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>.
9 .\" Redistribution and use in source and binary forms, with or without
10 .\" modification, are permitted provided that the following conditions
12 .\" 1. Redistributions of source code must retain the above copyright
13 .\" notice, this list of conditions and the following disclaimer.
14 .\" 2. Redistributions in binary form must reproduce the above copyright
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17 .\" 3. All advertising materials mentioning features or use of this software
18 .\" must display the following acknowledgement:
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.
24 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS 'AS IS' AND
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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]
66 .Nd send and receive Internet mail
79 .Op Fl a Ar attachment
82 .Op Fl q Ar quote-file
84 .Op Fl S Ar variable Ns Op Ns = Ns Ar value
89 .Op Fl Fl \~ Ns Ar mta-option ...
98 .Op Fl S Ar variable Ns Op Ns = Ns Ar value
101 .Op Fl Fl \~ Ns Ar mta-option ...
108 .Op Fl L Ar spec-list
109 .Op Fl r Ar from-addr
110 .Op Fl S Ar variable Ns Op Ns = Ns Ar value
113 .Op Fl Fl \~ Ns Ar mta-option ...
118 .Mx -toc -tree html pdf ps xhtml
121 .\" .Sh DESCRIPTION {{{
124 .Bd -filled -compact -offset indent
125 .Sy Compatibility note:
126 S-nail (\*(UA) will wrap up into \%S-mailx in v15.0 (circa 2018).
127 Backward incompatibility has to be expected.
128 New and old behaviour is flagged \*(IN and \*(OU, and setting
131 .Sx "INTERNAL VARIABLES" ,
132 will choose new behaviour when applicable.
133 \*(OB flags what will vanish, and enabling
137 enables obsoletion warnings.
141 \*(UA is a mail processing system with a command syntax reminiscent of
143 with lines replaced by messages.
144 It is intended to provide the functionality of the POSIX
146 command, but is MIME capable and optionally offers extensions for
147 line editing, S/MIME, SMTP and POP3 among others.
148 It is usable as a mail batch language.
150 .\" .Ss "Options" {{{
153 .Bl -tag -width ".Fl _ Ar _ccount"
156 Explicitly control which of the
158 shall be loaded: if the letter
160 is (case-insensitively) part of the
164 is loaded, likewise the letter
166 controls loading of the user's personal
168 file, whereas the letters
172 explicitly forbid loading of any resource files.
173 This option should be used by scripts: to avoid environmental noise they
176 from any configuration files and create a script-local environment,
177 explicitly setting any desired variable via
179 This option overrides
186 command (see below) for
188 after the startup files have been read.
192 Attach the given file to the message.
193 The same filename conventions as described in the section
195 apply: shell word expansion is restricted to the tilde
200 not be accessible but contain a
202 character, then anything after the
204 is assumed to specify the input character set and anything before
206 the filename: this is the only option to specify the input character set
207 (and don't perform any character set conversion) for text attachments
208 from the command line, not using the
210 tilde escape command.
214 Make standard input and standard output line-buffered.
218 Send a blind carbon copy to
220 Can be used multiple times, but it is also possible to give
221 a comma-separated list of receivers in a single argument, proper shell
222 quoting provided, e.g.,
223 .Ql -b """qrec1 , rec2,rec3, Ex <am@ple>""" .
225 .Sx "On sending mail, and non-interactive mode" .
229 Send carbon copies to the given receiver(s).
230 Can be used multiple times.
236 variable which enables debug messages and disables message delivery,
237 among others; effectively turns almost any operation into a dry-run.
243 variable and thus discard messages with an empty message part body.
244 This is useful for sending messages from scripts.
248 Just check if mail is present (in the specified or system mailbox).
249 If yes, return an exit status of zero, a non-zero value otherwise.
250 To restrict the set of mails to consider in this evaluation a message
251 specification can be added with the option
256 Save the message to send in a file named after the local part of the
257 first recipient's address (instead of in
262 Read in the contents of the user's
264 (or the specified file) for processing;
265 when \*(UA is quit, it writes undeleted messages back to this file
269 Some special conventions are recognized for the string
271 which are documented for the
276 is not a direct argument to the flag
278 but is instead taken from the command line after option processing has
282 that starts with a hyphen, prefix it with a (relative) path, as in
283 .Ql ./-hyphenbox.mbox .
287 Display a summary of the
289 of all messages in the specified or system mailbox and exit.
290 A configurable summary view is available via the
296 Show a short usage summary.
297 Because of widespread use a
299 argument will have the same effect.
305 variable to ignore tty interrupt signals.
308 .It Fl L Ar spec-list
309 Display a summary of all
311 of only those messages in the specified or system mailbox that match the
316 .Sx "Specifying messages"
323 option has been given in addition no header summary is produced,
324 but \*(UA will instead indicate via its exit status wether
330 note that any verbose output is suppressed in this mode and must instead
331 be enabled explicitly (e.g., by using the option
338 variable and thus inhibit initial display of message headers when
339 reading mail or editing a mail folder.
343 Standard flag that inhibits reading the system wide
348 allows more control over the startup sequence; also see
349 .Sx "Resource files" .
353 Initialize the message body with the contents of the specified file,
354 which may be standard input
356 only in non-interactive context.
357 May be given in send mode only.
361 Any folder opened will be in read-only mode.
367 is a valid address then it specifies the envelope sender address to be
370 when a message is send.
373 include a user name, comments etc., then the components will be
374 separated and the name part will be passed to the MTA individually via
378 will also be assigned to the
380 variable, just as if additionally
382 had been specified (therefore affecting SMTP data transfer, too).
384 If instead an empty string is passed as
386 then the content of the variable
388 will be evaluated and used for this purpose whenever the MTA is
390 Note that \*(UA by default, without
392 that is, neither passes
396 flags to the MTA by itself.
399 .It Fl S Ar variable Ns Op = Ns value
400 Sets the internal option
402 and, in case of a value option, assigns
405 Even though variables set via
407 may be overwritten from within resource files,
408 the command line setting will be reestablished after all resource files
413 Specify the subject of the to-be-sent message.
417 The message given (on standard input) is expected to contain, separated
418 from the message body with an empty line, a message header with
423 fields giving its recipients, which will be added to those given on the
425 If a message subject is specified via
427 then it'll be used in favour of one given on the command line.
436 Note you can also specify
440 and the envelope address possibly specified with the option
443 The following, which are normally created automatically based
444 upon the message context, can also be specified:
449 .Ql Mail-Followup-To:
450 (special address massage will however still occur for the latter).
451 In fact custom header fields may also be used, the content of which
452 is passed through unchanged.
456 can be embedded, too.
460 Read the system mailbox of
462 (appropriate privileges presumed), and
465 in some aspects, e.g. in respect to
474 Show \*(UA's version and exit.
480 option enables display of some informational context messages.
481 Using it twice increases the level of verbosity.
487 to the list of commands to be executed before normal operation starts.
491 .Va batch-exit-on-error ;
492 the only possibility to execute commands in non-interactive mode when
493 reading startup files is actively prohibited.
499 even if not in interactive mode.
500 This can be used to, e.g., automatically format the composed message
501 text before sending the message:
502 .Bd -literal -offset indent
503 $ ( echo 'line one. Word. Word2.'; \e
504 echo '~| /usr/bin/fmt -tuw66' ) |\e
505 LC_ALL=C \*(uA -:/ -d~ bob@exam.ple
511 In batch mode the full set of commands is available, just like in
512 interactive mode, and diverse variable settings and internal states are
513 adjusted for batch necessities, e.g., it sets
524 also no initial header listing will be printed, and processing of
526 is enabled in compose mode.
527 The following prepares an email message in a batched dry run:
528 .Bd -literal -offset indent
529 $ LC_ALL=C printf 'm bob\en~s ubject\enText\en~.\enx\en' | \e
530 LC_ALL=C \*(uA -:/ -d#
535 This flag forces termination of option processing in order to prevent
538 It also forcefully puts \*(UA into send mode, see
539 .Sx "On sending mail, and non-interactive mode" .
543 In the above list of supported command line options,
547 are implemented by means of setting the respective option, as via
550 .Op Ar mta-option ...
