEDIUM:!LOW:!EXPORT:@STRENGTH
9223 # ALL:!aNULL:!MEDIUM:!LOW:!MD5:!RC4:!EXPORT:@STRENGTH
9225 # Request strict transport security checks!
9226 set ssl-verify=strict
9228 # Essential setting: select allowed character sets
9229 set sendcharsets=utf-8,iso-8859-1
9231 # A very kind option: when replying to a message, first try to
9232 # use the same encoding that the original poster used herself!
9233 set reply-in-same-charset
9235 # When replying to or forwarding a message the comment and name
9236 # parts of email addresses are removed unless this variable is set
9239 # When sending messages, wait until the Mail-Transfer-Agent finishs.
9240 # Only like this you'll be able to see errors reported through the
9241 # exit status of the MTA (including the builtin SMTP one)!
9244 # Only use builtin MIME types, no mime.types(5) files
9245 set mimetypes-load-control
9247 # Default directory where we act in (relative to $HOME)
9249 # A leading "+" (often) means: under *folder*
9250 # *record* is used to save copies of sent messages
9251 set MBOX=+mbox.mbox record=+sent.mbox DEAD=+dead.txt
9253 # Make "file mymbox" and "file myrec" go to..
9254 shortcut mymbox %:+mbox.mbox myrec +sent.mbox
9256 # Not really optional, e.g., for S/MIME
9257 set from='Your Name <address@exam.ple>'
9259 # It may be necessary to set hostname and/or smtp-hostname
9260 # if the "SERVER" of smtp and "domain" of from don't match.
9261 # The `urlencode' command can be used to encode USER and PASS
9262 set smtp=(smtp[s]/submission)://[USER[:PASS]@]SERVER[:PORT] \e
9263 smtp-auth=login/plain... \e
9266 # Never refuse to start into interactive mode, and more
9268 colour-pager crt= \e
9269 followup-to followup-to-honour=ask-yes \e
9270 history-file=+.\*(uAhist history-size=-1 history-gabby \e
9271 mime-counter-evidence=0xE \e
9272 prompt='?\e?[\e$ \e@]\e& ' \e
9273 reply-to-honour=ask-yes \e
9276 # When `t'yping messages, show only these headers
9277 # (use `T'ype for all headers and `S'how for raw message)
9278 retain date from to cc subject
9280 # Some mailing lists
9281 mlist '@xyz-editor\e.xyz$' '@xyzf\e.xyz$'
9282 mlsubscribe '^xfans@xfans\e.xyz$'
9284 # A real life example of a very huge free mail provider
9286 set folder=~/spool/XooglX MAIL=+syste.mbox sent=+sent
9287 set from='Your Name <address@examp.ple>'
9288 # (The plain smtp:// proto is optional)
9289 set smtp=USER:PASS@smtp.gmXil.com smtp-use-starttls
9292 # Here is a pretty large one which does not allow sending mails
9293 # if there is a domain name mismatch on the SMTP protocol level,
9294 # which would bite us if the value of from does not match, e.g.,
9295 # for people who have a sXXXXeforge project and want to speak
9296 # with the mailing list under their project account (in from),
9297 # still sending the message through their normal mail provider
9299 set folder=~/spool/XandeX MAIL=+syste.mbox sent=+sent
9300 set from='Your Name <address@exam.ple>'
9301 set smtp=smtps://USER:PASS@smtp.yaXXex.ru:465 \e
9302 hostname=yaXXex.com smtp-hostname=
9305 # Create some new commands so that, e.g., `ls /tmp' will..
9306 wysh ghost lls '!ls ${LS_COLOR_FLAG} -aFlrS'
9307 wysh ghost llS '!ls ${LS_COLOR_FLAG} -aFlS'
9308 wysh ghost ls '!ls ${LS_COLOR_FLAG} -aFrS'
9309 wysh ghost lS '!ls ${LS_COLOR_FLAG} -aFS'
9310 wysh ghost lla '!ls ${LS_COLOR_FLAG} -aFlr'
9311 wysh ghost llA '!ls ${LS_COLOR_FLAG} -aFl'
9312 wysh ghost la '!ls ${LS_COLOR_FLAG} -aFr'
9313 wysh ghost lA '!ls ${LS_COLOR_FLAG} -aF'
9314 wysh ghost ll '!ls ${LS_COLOR_FLAG} -aFltr'
9315 wysh ghost lL '!ls ${LS_COLOR_FLAG} -aFlt'
9316 wysh ghost l '!ls ${LS_COLOR_FLAG} -aFtr'
9317 wysh ghost L '!ls ${LS_COLOR_FLAG} -aFt'
9319 # We don't support gpg(1) directly yet. But simple --clearsign'd
9320 # message parts can be dealt with as follows:
9322 wysh set pipe-text/plain=$'@*#++=@\e
9323 < "${NAIL_FILENAME_TEMPORARY}" awk \e
9324 -v TMPFILE="${NAIL_FILENAME_TEMPORARY}" \e'\e
9326 /^-----BEGIN PGP SIGNED MESSAGE-----/,/^$/{\e
9329 print "--- GPG --verify ---";\e
9330 system("gpg --verify " TMPFILE " 2>&1");\e
9331 print "--- GPG --verify ---";\e
9335 /^-----BEGIN PGP SIGNATURE-----/,\e
9336 /^-----END PGP SIGNATURE-----/{\e
9346 !printf 'Key IDs to gpg --recv-keys: ';\e
9348 gpg --recv-keys ${keyids};
9354 When storing passwords in
9356 appropriate permissions should be set on this file with
9357 .Ql $ chmod 0600 \*(ur .