552 arguments that are given at the end of the command line after a
554 separator will be passed through to the mail-transfer-agent (MTA) and
555 persist for an entire (interactive) session \(en if the setting of
557 allows their recognition;
558 MTA arguments can also be specified in the variable
559 .Va sendmail-arguments ;
560 find MTA interaction described in more detail in the documentation of
562 MTA arguments are ignored when mail is send via SMTP data transfer.
565 .\" .Ss "A starter" {{{
568 \*(UA is a direct descendant of
570 Mail, a successor of the Research
573 .Dq was there from the start
578 Mail reference manual begins with the following words:
580 .Bd -ragged -offset indent
581 Mail provides a simple and friendly environment for sending and
583 It divides incoming mail into its constituent messages and allows the
584 user to deal with them in any order.
585 In addition, it provides a set of
587 -like commands for manipulating messages and sending mail.
588 Mail offers the user simple editing capabilities to ease the composition
589 of outgoing messages, as well as providing the ability to define and
590 send to names which address groups of users.
594 \*(UA is thus the user side of the
596 mail system, whereas the system side (mail-transfer-agent, MTA) was
597 traditionally taken by
603 are often used for this purpose instead.
604 If the \*(OPal SMTP is included in the
606 of \*(UA then the system side is not a mandatory precondition for mail
610 Because \*(UA strives for compliance with POSIX
612 it is likely that some configuration settings have to be adjusted before
613 using it is a smooth experience.
616 file already bends those standard settings a bit towards more user
617 friendliness and safety, e.g., it sets the
621 variables in order to suppress the automatic moving of messages to
623 that would otherwise occur (see
624 .Sx "Message states" )
627 to not remove empty files in order not to mangle file permissions when
628 files eventually get recreated.
631 option so that by default file grouping (via the
633 prefix as documented also for
638 contains some further suggestions.
641 .\" .Ss "On sending mail, and non-interactive mode" {{{
642 .Ss "On sending mail, and non-interactive mode"
644 To send a message to one or more people, using a local
645 mail-transfer-agent (MTA; the executable path can be set via
647 or the \*(OPal builtin SMTP (set and see the variable
649 transport to actually deliver the generated mail message, \*(UA can be
650 invoked with arguments which are the names of people to whom the mail
653 .Bd -literal -offset indent
654 $ \*(uA -s ubject -a ttach.txt bill@exam.ple 'Bob <bob@exam.ple>'
655 # But... try it in an isolated dry-run mode first
656 $ LC_ALL=C \*(uA -:/ -d -vv -Sfrom="me <he@exam.ple>" \e
657 -b bcc@exam.ple -c cc@exam.ple \e
658 -s Subject -. "(Lovely) Bob <bob@exam.ple>"
662 The command line options
666 can be used to add (blind) carbon copy receivers.
667 Almost always lists of addresses can be given where an address is
669 whereas comma-separated lists should be given, e.g.,
670 .Ql -c """r1@exam.ple , r2@exam.ple,r3@exam.ple""" ,
671 that very example could also be given as the whitespace-separated list
672 .Ql -c """r1@exam.ple r2@exam.ple r3@exam.ple""" ,
673 but which for obvious reasons would not work for
674 .Ql -c """R1 <r1@exam.ple>, R2 (heh!) <r2@exam.ple>""" .
677 The user is then expected to type in the message contents.
678 In this compose mode \*(UA treats lines beginning with the character
680 special \(en these are so-called
682 which can be used to read in files, process shell commands, add and edit
683 attachments and more; e.g., the tilde escape
685 will start the text editor to revise the message in it's current state,
687 allows editing of the message recipients and
689 gives an overview of available tilde escapes.
693 at the beginning of an empty line leaves compose mode and causes the
694 message to be sent, whereas typing
697 twice will abort the current letter (saving its contents in the file
705 A number of variables can be used to alter default behavior; e.g.,
710 will automatically startup a text editor when compose mode is entered,
712 will cause the user to be prompted actively for carbon-copy recipients
715 option will allow leaving compose mode by writing a line consisting
720 Very important, though, is to define which
722 may be used when sending messages, usually by setting the option
725 having read the section
726 .Sx "The mime.types files"
727 to understand how the MIME-type of outgoing attachments is classified
728 and the knowledge that messages are sent asynchronously unless
730 is set: only with it MTA delivery errors will be recognizable.
735 is often necessary (e.g., in conjunction with
737 or desirable, you may want to do some dry-run tests before you go.
738 Saving a copy of the sent messages in a
740 may also be desirable \(en as for most mailbox file targets some
741 special conventions are recognized, see the
743 command for more on that.
745 .Sx "On URL syntax and credential lookup"
746 will spread some light on the
748 variable chains as well as on using URLs for accessing protocol-specific
753 contains an example configuration for sending messages via some of the
754 well-known public mail providers;
755 note it also gives a compact overview on how to setup a secure SSL/TLS
759 Message recipients (as specified on the command line or defined in
764 may not only be email addressees but can also be names of mailboxes and
765 even complete shell command pipe specifications.
766 Proper (shell) quoting is necessary, e.g., to embed whitespace characters.
767 (Recall that \*(UA deals with mail standards, therefore those define the
768 rules with which content is interpreted.)
771 is not set then only network addresses (see
773 for a description of mail addresses) and plain user names (including MTA
774 aliases) may be used, other types will be filtered out, giving a warning
777 .\" When changing any of the following adjust any RECIPIENTADDRSPEC;
778 .\" grep the latter for the complete picture
782 is set then extended recipient addresses will optionally be accepted:
783 Any name which starts with a vertical bar
785 character specifies a command pipe \(en the command string following the
787 is executed and the message is sent to its standard input;
788 Likewise, any name that starts with the character slash
790 or the character sequence dot slash
792 is treated as a file, regardless of the remaining content.
793 Any other name which contains an at sign
795 character is treated as a network address;
796 Any other name which starts with a plus sign
798 character specifies a mailbox name;
799 Any other name which contains a slash
801 character but no exclamation mark
805 character before also specifies a mailbox name;
806 What remains is treated as a network address.
808 .Bd -literal -offset indent
809 $ echo bla | \*(uA -Sexpandaddr -s test ./mbox.mbox
810 $ echo bla | \*(uA -Sexpandaddr -s test '|cat >> ./mbox.mbox'
811 $ echo safe | LC_ALL=C \e
812 \*(uA -:/ -Sv15-compat -Ssendwait -Snosave \e
813 -Sexpandaddr=fail,-all,+addr -s test \e
818 It is possible to create personal distribution lists via the
820 command, so that, for instance, the user can send mail to
822 and have it go to a group of people:
825 .Dl alias cohorts bill jkf mark kridle@ucbcory ~/mail/cohorts.mbox
828 Please note that this mechanism has nothing in common with the system
829 wide aliases that may be used by the local MTA (mail-transfer-agent),
830 which are subject to the
834 and are often tracked in a file
840 Personal aliases will be expanded by \*(UA before the message is sent,
841 and are thus a convenient alternative to specifying each addressee by
845 To avoid environmental noise scripts should
847 \*(UA from any configuration files and create a script-local
848 environment, ideally with the command line options
850 to disable any configuration file in conjunction with repititions of
852 to specify variables:
854 .Bd -literal -offset indent
855 $ env LC_ALL=C password=NOTSECRET \e
856 \*(uA -:/ -Sv15-compat -Ssendwait -Snosave \e
857 -Sexpandaddr=fail,-all,+addr \e
858 -S 'smtp=smtps://mylogin@exam.ple:465' -Ssmtp-auth=login \e
859 -S 'from=scriptreply@exam.ple' \e
860 -s 'subject' -a attachment_file \e
861 -. "Recipient 1 <rec1@exam.ple>" rec2@exam.ple \e
866 In interactive mode, which is introduced in the next section, messages
867 can be sent by calling the
869 command with a list of recipient addresses \(em the semantics are
870 completely identical to non-interactive message sending, except that
871 it is likely necessary to separate recipient lists with commas:
873 .Bd -literal -offset indent
874 $ \*(uA -d -Squiet -Semptystart
875 "/var/spool/mail/user": 0 messages
876 ? mail "Recipient 1 <rec1@exam.ple>", rec2@exam.ple
877 ? # Will do the right thing (tm)
878 ? m rec1@exam.ple rec2@exam.ple
882 .\" .Ss "On reading mail, and interactive mode" {{{
883 .Ss "On reading mail, and interactive mode"
885 When invoked without addressees \*(UA enters interactive mode in which
887 When used like that the user's system mailbox (see the command
889 for an in-depth description of the different mailbox types that exist)
890 is read in and a one line header of each message therein is displayed.