9360 is available user credentials can be stored in the central
9362 file instead; e.g., here is a different version of the example account
9363 that sets up SMTP and POP3:
9365 .Bd -literal -offset indent
9367 set folder=~/spool/XandeX MAIL=+syste.mbox sent=+sent
9368 set from='Your Name <address@exam.ple>'
9370 # Load an encrypted ~/.netrc by uncommenting the next line
9371 #set netrc-pipe='gpg -qd ~/.netrc.pgp'
9373 set smtp=smtps://smtp.yXXXXx.ru:465 \e
9374 smtp-hostname= hostname=yXXXXx.com
9375 set pop3-keepalive=240 pop3-no-apop-pop.yXXXXx.ru
9376 ghost xp fi pop3s://pop.yXXXXx.ru
9385 .Bd -literal -offset indent
9386 machine *.yXXXXx.ru login USER password PASS
9390 This configuration should now work just fine:
9393 .Dl $ echo text | \*(uA -vv -AXandeX -s Subject user@exam.ple
9396 .\" .Ss "Signed and encrypted messages with S/MIME" {{{
9397 .Ss "Signed and encrypted messages with S/MIME"
9399 \*(OP S/MIME provides two central mechanisms:
9400 message signing and message encryption.
9401 A signed message contains some data in addition to the regular text.
9402 The data can be used to verify that the message was sent using a valid
9403 certificate, that the sender's address in the message header matches
9404 that in the certificate, and that the message text has not been altered.
9405 Signing a message does not change its regular text;
9406 it can be read regardless of whether the recipient's software is able to
9410 It is thus usually possible to sign all outgoing messages if so desired.
9411 Encryption, in contrast, makes the message text invisible for all people
9412 except those who have access to the secret decryption key.
9413 To encrypt a message, the specific recipient's public encryption key
9415 It is therefore not possible to send encrypted mail to people unless their
9416 key has been retrieved from either previous communication or public key
9418 A message should always be signed before it is encrypted.
9419 Otherwise, it is still possible that the encrypted message text is
9423 A central concept to S/MIME is that of the certification authority (CA).
9424 A CA is a trusted institution that issues certificates.
9425 For each of these certificates it can be verified that it really
9426 originates from the CA, provided that the CA's own certificate is
9428 A set of CA certificates is usually delivered with OpenSSL and installed
9430 If you trust the source of your OpenSSL software installation,
9431 this offers reasonable security for S/MIME on the Internet.
9433 .Va ssl-no-default-ca
9437 .Va smime-ca-dir . )
9438 In general, a certificate cannot be more secure than the method its CA
9439 certificate has been retrieved with, though.
9440 Thus if you download a CA certificate from the Internet,
9441 you can only trust the messages you verify using that certificate as
9442 much as you trust the download process.
9445 The first thing you need for participating in S/MIME message exchange is
9446 your personal certificate, including a private key.
9447 The certificate contains public information, in particular your name and
9448 your email address(es), and the public key that is used by others to
9449 encrypt messages for you,
9450 and to verify signed messages they supposedly received from you.
9451 The certificate is included in each signed message you send.
9452 The private key must be kept secret.
9453 It is used to decrypt messages that were previously encrypted with your
9454 public key, and to sign messages.
9457 For personal use it is recommended that you get a S/MIME certificate
9458 from one of the major CAs on the Internet using your WWW browser.