891 The visual style of this summary of
893 can be adjusted through the variable
895 and the possible sorting criterion via
897 If the initially opened mailbox is empty \*(UA will instead exit
898 immediately (after displaying a message) unless the variable
907 will give a listing of all available commands and
909 will give a summary of some common ones.
910 If the \*(OPal documentation strings are available one can type
912 and see the actual expansion of
914 and what it's purpose is, i.e., commands can be abbreviated
915 (note that POSIX defines some abbreviations, so that the alphabetical
916 order of commands doesn't necessarily relate to the abbreviations; it is
917 possible to define overwrites with the
922 Messages are given numbers (starting at 1) which uniquely identify
923 messages; the current message \(en the
925 \(en will either be the first new message, or the first unread message,
926 or the first message of the mailbox; the option
928 will instead cause usage of the last message for this purpose.
933 ful of header summaries containing the
937 will display only the summaries of the given messages, defaulting to the
941 Messages can be displayed on the user's terminal with the
945 By default the current message
947 is displayed, but like with many other commands it is possible to give
948 a fancy message specification (see
949 .Sx "Specifying messages" ) ,
952 will display all unread messages,
957 will type the messages 1 and 5,
959 will type the messages 1 through 5, and
963 will display the last and the next message, respectively.
966 (a more substantial alias of the standard command
968 will display a header summary of the given message specification list
969 instead of their content, e.g., the following will search for subjects:
972 .Dl ? from """@Some subject to search for"""
975 In the default setup all header fields of a message will be displayed,
976 but this can be changed: either by blacklisting a list of fields via
978 or by whitelisting only a given list with the
981 .Ql Ic \:retain Ns \0date from to cc subject .
982 In order to display all header fields of a message regardless of
983 currently active ignore or retain lists, use the command
987 controls wether and when \*(UA will use the configured
989 for display instead of directly writing to the user terminal
990 (generally speaking).
991 Note that historically the global
993 not only adjusts the list of displayed headers, but also sets
997 Dependent upon the configuration a line editor (see the section
998 .Sx "On terminal control and line editor" )
999 aims at making user experience with the many
1002 When reading the system mailbox or when
1006 specified a mailbox explicitly prefixed with the special
1008 modifier (propagating the mailbox to a primary one) then messages which
1009 have been read will be moved to a secondary mailbox, the user's
1011 file, automatically when the mailbox is left, either by changing the
1012 active mailbox or by quitting \*(UA (also see
1013 .Sx "Message states" )
1014 \(en this automatic moving from a system or primary to the secondary
1015 mailbox is not performed when the variable
1020 After examining a message the user can also
1024 to the sender and all recipients or
1026 exclusively to the sender(s).
1027 Messages can also be
1029 ed (shorter alias is
1031 Note that when replying to or forwarding a message recipient addresses
1032 will be stripped from comments and names unless the option
1035 Deletion causes \*(UA to forget about the message;
1036 This is not irreversible, though, one can
1038 the message by giving its number,
1039 or the \*(UA session can be ended by giving the
1044 To end a mail processing session one may either issue
1046 to cause a full program exit, which possibly includes
1047 automatic moving of read messages to
1049 as well as updating the \*(OPal line editor
1053 instead in order to prevent any of these actions.
1056 .\" .Ss "HTML mail and MIME attachments" {{{
1057 .Ss "HTML mail and MIME attachments"
1059 Messages which are HTML-only get more and more common and of course many
1060 messages come bundled with a bouquet of MIME attachments.
1061 Whereas \*(UA \*(OPally supports a simple HTML-to-text converter to deal
1062 with HTML messages (see
1063 .Sx "The mime.types files" ) ,
1064 it normally can't deal with any of these itself, but instead programs
1065 need to become registered to deal with specific MIME types or file
1067 These programs may either prepare plain text versions of their input
1068 in order to enable \*(UA to display the content on the terminal,
1069 or display the content themselves, for example in a graphical window.
1072 To install an external handler program for a specific MIME type set an
1074 .Va pipe-TYPE/SUBTYPE
1075 variable; to instead define a handler for a specific file extension set
1078 variable \(en these handlers take precedence.
1079 \*(OPally \*(UA supports mail user agent configuration as defined in
1080 RFC 1524; this mechanism, documented in the section
1081 .Sx "The Mailcap files" ,
1082 will be queried for display or quote handlers if none of the former two
1083 .\" TODO v15-compat "will be" -> "is"
1084 did; it will be the sole source for handlers of other purpose.
1085 A last source for handlers may be the MIME type definition itself, if
1086 the \*(UA specific type-marker extension was used when defining the type
1089 (Many of the builtin MIME types do so by default.)
1093 .Va mime-counter-evidence
1094 can be set to improve dealing with faulty MIME part declarations as are
1095 often seen in real-life messages.
1096 E.g., to display a HTML message inline (that is, converted to a more
1097 fancy plain text representation than the builtin converter is capable to
1098 produce) with either of the text-mode browsers
1102 teach \*(UA about MathML documents and make it display them as plain
1103 text, and to open PDF attachments in an external PDF viewer,
1104 asynchronously and with some other magic attached:
1106 .Bd -literal -offset indent
1107 if $features !@ HTML-FILTER
1108 #set pipe-text/html="elinks -force-html -dump 1"
1109 set pipe-text/html="lynx -stdin -dump -force_html"
1110 # Display HTML as plain text instead
1111 #set pipe-text/html=@
1113 mimetype '@ application/mathml+xml mathml'
1114 set pipe-application/pdf="@&=@ \e
1115 trap \e"rm -f \e\e\e"${NAIL_FILENAME_TEMPORARY}\e\e\e"\e" EXIT;\e
1116 trap \e"trap \e\e\e"\e\e\e" INT QUIT TERM; exit 1\e" \e INT QUIT TERM;\e
1117 xpdf \e"${NAIL_FILENAME_TEMPORARY}\e""
1121 Note: special care must be taken when using such commands as mail
1122 viruses may be distributed by this method: if messages of type
1123 .Ql application/x-sh
1124 or files with the extension
1126 were blindly filtered through the shell, for example, a message sender
1127 could easily execute arbitrary code on the system \*(UA is running on.
1128 For more on MIME, also in respect to sending of messages, see the
1130 .Sx "The mime.types files" ,
1131 .Sx "The Mailcap files"
1136 .\" .Ss "Mailing lists" {{{
1139 \*(UA offers some support to ease handling of mailing lists.
1142 promotes all given arguments to known mailing lists, and
1144 sets their subscription attribute, creating them first as necessary.
1149 automatically, but only resets the subscription attribute.)
1150 Using the commands without arguments will show (a subset of) all
1151 currently defined mailing lists.
1156 can be used to mark out messages with configured list addresses
1157 in the header display.
1160 \*(OPally mailing lists may also be specified as (extended) regular
1161 expressions, which allows matching of many addresses with a single
1163 However, all fully qualified list addresses are matched via a fast
1164 dictionary, whereas expressions are placed in (a) list(s) which is
1165 (are) matched sequentially.
1167 .Bd -literal -offset indent
1168 set followup-to followup-to-honour=ask-yes reply-to-honour=ask-yes
1169 mlist a1@b1\e.c1 a2@b2\e.c2 .*@lists\e.c3$
1170 mlsubscribe a4@b4\e.c4 exact@lists\e.c3
1175 .Va followup-to-honour
1177 .Ql Mail-\:Followup-\:To:
1178 header is honoured when the message is being replied to (via
1184 controls wether this header is created when sending mails; it will be
1185 created automatically for a couple of reasons, too, like when the
1187 .Dq mailing list specific
1192 is used to respond to a message with its
1193 .Ql Mail-Followup-To:
1197 A difference in between the handling of known and subscribed lists is
1198 that the address of the sender is usually not part of a generated
1199 .Ql Mail-Followup-To:
1200 when addressing the latter, whereas it is for the former kind of lists.