9459 Many CAs offer such certificates for free.
9461 .Lk https://www.CAcert.org
9462 which issues client and server certificates to members of their
9463 community for free; their root certificate
9464 .Pf ( Lk https://\:www.cacert.org/\:certs/\:root.crt )
9465 is often not in the default set of trusted CA root certificates, though,
9466 which means you will have to download their root certificate separately
9467 and ensure it is part of our S/MIME certificate validation chain by
9470 or as a vivid member of the
9472 But let's take a step-by-step tour on how to setup S/MIME with
9473 a certificate from CAcert.org despite this situation!
9476 First of all you will have to become a member of the CAcert.org
9477 community, simply by registrating yourself via the web interface.
9478 Once you are, create and verify all email addresses you want to be able
9479 to create signed and encrypted messages for/with using the corresponding
9480 entries of the web interface.
9481 Now ready to create S/MIME certificates, so let's create a new
9482 .Dq client certificate ,
9483 ensure to include all email addresses that should be covered by the
9484 certificate in the following web form, and also to use your name as the
9488 Create a private key and a certificate request on your local computer
9489 (please see the manual pages of the used commands for more in-depth
9490 knowledge on what the used arguments etc. do):
9493 .Dl openssl req -nodes -newkey rsa:4096 -keyout key.pem -out creq.pem
9496 Afterwards copy-and-paste the content of
9498 into the certificate-request (CSR) field of the web form on the
9499 CAcert.org website (you may need to unfold some
9500 .Dq advanced options
9501 to see the corresponding text field).
9502 This last step will ensure that your private key (which never left your
9503 box) and the certificate belong together (through the public key that
9504 will find its way into the certificate via the certificate-request).
9505 You are now ready and can create your CAcert certified certificate.
9506 Download and store or copy-and-paste it as
9511 In order to use your new S/MIME setup you will have to create
9512 a combined private key/public key (certificate) file:
9515 .Dl cat key.pem pub.crt > ME@HERE.com.paired
9518 This is the file \*(UA will work with.
9519 If you have created your private key with a passphrase then \*(UA will
9520 ask you for it whenever a message is signed or decrypted.
9521 Set the following variables to henceforth use S/MIME (setting
9523 is of interest for verification only):
9525 .Bd -literal -offset indent
9526 set smime-ca-file=ALL-TRUSTED-ROOT-CERTS-HERE \e
9527 smime-sign-cert=ME@HERE.com.paired \e
9528 smime-sign-message-digest=SHA256 \e
9533 From each signed message you send, the recipient can fetch your
9534 certificate and use it to send encrypted mail back to you.
9535 Accordingly if somebody sends you a signed message, you can do the same,
9538 command to check the validity of the certificate.
9541 Variables of interest for S/MIME signing:
9545 .Va smime-crl-file ,
9546 .Va smime-no-default-ca ,
9548 .Va smime-sign-cert ,
9549 .Va smime-sign-include-certs
9551 .Va smime-sign-message-digest .
9554 After it has been verified save the certificate via
9556 and tell \*(UA that it should use it for encryption for further
9557 communication with that somebody:
9559 .Bd -literal -offset indent
9561 set smime-encrypt-USER@HOST=FILENAME \e
9562 smime-cipher-USER@HOST=AES256
9566 Additional variables of interest for S/MIME en- and decryption:
9569 .Va smime-encrypt-USER@HOST .
9572 You should carefully consider if you prefer to store encrypted messages
9574 If you do, anybody who has access to your mail folders can read them,
9575 but if you do not, you might be unable to read them yourself later if
9576 you happen to lose your private key.
9579 command saves messages in decrypted form, while the
9583 commands leave them encrypted.
9586 Note that neither S/MIME signing nor encryption applies to message
9587 subjects or other header fields yet.
9588 Thus they may not contain sensitive information for encrypted messages,
9589 and cannot be trusted even if the message content has been verified.
9590 When sending signed messages,
9591 it is recommended to repeat any important header information in the
9595 .\" .Ss "Using CRLs with S/MIME or SSL/TLS" {{{
9596 .Ss "Using CRLs with S/MIME or SSL/TLS"
9598 \*(OP Certification authorities (CAs) issue certificate revocation
9599 lists (CRLs) on a regular basis.
9600 These lists contain the serial numbers of certificates that have been
9601 declared invalid after they have been issued.
9602 Such usually happens because the private key for the certificate has
9604 because the owner of the certificate has left the organization that is
9605 mentioned in the certificate, etc.
9606 To seriously use S/MIME or SSL/TLS verification,
9607 an up-to-date CRL is required for each trusted CA.
9608 There is otherwise no method to distinguish between valid and
9609 invalidated certificates.
9610 \*(UA currently offers no mechanism to fetch CRLs, nor to access them on
9611 the Internet, so you have to retrieve them by some external mechanism.
9614 \*(UA accepts CRLs in PEM format only;
9615 CRLs in DER format must be converted, like, e.\|g.:
9618 .Dl $ openssl crl \-inform DER \-in crl.der \-out crl.pem
9621 To tell \*(UA about the CRLs, a directory that contains all CRL files
9622 (and no other files) must be created.
9627 variables, respectively, must then be set to point to that directory.
9628 After that, \*(UA requires a CRL to be present for each CA that is used
9629 to verify a certificate.
9632 .\" .Ss "Handling spam" {{{
9635 \*(OP \*(UA can make use of several spam interfaces for the purpose of
9636 identification of, and, in general, dealing with spam messages.
9637 A precondition of most commands in order to function is that the
9639 variable is set to one of the supported interfaces.
9640 Once messages have been identified as spam their (volatile)
9642 state can be prompted: the
9646 message specifications will address respective messages and their
9648 entries will be used when displaying the
9650 in the header display.
9655 rates the given messages and sets their
9658 If the spam interface offers spam scores those can also be displayed in
9659 the header display by including the
9669 will interact with the Bayesian filter of the chosen interface and learn
9670 the given messages as
9674 respectively; the last command can be used to cause
9676 of messages; it adheres to their current
9678 state and thus reverts previous teachings.
9683 will simply set and clear, respectively, the mentioned volatile
9685 message flag, without any interface interaction.
9692 .Va spam-interface Ns s
9696 require a running instance of the
9698 server in order to function, started with the option
9700 shall Bayesian filter learning be possible.
9702 only works via a local path-based
9704 socket, but otherwise the following will be equivalently fine:
9706 .Bd -literal -offset indent
9707 $ spamd -i localhost:2142 -i /tmp/.spamsock -d [-L] [-l]
9708 $ spamd --listen=localhost:2142 --listen=/tmp/.spamsock \e
9709 --daemonize [--local] [--allow-tell]
9713 Thereafter \*(UA can make use of these interfaces:
9715 .Bd -literal -offset indent
9716 $ \*(uA -Sspam-interface=spamd -Sspam-maxsize=500000 \e
9717 -Sspamd-socket=/tmp/.spamsock -Sspamd-user=
9719 $ \*(uA -Sspam-interface=spamc -Sspam-maxsize=500000 \e
9720 -Sspamc-command=/usr/local/bin/spamc \e
9721 -Sspamc-arguments="-U /tmp/.spamsock" -Sspamc-user=
9723 $ \*(uA -Sspam-interface=spamc -Sspam-maxsize=500000 \e
9724 -Sspamc-command=/usr/local/bin/spamc \e
9725 -Sspamc-arguments="-d localhost -p 2142" -Sspamc-user=
9729 Using the generic filter approach allows usage of programs like
9731 Here is an example, requiring it to be accessible via
9734 .Bd -literal -offset indent
9735 $ \*(uA -Sspam-interface=filter -Sspam-maxsize=500000 \e
9736 -Sspamfilter-ham="bogofilter -n" \e
9737 -Sspamfilter-noham="bogofilter -N" \e
9738 -Sspamfilter-nospam="bogofilter -S" \e
9739 -Sspamfilter-rate="bogofilter -TTu 2>/dev/null" \e
9740 -Sspamfilter-spam="bogofilter -s" \e
9741 -Sspamfilter-rate-scanscore="1;^(.+)$"
9745 Because messages must exist on local storage in order to be scored (or
9746 used for Bayesian filter training), it is possibly a good idea to
9747 perform the local spam check last:
9749 .Bd -literal -offset indent
9750 define spamdelhook {
9752 spamset (header x-dcc-brand-metrics "bulk")
9753 # Server-side spamassassin(1)
9754 spamset (header x-spam-flag "YES")
9755 del :s # TODO we HAVE to be able to do `spamrate :u ! :sS'
9761 set folder-hook-FOLDER=spamdelhook
9765 See also the documentation for the variables
9766 .Va spam-interface , spam-maxsize ,
9767 .Va spamc-command , spamc-arguments , spamc-user ,
9768 .Va spamd-socket , spamd-user ,
9769 .Va spamfilter-ham , spamfilter-noham , spamfilter-nospam , \
9772 .Va spamfilter-rate-scanscore .
9780 .\" .Ss "\*(UA shortly hangs on startup" {{{
9781 .Ss "\*(UA shortly hangs on startup"
9783 This can have two reasons, one is the necessity to wait for a file lock
9784 and can't be helped, the other being that \*(UA calls the function
9786 in order to query the nodename of the box (sometimes the real one is
9787 needed instead of the one represented by the internal variable
9789 You may have varying success by ensuring that the real hostname and
9793 or, more generally, that the name service is properly setup \(en
9796 return what you'd expect?