1201 Usually because there are exceptions: say, if multiple lists are
1202 addressed and not all of them are subscribed lists.
1204 For convenience \*(UA will, temporarily, automatically add a list
1205 address that is presented in the
1207 header of a message that is being responded to to the list of known
1209 Shall that header have existed \*(UA will instead, dependend on the
1211 .Va reply-to-honour ,
1214 for this purpose in order to accept a list administrators' wish that
1215 is supposed to have been manifested like that (but only if it provides
1216 a single address which resides on the same domain as what is stated in
1220 .\" .Ss "Resource files" {{{
1221 .Ss "Resource files"
1223 Upon startup \*(UA reads in several resource files:
1225 .Bl -tag -width ".It Pa _AIL_EXTRA_R_"
1228 System wide initialization file.
1229 Reading of this file can be suppressed, either by using the
1233 command line options, or by setting the environment variable
1234 .Ev NAIL_NO_SYSTEM_RC .
1238 File giving initial commands.
1239 A different file can be chosen by setting the environment variable
1241 Reading of this file can be suppressed with the
1243 command line option.
1245 .It Va NAIL_EXTRA_RC
1246 Can be used to define an optional startup file to be read after all
1247 other resource files.
1248 It can be used to specify settings that are not understood by other
1250 implementations, for example.
1251 This variable is only honoured when defined in a resource file.
1255 The content of these files is interpreted as follows:
1258 .Bl -bullet -compact
1260 A lines' leading whitespace is removed.
1262 Empty lines are ignored.
1264 Any other line is interpreted as a command.
1265 It may be spread over multiple input lines if the newline character is
1267 by placing a backslash character
1269 as the last character of the line; whereas any leading whitespace of
1270 follow lines is ignored, trailing whitespace before a escaped newline
1271 remains in the input.
1273 If the line (content) starts with the number sign
1275 then it is a comment-command \(en a real command! \(en and also ignored.
1276 This command is the only form of comment that is understood.
1280 Unless \*(UA is about to enter interactive mode syntax errors that occur
1281 while loading these files are treated as errors and cause program exit.
1282 More files with syntactically equal content can be
1284 The following, saved in a file, would be an examplary content:
1286 .Bd -literal -offset indent
1287 # This line is a comment command. And y\e
1288 es, it is really continued here.
1295 .\" .Ss "Character sets" {{{
1296 .Ss "Character sets"
1298 \*(OP \*(UA detects the character set of the terminal by using
1299 mechanisms that are controlled by the
1304 should give an overview); the \*(UA internal variable
1306 will be set to the detected terminal character set accordingly
1307 and will thus show up in the output of the commands
1313 However, a user supplied
1315 value is not overwritten by this detection mechanism: this
1317 must be used if the detection doesn't work properly,
1318 and it may be used to adjust the name of the locale character set.
1319 E.g., on BSD systems one may use a locale with the character set
1320 ISO8859-1, which is not a valid name for this character set; to be on
1321 the safe side, one may set
1323 to the correct name, which is ISO-8859-1.
1326 Note that changing the value doesn't mean much beside that,
1327 since several aspects of the real character set are implied by the
1328 locale environment of the system,
1329 and that stays unaffected by the content of an overwritten
1332 (This is mostly an issue when interactively using \*(UA, though.
1333 It is actually possible to send mail in a completely
1335 locale environment, an option that \*(UA's test-suite uses excessively.)
1338 If no character set conversion capabilities have been compiled into
1341 doesn't include the term
1345 will be the only supported character set,
1346 it is simply assumed that it can be used to exchange 8-bit messages,
1347 and the rest of this section does not apply;
1348 it may however still be necessary to explicitly set it if automatic
1349 detection fails, since in that case it defaults to the mentioned
1350 .\" (Keep in SYNC: ./nail.1:"Character sets", ./nail.h:CHARSET_*!)
1354 When reading messages, their text is converted into
1356 as necessary in order to display them on the users terminal.
1357 Unprintable characters and invalid byte sequences are detected
1358 and replaced by proper substitution characters (unless the variable
1360 was set once \*(UA was started).
1362 .Va charset-unknown-8bit
1363 to deal with another hairy aspect of message interpretation.
1366 When sending messages all their parts and attachments are classified.
1367 Whereas no character set conversion is performed on those parts which
1368 appear to be binary data,
1369 the character set being used must be declared within the MIME header of
1370 an outgoing text part if it contains characters that do not conform to
1371 the set of characters that are allowed by the email standards.
1372 Permissible values for character sets can be declared using the
1376 which defines a catch-all last-resort fallback character set that is
1377 implicitly appended to the list of character-sets in
1381 When replying to a message and the variable
1382 .Va reply-in-same-charset
1383 is set then the character set of the message being replied to is tried
1385 And it is also possible to make \*(UA work even more closely related to
1386 the current locale setting automatically by using the variable
1387 .Va sendcharsets-else-ttycharset ,
1388 please see there for more information.
1391 All the specified character sets are tried in order unless the
1392 conversion of the part or attachment succeeds.
1393 If none of the tried (8-bit) character sets is capable to represent the
1394 content of the part or attachment,
1395 then the message will not be sent and its text will optionally be
1399 In general, if the message
1400 .Dq Cannot convert from a to b
1401 appears, either some characters are not appropriate for the currently
1402 selected (terminal) character set,
1403 or the needed conversion is not supported by the system.
1404 In the first case, it is necessary to set an appropriate
1406 locale and/or the variable
1410 The best results are usually achieved when \*(UA is run in a UTF-8
1411 locale on a UTF-8 capable terminal, in which case the full Unicode
1412 spectrum of characters is available.
1413 In this setup characters from various countries can be displayed,
1414 while it is still possible to use more simple character sets for sending
1415 to retain maximum compatibility with older mail clients.
1418 On the other hand the POSIX standard defines a locale-independent 7-bit
1419 .Dq portable character set
1420 that should be used when overall portability is an issue, the even more
1421 restricted subset named
1422 .Dq portable filename character set
1423 consisting of A-Z, a-z, 0-9, period
1432 .\" .Ss "Message states" {{{
1433 .Ss "Message states"
1435 \*(UA differentiates in between several different message states;
1436 the current state will be reflected in header summary displays if
1438 is configured to do so (via the internal variable
1440 and messages can also be selected and be acted upon depending on their
1442 .Sx "Specifying messages" ) .
1443 When operating on the system mailbox or in primary mailboxes opened with
1448 special actions, like the automatic moving of messages to the secondary
1450 mailbox may be applied when the mailbox is left (also implicitly via
1451 a successful exit of \*(UA, but not if the special command
1453 is used) \(en however, because this may be irritating to users which
1456 mail-user-agents, the default global
1462 variables in order to suppress this behaviour.
1464 .Bl -tag -width ".It Ql _reserved"
1466 Message has neither been viewed nor moved to any other state.
1467 Such messages are retained even in the system mailbox.
1470 Message has neither been viewed nor moved to any other state, but the
1471 message was present already when the mailbox has been opened last:
1472 Such messages are retained even in the system mailbox.
1475 The message has been processed by one of the following commands:
1495 commands may also cause the next message to be marked as read, depending
1501 command is used, messages that are in the system mailbox or in mailboxes
1502 which were opened with the special
1506 state when the mailbox is left will be saved in
1513 The message has been processed by one of the following commands:
1519 can be used to access such messages.
1522 The message has been processed by a
1524 command and it will be retained in its current location.
1527 The message has been processed by one of the following commands:
1533 command is used, messages that are in the system mailbox or in mailboxes
1534 which were opened with the special
1538 state when the mailbox is left will be deleted; they will be saved in
1546 .\" .Ss "Specifying messages" {{{
1547 .Ss "Specifying messages"
1554 can be given a list of message numbers as arguments to apply to a number
1555 of messages at once.
1558 deletes messages 1 and 2,
1561 will delete the messages 1 through 5.
1562 In sorted or threaded mode (see the
1566 will delete the messages that are located between (and including)
1567 messages 1 through 5 in the sorted/threaded order, as shown in the
1570 Multiple colon modifiers can be joined into one, e.g.,
1572 The following special message names exist:
1574 .Bl -tag -width ".It Ar _n_u"
1580 All old messages (any not in state
1605 All answered messages
1610 All messages marked as draft.
1612 \*(OP All messages classified as spam.
1614 \*(OP All messages with unsure spam classification.
1616 The current message, the so-called
1619 The message that was previously the current message.
1621 The parent message of the current message,
1622 that is the message with the Message-ID given in the
1624 field or the last entry of the
1626 field of the current message.
1628 The next previous undeleted message,
1629 or the next previous deleted message for the
1632 In sorted/threaded mode,
1633 the next previous such message in the sorted/threaded order.
1635 The next undeleted message,
1636 or the next deleted message for the
1639 In sorted/threaded mode,
1640 the next such message in the sorted/threaded order.
1642 The first undeleted message,
1643 or the first deleted message for the
1646 In sorted/threaded mode,
1647 the first such message in the sorted/threaded order.
1650 In sorted/threaded mode,
1651 the last message in the sorted/threaded order.
1655 selects the message addressed with
1659 is any other message specification,
1660 and all messages from the thread that begins at it.
1661 Otherwise it is identical to
1666 the thread beginning with the current message is selected.
1671 All messages that were included in the message list for the previous
1674 .It Ar / Ns Ar string
1675 All messages that contain
1677 in the subject field (case ignored).
1684 the string from the previous specification of that type is used again.
1686 .It Xo Op Ar @ Ns Ar name-list Ns
1689 All messages that contain the given case-insensitive search
1691 ession; if the \*(OPal regular expression (see
1693 support is available
1695 will be interpreted as (an extended) one if any of the
1697 (extended) regular expression characters is seen.
1699 .Ar @ Ns Ar name-list
1700 part is missing, the search is restricted to the subject field body,
1703 specifies a comma-separated list of header fields to search, as in
1705 .Dl '@to,from,cc@Someone i ought to know'
1707 In order to search for a string that includes a
1709 (commercial at) character the
1711 is effectively non-optional, but may be given as the empty string.
1712 Some special header fields may be abbreviated:
1726 respectively and case-insensitively.
1731 can be used to search in (all of) the header(s) of the message, and the
1740 can be used to perform full text searches \(en whereas the former
1741 searches only the body, the latter also searches the message header.
1743 This message specification performs full text comparison, but even with
1744 regular expression support it is almost impossible to write a search
1745 expression that savely matches only a specific address domain.
1746 To request that the content of the header is treated as a list of
1747 addresses, and to strip those down to the plain email address which the
1748 search expression is to be matched against, prefix the header name
1749 (abbreviation) with a tilde
1752 .Dl @~f@@a\e.safe\e.domain\e.match$
1756 .Dq any substring matches
1759 header, which will match addresses (too) even if
1761 is set (and POSIX says
1762 .Dq any address as shown in a header summary shall be matchable in this form ) ;
1765 variable is set, only the local part of the address is evaluated
1766 for the comparison, not ignoring case, and the setting of
1768 is completely ignored.
1769 For finer control and match boundaries use the
1771 search expression; the \*(OPal IMAP-style
1773 expression can also be used if substring matches are desired.
1777 \*(OP IMAP-style SEARCH expressions may also be used.
1778 This addressing mode is available with all types of folders;
1779 \*(UA will perform the search locally as necessary.
1780 Strings must be enclosed by double quotes
1782 in their entirety if they contain white space or parentheses;
1783 within the quotes, only backslash
1785 is recognized as an escape character.
1786 All string searches are case-insensitive.
1787 When the description indicates that the
1789 representation of an address field is used,
1790 this means that the search string is checked against both a list
1793 .Bd -literal -offset indent
1794 (\*qname\*q \*qsource\*q \*qlocal-part\*q \*qdomain-part\*q)
1799 and the addresses without real names from the respective header field.
1800 These search expressions can be nested using parentheses, see below for
1804 .Bl -tag -compact -width ".It Ar _n_u"
1805 .It Ar ( criterion )
1806 All messages that satisfy the given
1808 .It Ar ( criterion1 criterion2 ... criterionN )
1809 All messages that satisfy all of the given criteria.
1811 .It Ar ( or criterion1 criterion2 )
1812 All messages that satisfy either
1817 To connect more than two criteria using
1819 specifications have to be nested using additional parentheses,
1821 .Ql (or a (or b c)) ,
1825 .Ql ((a or b) and c) .
1828 operation of independent criteria on the lowest nesting level,
1829 it is possible to achieve similar effects by using three separate
1833 .It Ar ( not criterion )
1834 All messages that do not satisfy
1836 .It Ar ( bcc \*q Ns Ar string Ns Ar \*q )
1837 All messages that contain
1839 in the envelope representation of the
1842 .It Ar ( cc \*q Ns Ar string Ns Ar \*q )
1843 All messages that contain
1845 in the envelope representation of the
1848 .It Ar ( from \*q Ns Ar string Ns Ar \*q )
1849 All messages that contain
1851 in the envelope representation of the
1854 .It Ar ( subject \*q Ns Ar string Ns Ar \*q )
1855 All messages that contain
1860 .It Ar ( to \*q Ns Ar string Ns Ar \*q )
1861 All messages that contain
1863 in the envelope representation of the
1866 .It Ar ( header name \*q Ns Ar string Ns Ar \*q )
1867 All messages that contain
1872 .It Ar ( body \*q Ns Ar string Ns Ar \*q )
1873 All messages that contain
1876 .It Ar ( text \*q Ns Ar string Ns Ar \*q )
1877 All messages that contain
1879 in their header or body.
1880 .It Ar ( larger size )
1881 All messages that are larger than
1884 .It Ar ( smaller size )
1885 All messages that are smaller than
1889 .It Ar ( before date )
1890 All messages that were received before
1892 which must be in the form
1896 denotes the day of the month as one or two digits,
1898 is the name of the month \(en one of
1899 .Ql Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ,
1902 is the year as four digits, e.g.,
1906 All messages that were received on the specified date.
1907 .It Ar ( since date )
1908 All messages that were received since the specified date.
1909 .It Ar ( sentbefore date )
1910 All messages that were sent on the specified date.
1911 .It Ar ( senton date )
1912 All messages that were sent on the specified date.
1913 .It Ar ( sentsince date )
1914 All messages that were sent since the specified date.
1916 The same criterion as for the previous search.
1917 This specification cannot be used as part of another criterion.
1918 If the previous command line contained more than one independent
1919 criterion then the last of those criteria is used.
1923 .\" .Ss "On URL syntax and credential lookup" {{{
1924 .Ss "On URL syntax and credential lookup"
1926 \*(IN For accessing protocol-specific resources usage of Uniform
1927 Resource Locators (URL, RFC 1738) has become omnipresent.
1928 \*(UA expects and understands URLs in the following form;
1931 denote optional parts, optional either because there also exist other
1932 ways to define the information in question or because support of the
1933 part is protocol-specific (e.g.,
1935 is used by the IMAP protocol but not by POP3);
1940 are specified they must be given in URL percent encoded form (RFC 3986;
1948 .Dl PROTOCOL://[USER[:PASSWORD]@]server[:port][/path]
1951 Note that these \*(UA URLs most often don't conform to any real
1952 standard, but instead represent a normalized variant of RFC 1738 \(en
1953 they are not used in data exchange but only ment as a compact,
1954 easy-to-use way of defining and representing information in
1955 a well-known notation.
1958 Many internal variables of \*(UA exist in multiple versions, called
1959 variable chains for the rest of this document: the plain
1964 .Ql variable-USER@HOST .
1971 had been specified in the respective URL, otherwise it refers to the plain
1977 that had been found when doing the user chain lookup as is described
1980 will never be in URL percent encoded form, wether it came from an URL or
1981 not; i.e., values of
1982 .Sx "INTERNAL VARIABLES"
1983 must not be URL percent encoded.