9797 Does this local hostname has a domain suffix?
9798 RFC 6762 standardized the link-local top-level domain
9802 .\" .Ss "I can't login to Google mail aka GMail" {{{
9803 .Ss "I can't login to Google mail aka GMail"
9805 Since 2014 some free service providers classify programs as
9807 unless they use a special authentification method (OAuth 2.0) which
9808 wasn't standardized for non-HTTP protocol authentication token query
9809 until August 2015 (RFC 7628).
9812 Different to Kerberos / GSSAPI, which is developed since the mid of the
9813 1980s, where a user can easily create a local authentication ticket for
9814 her- and himself with the locally installed
9816 program, that protocol has no such local part but instead requires
9817 a world-wide-web query to create or fetch a token; since there is no
9818 local cache this query has to be performed whenever \*(UA is invoked
9819 from the command line (in interactive sessions situation may differ).
9822 \*(UA doesn't support OAuth.
9823 Because of this it is necessary to declare \*(UA a
9825 (on the providers account web page) in order to read and send mail.
9826 However, it also seems possible to take the following steps instead:
9831 give the provider the number of a mobile phone,
9834 .Dq 2-Step Verification ,
9836 create an application specific password (16 characters), and
9838 use that special password instead of your real Google account password in
9839 \*(UA (for more on that see the section
9840 .Sx "On URL syntax and credential lookup" ) .
9846 .\" .Sh "SEE ALSO" {{{
9859 .Xr spamassassin 1 ,
9880 M. Douglas McIlroy writes in his article
9881 .Dq A Research UNIX Reader: Annotated Excerpts \
9882 from the Programmer's Manual, 1971-1986
9885 command already appeared in First Edition
9889 .Bd -ragged -offset indent
9890 Electronic mail was there from the start.
9891 Never satisfied with its exact behavior, everybody touched it at one
9892 time or another: to assure the safety of simultaneous access, to improve
9893 privacy, to survive crashes, to exploit uucp, to screen out foreign
9894 freeloaders, or whatever.
9895 Not until v7 did the interface change (Thompson).
9896 Later, as mail became global in its reach, Dave Presotto took charge and
9897 brought order to communications with a grab-bag of external networks
9903 Mail was written in 1978 by Kurt Shoens and developed as part of the
9906 distribution until 1995.
9907 Mail has then seen further development in open source
9909 variants, noticeably by Christos Zoulas in
9911 Basing upon this Nail, later Heirloom Mailx, was developed by Gunnar
9912 Ritter in the years 2000 until 2008.
9913 Since 2012 S-nail is maintained by Steffen (Daode) Nurpmeso.
9914 This man page is derived from
9915 .Dq The Mail Reference Manual
9916 that was originally written by Kurt Shoens.
9923 .An "Christos Zoulas" ,
9924 .An "Gunnar Ritter" ,
9925 .An "Steffen Nurpmeso" Aq Mt s-nail-users@lists.sourceforge.net
9927 .Mt s-mailx@sdaoden.eu ) .
9933 Limitations with POP3 mailboxes are:
9934 The line count for the header display is only appropriate if the entire
9935 message has been downloaded from the server.
9936 The status field of a message is maintained by the server between
9937 connections; some servers do not update it at all, and with a server
9940 command will not cause the message status to be reset.
9945 variable have no effect.
9952 is typed while a POP3 operation is in progress, \*(UA will wait
9953 until the operation can be safely aborted, and will then return to the
9954 command loop and print the prompt again.
9957 is typed while \*(UA is waiting for the operation to complete, the
9958 operation itself will be cancelled.
9959 In this case, data that has not been fetched yet will have to be fetched
9960 before the next command can be performed.
9961 If the cancelled operation was using an SSL/TLS encrypted channel,
9962 an error in the SSL transport will very likely result and render the
9963 connection unusable.
9966 As \*(UA is a mail user agent, it provides only basic SMTP services.
9967 If it fails to contact its upstream SMTP server, it will not make
9968 further attempts to transfer the message at a later time,
9969 and it does not leave other information about this condition than an
9970 error message on the terminal and an entry in
9972 This is usually not a problem if the SMTP server is located in the same
9973 local network as the computer on which \*(UA is run.
9974 However, care should be taken when using a remote server of an ISP;
9975 it might be better to set up a local SMTP server then which just acts as
9984 from the repository.
9986 After deleting some message of a POP3 mailbox the header summary falsely
9987 claims that there are no messages to display, you need to perform
9988 a scroll or dot movement to restore proper state.
9990 In threaded display a power user may encounter crashes very
9991 occasionally (this is may and very).