1986 For example, wether an hypothetical URL
1987 .Ql smtp://hey%3Ayou@our.house
1988 had been given that includes a user, or wether the URL was
1989 .Ql smtp://our.house
1990 and the user had been found differently, to lookup the variable chain
1991 .Va smtp-use-starttls
1992 \*(UA first looks for wether
1993 .Ql smtp-\:use-\:starttls-\:hey:you@our.house
1994 is defined, then wether
1995 .Ql smtp-\:use-\:starttls-\:our.house
1996 exists before finally ending up looking at the plain variable itself.
1999 \*(UA obeys the following logic scheme when dealing with the
2000 necessary credential informations of an account:
2006 has been given in the URL the variables
2010 are looked up; if no such variable(s) can be found then \*(UA will,
2011 when enforced by the \*(OPal variables
2012 .Va netrc-lookup-HOST
2019 specific entry which provides a
2021 name: this lookup will only succeed if unambiguous (one possible matching
2025 If there is still no
2027 then \*(UA will fall back to the user who is supposed to run \*(UA:
2028 either the name that has been given with the
2030 command line option (or, equivalently, but with less precedence, the
2031 environment variable
2036 The identity of this user has been fixated during \*(UA startup and is
2037 known to be a valid user on the current host.
2040 Authentication: unless otherwise noted this will lookup the
2041 .Va PROTOCOL-auth-USER@HOST , PROTOCOL-auth-HOST , PROTOCOL-auth
2042 variable chain, falling back to a protocol-specific default should this
2048 has been given in the URL, then if the
2050 has been found through the \*(OPal
2052 then that may have already provided the password, too.
2053 Otherwise the variable chain
2054 .Va password-USER@HOST , password-HOST , password
2055 is looked up and used if existent.
2057 \*(OP Then if any of the variables of the chain
2058 .Va agent-shell-lookup-USER@HOST , agent-shell-lookup-HOST , \
2060 is set the shell command specified therein is run and the output (less
2061 newline characters) will be used as the password.
2062 It is perfectly valid for such an agent to simply not return any data,
2063 in which case the password lookup is continued somewhere else;
2064 Any command failure is treated as a hard error, however.
2066 Afterwards the complete \*(OPal variable chain
2067 .Va netrc-lookup-USER@HOST , netrc-lookup-HOST , netrc-lookup
2071 cache is searched for a password only (multiple user accounts for
2072 a single machine may exist as well as a fallback entry without user
2073 but with a password).
2075 If at that point there is still no password available, but the
2076 (protocols') chosen authentication type requires a password, then in
2077 interactive mode the user will be prompted on the terminal.
2082 S/MIME verification works relative to the values found in the
2086 header field(s), which means that the values of
2087 .Va smime-sign , smime-sign-cert , smime-sign-include-certs
2089 .Va smime-sign-message-digest
2090 will not be looked up using the
2094 chains from above but instead use the corresponding values from the
2095 message that is being worked on.
2096 In unusual cases multiple and different
2100 combinations may therefore be involved \(en on the other hand those
2101 unusual cases become possible.
2102 The usual case is as short as:
2105 .Dl set smtp=smtp://USER:PASS@HOST smtp-use-starttls \e
2106 .Dl \ \ \ \ smime-sign smime-sign-cert=+smime.pair
2111 contains complete example configurations.
2114 .\" .Ss "On terminal control and line editor" {{{
2115 .Ss "On terminal control and line editor"
2117 \*(OP \*(UA can be configured to support a line editor,
2118 history lists that can be saved in between sessions,
2119 and terminal control to improve interactive usage experience.
2120 For the former one may either link against an external library
2121 .Pf ( Xr readline 3 ;
2122 behaviour of \*(UA may differ slightly),
2123 or enable the builtin Mailx-Line-Editor (MLE), which should work in all
2124 environments which comply to the ISO C standard
2126 and which will support wide glyphs if possible (the necessary
2127 functionality had been removed from ISO C, but was included in
2129 Prevent usage of a line editor in interactive mode by setting the
2131 .Va line-editor-disable .
2136 feature is available then input from line editor prompts will be saved
2137 in a history list that can be searched in and be expanded from.
2138 Such saving can be prevented by prefixing input with any amount of
2140 Aspects of history, like allowed content, maximum size etc., can be
2141 configured with the variables
2144 .Va history-gabby-persist
2149 \*(OP Terminal control will be realized through one of the standard
2151 libraries, either the
2153 or, alternatively, the
2155 both of which will be initialized to work with the environment variable
2157 Terminal control will enhance or enable interactive usage aspects, e.g.,
2158 .Sx "Coloured display" ,
2159 and extend behaviour of the MLE, which may learn the key-sequences of
2160 keys like the cursor and function keys, and which will automatically
2163 alternative screen shall the terminal support it.
2164 The internal variable
2166 can be used to overwrite settings or to learn (correct(ed)) keycodes.
2167 Actual interaction with the chosen library can be disabled completely by
2168 setting the internal variable
2169 .Va termcap-disable ,
2170 which may be necessary for proper operation on the actual terminal;
2172 will be queried regardless, even if the \*(OPal support for the
2173 libraries has not been enabled at configuration time.
2176 \*(OP The builtin \*(UA line editor MLE supports the following
2177 operations; the notation
2179 stands for the combination of the
2181 key plus the mentioned character, e.g.,
2184 .Dq hold down control key and press the A key .
2185 Especially without termcap support setting respective entries in
2187 will help shall the MLE misbehave.
2188 The MLE also supports several
2193 .Bl -tag -compact -width "Ql _M"
2195 Go to the start of the line.
2197 Move the cursor backward one character.
2199 Forward delete the character under the cursor;
2200 quits \*(UA if used on the empty line unless the
2204 Go to the end of the line.
2206 Move the cursor forward one character.
2209 Cancel current operation, full reset.
2210 If there is an active history search or tabulator expansion then this
2211 command will first reset that, reverting to the former line content;
2212 thus a second reset is needed for a full reset in this case.
2213 In all cases \*(UA will reset a possibly used multibyte character input
2219 backward delete one character.
2223 .Dq horizontal tabulator :
2224 try to expand the word before the cursor.
2226 .Dq tabulator-completion
2227 as is known from the
2229 but really means the usual \*(UA expansion, as documented for
2231 yet it involves shell expansion as a last step, too.)
2236 complete this line of input.
2238 Delete all characters from the cursor to the end of the line.
2242 \*(OP Go to the next history entry.
2247 \*(OP Go to the previous history entry.
2249 \*(OP Complete the current line from (the remaining older) history entries.
2256 Prompts for a Unicode character to be inserted.
2258 Delete the characters from the one preceding the cursor to the preceding
2261 Move the cursor forward one word boundary.
2263 Move the cursor backward one word boundary.
2267 If the keycodes are known then the left and right cursor keys will map to
2271 respectively, the up and down cursor keys will map to
2275 and the Home/End/PgUp/PgDown keys will call the
2277 command with the respective arguments
2283 (i.e., perform scrolling through the header summary list).
2284 Also the up and down cursor keys should invoke
2286 for up- and downwards movement if they are used while the
2291 .\" .Ss "Coloured display" {{{
2292 .Ss "Coloured display"
2294 \*(OP \*(UA can be configured to support a coloured display and font
2295 attributes by emitting ANSI / ISO 6429 SGR (select graphic rendition)
2297 Usage of colours and font attributes solely depends upon the
2298 capability of the detected terminal type that is defined by the
2299 environment variable
2301 and which can be fine-tuned by the user via the internal variable
2305 On top of what \*(UA knows about the terminal the boolean variable
2307 defines wether the actually applicable colour and font attribute
2308 sequences should also be generated when output is going to be paged
2309 through the external program defined by the environment variable
2314 This is not enabled by default because different pager programs need
2315 different command line switches or other configuration in order to
2316 support those sequences.
2317 \*(UA however knows about some widely used pagers and in a clean
2318 environment it is often enough to simply set
2320 please refer to that variable for more on this topic.
2325 is set then any active usage of colour and font attribute sequences
2326 is suppressed, but without affecting possibly established
2331 To define and control colours and font attributes a single multiplexer
2332 command family exists:
2334 shows or defines colour mappings for the given colour type (e.g.,
2337 can be used to remove mappings of a given colour type.
2338 Since colours are only available in interactive mode, it may make
2339 sense to conditionalize the colour setup by encapsulating it with
2342 .Bd -literal -offset indent
2343 if terminal && $features =@ +colour
2344 colour iso view-msginfo ft=bold,fg=green
2345 colour iso view-header ft=bold,fg=red "from,subject"
2346 colour iso view-header fg=red
2348 uncolour iso view-header from,subject
2349 colour iso view-header ft=bold,fg=magenta,bg=cyan
2350 colour 256 view-header ft=bold,fg=208,bg=230 subject,from
2351 colour mono view-header ft=bold
2352 colour mono view-header ft=bold,ft=reverse subject,from
2356 .\" }}} (DESCRIPTION)
2359 .\" .Sh COMMANDS {{{
2362 Each command is typed on a line by itself,
2363 and may take arguments following the command word.
2364 The command need not be typed in its entirety \(en
2365 the first command which matches the typed prefix is used.
2366 An \(en alphabetically \(en sorted list of commands can be shown
2373 when given an argument, will show a documentation string for the
2374 command matching the expanded argument, as in
2376 which should be a shorthand of
2378 documentation strings are however \*(OPal.
2381 For commands which take message lists as arguments, the next message
2382 forward that satisfies the command's requirements will be used shall no
2383 explicit message list have been specified.
2384 If there are no messages forward of the current message,
2385 the search proceeds backwards,
2386 and if there are no good messages at all,
2388 .Dq no applicable messages
2389 and aborts the command.
2390 The arguments to commands can be quoted, using the following methods:
2393 .Bl -bullet -compact -offset indent
2395 An argument can be enclosed between paired double-quotes
2400 any white space, shell word expansion, or backslash characters (except
2401 as described next) within the quotes are treated literally as part of
2403 A double-quote will be treated literally within single-quotes and vice
2405 Inside such a quoted string the actually used quote character can be
2406 used nonetheless by escaping it with a backslash
2412 An argument that is not enclosed in quotes, as above, can usually still
2413 contain space characters if those spaces are backslash-escaped, as in
2417 A backslash outside of the enclosing quotes is discarded
2418 and the following character is treated literally as part of the argument.
2421 An unquoted backslash at the end of a command line is discarded and the
2422 next line continues the command.
2426 Filenames, where expected, are subsequently subjected to the following
2427 transformations, in sequence:
2430 .Bl -bullet -compact -offset indent
2432 If the filename begins with an unquoted plus sign, and the
2434 variable is defined,
2435 the plus sign will be replaced by the value of the
2437 variable followed by a slash.
2440 variable is unset or is set to null, the filename will be unchanged.
2443 Shell word expansions are applied to the filename.
2444 .\" TODO shell word expansion shell expand fexpand FEXP_NSHELL
2445 .Sy Compatibility note:
2446 on the long run support for complete shell word expansion will be
2447 replaced by an internally implemented restricted expansion mechanism in
2448 order to circumvent possible security impacts through shell expansion.
2449 Expect that a growing number of program parts only support this
2452 Meta expansions are applied to the filename: leading tilde characters
2454 will be replaced by the expansion of
2456 and any occurrence of
2460 will be replaced by the expansion of the variable, if possible;
2461 \*(UA internal as well as environmental (shell) variables can be
2462 accessed through this mechanism.
2463 In order to include a raw
2465 character precede it with a backslash
2467 to include a backslash double it.
2468 If more than a single pathname results from this expansion and the
2469 command is expecting one file, an error results.
2471 Note that in interactive display context, in order to allow simple
2472 value acceptance (typing
2474 backslash quoting is performed automatically as necessary, e.g., a file
2475 .Ql diet\e is \ecurd.txt
2476 will be displayed as
2477 .Ql diet\e\e is \e\ecurd.txt .
2481 The following commands are available:
2483 .Bl -tag -width ".Ic _ccount"
2490 ) command which follows.
2494 The comment-command causes the entire line to be ignored.
2496 this really is a normal command which' purpose is to discard its
2499 indicating special character, which means that, e.g., trailing comments
2500 on a line are not possible.
2504 Goes to the next message in sequence and types it
2510 Display the preceding message, or the n'th previous message if given
2511 a numeric argument n.
2515 Show the current message number (the
2520 Show a brief summary of commands.
2521 \*(OP Given an argument a synopsis for the command in question is
2522 shown instead; commands can be abbreviated in general and this command
2523 can be used to see the full expansion of an abbreviation including the
2524 synopsis, try, e.g.,
2529 and see how the output changes.
2539 Interprets the remainder of the word as a macro name and passes it
2544 is a shorter synonym for
2545 .Ql call Ar mymacro .
2549 (ac) Creates, selects or lists (an) account(s).
2550 An account is a group of commands and variable settings which together
2551 usually arrange the environment for the purpose of creating a system login.
2552 Without any argument a listing of all defined accounts and their content
2554 A specific account can be activated by giving solely its name, resulting
2555 in the system mailbox or inbox of that account to be activated as via an
2556 explicit use of the command
2558 The two argument form is identical to defining a macro as via
2561 .Bd -literal -offset indent
2565 set from="myname@myisp.example (My Name)"
2566 set smtp=smtp://mylogin@smtp.myisp.example
2570 creates an account named
2572 which can later be selected by specifying
2576 (case-insensitive) always exists.
2578 are enabled by default and localize account settings \(en different to
2579 normal macros the settings will be reverted once the account is switched off.
2580 Accounts can be deleted via
2585 (a) With no arguments, shows all currently-defined aliases.
2586 With one argument, shows that alias.
2587 With more than one argument,
2588 creates a new alias or appends to an existing one.
2590 can be used to delete aliases.
2594 (alt) Manage a list of alternate addresses / names of the active user,
2595 members of which will be removed from recipient lists when replying to
2598 variable is not set).
2599 If arguments are given the set of alternate names is replaced by them,
2600 without arguments the current set is displayed.
2604 Takes a message list and marks each message as having been answered.
2605 This mark has no technical meaning in the mail system;
2606 it just causes messages to be marked in the header summary,
2607 and makes them specially addressable.
2611 Calls a macro that has been created via
2616 (ch) Change the working directory to
2618 or the given argument.
2624 \*(OP Only applicable to S/MIME signed messages.
2625 Takes a message list and a file name and saves the certificates
2626 contained within the message signatures to the named file in both
2627 human-readable and PEM format.
2628 The certificates can later be used to send encrypted messages to the
2629 respective message senders by setting
2630 .Va smime-encrypt-USER@HOST
2635 (ch) Change the working directory to
2637 or the given argument.
2643 Only applicable to threaded mode.
2644 Takes a message list and makes all replies to these messages invisible
2645 in header summaries, unless they are in state
2651 \*(OP Manage colour mappings for the type of colour given as the
2652 (case-insensitive) first argument, which must be one of
2654 for 256-colour terminals,
2659 for the standard 8-colour ANSI / ISO 6429 color palette and
2663 for monochrome terminals.
2664 Monochrome terminals cannot deal with colours, but only (some) font
2668 Without further arguments the list of all currently defined mappings
2669 for the given colour type is shown (as a special case giving
2673 will iterate over all types in order).
2674 Otherwise the second argument defines the mappable slot, the third
2675 argument a (comma-separated list of) colour and font attribute
2676 specification(s), and the optional fourth argument can be used to
2677 specify a precondition: if conditioned mappings exist they are tested in
2678 (creation) order unless a (case-insensitive) match has been found, and
2679 the default mapping (if any has been established) will only be chosen as
2681 The types of precondition available depend on the mappable slot, the
2682 following of which exist:
2685 Mappings prefixed with
2687 are used for the \*(OPal builtin Mailx-Line-Editor (MLE, see
2688 .Sx "On terminal control and line editor" )
2689 and don't support preconditions.
2691 .Bl -tag -compact -width view-partinfo
2693 This mapping is used for the position indicator that is visible when
2694 a line cannot be fully displayed on the screen.
2701 Mappings prefixed with
2703 are used in header summaries, and they all understand the preconditions
2705 (the current message) and
2707 for elder messages (only honoured in conjunction with
2708 .Va datefield-markout-older ) .
2710 .Bl -tag -compact -width view-partinfo
2712 This mapping is used for the
2714 that can be created with the
2718 formats of the variable
2721 For the complete header summary line except the
2723 and the thread structure.
2725 For the thread structure which can be created with the
2727 format of the variable
2732 Mappings prefixed with
2734 are used when displaying messages.
2736 .Bl -tag -compact -width view-partinfo
2738 This mapping is used for so-called
2740 lines, which are MBOX file format specific header lines.
2743 A comma-separated list of headers to which the mapping applies may be
2744 given as a precondition; if the \*(OPal regular expression support is
2745 available then if any of the
2747 (extended) regular expression characters is seen the precondition will
2748 be evaluated as (an extended) one.
2750 For the introductional message info line.
2751 .It Cd view-partinfo
2752 For MIME part info lines.
2756 The following (case-insensitive) colour definitions and font attributes
2757 are understood, multiple of which can be specified in a comma-separated
2767 It is possible (and often applicable) to specify multiple font
2768 attributes for a single mapping.
2771 foreground colour attribute:
2781 To specify a 256-color mode a decimal number colour specification in
2782 the range 0 to 255, inclusive, is supported, and interpreted as follows:
2784 .Bl -tag -compact -width "999 - 999"
2786 the standard ISO 6429 colors, as above.
2788 high intensity variants of the standard colors.
2790 216 colors in tuples of 6.
2792 grayscale from black to white in 24 steps.
2794 .Bd -literal -offset indent
2796 fg() { printf "\e033[38;5;${1}m($1)"; }
2797 bg() { printf "\e033[48;5;${1}m($1)"; }
2799 while [ $i -lt 256 ]; do fg $i; i=$(($i + 1)); done
2800 printf "\e033[0m\en"
2802 while [ $i -lt 256 ]; do bg $i; i=$(($i + 1)); done
2803 printf "\e033[0m\en"
2807 background colour attribute (see
2809 for possible values).
2813 Mappings may be removed with the command
2815 For a generic overview see the section
2816 .Sx "Coloured display" .
2821 (C) Copy messages to files whose names are derived from the author of
2822 the respective message and don't mark them as being saved;
2823 otherwise identical to
2828 (c) Copy messages to the named file and don't mark them as being saved;
2829 otherwise identical to
2834 With no arguments, shows all currently-defined custom headers.
2835 With one argument, shows that custom header.
2836 With more than one argument, creates a new or replaces an existing
2837 custom header with the name given as the first argument, the content of
2838 which being defined by the concatenated remaining arguments.
2840 can be used to delete custom headers.
2841 \*(ID Overwriting of automatically managed headers is neither supported
2843 Defined custom headers will be injected into newly composed or forwarded
2846 .Dl customhdr OpenPGP id=12345678; url=http://www.YYY.ZZ
2850 may also be used to inject custom headers; it is covered by
2855 Show the name of the current working directory.
2859 \*(OP For unencrypted messages this command is identical to
2861 Encrypted messages are first decrypted, if possible, and then copied.
2865 \*(OP For unencrypted messages this command is identical to
2867 Encrypted messages are first decrypted, if possible, and then copied.
2871 Without arguments the current list of macros, including their content,
2872 is shown, otherwise a macro is defined.
2873 A macro definition is a sequence of commands in the following form:
2874 .Bd -literal -offset indent
2883 A defined macro can be invoked explicitly by using the
2887 commands, or implicitly if a macro hook is triggered, e.g., a
2889 Note that interpretation of
2891 depends on how (i.e.,
2893 normal macro, folder hook, hook, account switch) the macro is invoked.
2894 Macros can be deleted via
2898 Macro behaviour, including option localization, will change in v15.
2899 Please be aware of that and possibly embed a version check in a resource
2904 (d) Marks the given message list as
2906 Deleted messages will neither be saved in
2908 nor will they be available for most other commands.
2920 Deletes the current message and displays the next message.
2921 If there is no next message, \*(UA says
2928 up or down by one message when given
2932 argument, respectively.
2936 Takes a message list and marks each given message as a draft.
2937 This mark has no technical meaning in the mail system;
2938 it just causes messages to be marked in the header summary,
2939 and makes them specially addressable.
2943 (ec) Echoes its arguments,
2944 resolving special names as documented for the command
2946 The escape sequences
2958 are interpreted just as they are by
2960 (proper quoting provided).
2964 (e) Point the text editor (as defined in
2966 at each message from the given list in turn.
2967 Modified contents are discarded unless the
2974 .Ic if Ns / Ns Ic elif Ns / Ns Ic else Ns / Ns Ic endif
2975 conditional \(em if the condition of a preceeding
2977 was false, check the following condition and execute the following block
2978 if it evaluates true.
2983 .Ic if Ns / Ns Ic elif Ns / Ns Ic else Ns / Ns Ic endif
2984 conditional \(em if none of the conditions of the preceeding
2988 commands was true, the
2994 (en) Marks the end of an
2995 .Ic if Ns / Ns Ic elif Ns / Ns Ic else Ns / Ns Ic endif
2996 conditional execution block.
3000 \*(OP Since \*(UA uses the console as a user interface it can happen
3001 that messages scroll by too fast to become recognized.
3002 Optionally an error message ring queue is available which stores
3003 duplicates of any error message and notifies the user in interactive
3004 sessions whenever a new error has occurred.
3005 The queue is finite: if its maximum size is reached any new message
3006 replaces the eldest.
3009 can be used to manage this message queue: if given
3011 or no argument the queue will be displayed and cleared,
3013 will only clear all messages from the queue.
3017 (ex or x) Exit from \*(UA without changing the active mailbox and skip
3018 any saving of messages in
3020 as well as a possibly tracked line editor history file.
3024 Show the list of features that have been compiled into \*(UA.
3025 (Outputs the contents of the variable
3032 but open the mailbox readonly.
3036 (fi) The file command switches to a new mailbox.
3037 Without arguments it shows status information of the current mailbox.
3038 If an argument is given, it will write out changes (such as deletions)
3039 the user has made and open a new mailbox.
3040 Some special conventions are recognized for the
3044 .Bl -tag -compact -offset indent -width ".Ar %:__lespec"
3046 (number sign) means the previous file,
3048 (percent sign) means the invoking user's system mailbox,
3050 means the system mailbox of
3052 (and never the value of
3054 regardless of its actual setting),
3056 (ampersand) means the invoking user's
3066 expands to the same value as
3068 but the file is handled as a system mailbox by, e.g., the
3072 commands, meaning that messages that have been read in the current
3073 session will be moved to the
3075 mailbox instead of simply being flagged as read.
3078 If the name matches one of the strings defined with the command
3080 it is replaced by its long form and expanded.
3081 If the name ends with
3086 it is treated as being compressed with
3091 respectively, and transparently handled through an intermediate
3092 (un)compression step (using a temporary file) with the according
3093 facility, sufficient support provided.
3094 Likewise, if the named file doesn't exist, but a file with one of the
3095 mentioned compression extensions does, then the name is automatically
3096 expanded and the compressed file is used.
3098 Otherwise, if the name ends with an extension for which
3099 .Va file-hook-load-EXTENSION
3101 .Va file-hook-save-EXTENSION
3102 variables are set, then the given hooks will be used to load and save
3104 and \*(UA will work with an intermediate temporary file.
3106 MBOX files (flat file-based mailboxes) are generally locked during file
3107 operations in order to avoid inconsistencies due to concurrent
3109 \*(OPal Mailbox files which \*(UA treats as system or primary mailboxes
3110 will also be protected by so-called dotlock files, the traditional way
3111 of mail spool file locking: for any file
3115 will be created for the duration of the synchronization \(em
3116 as necessary a privilege-separated dotlock child process will be used
3117 to accommodate for necessary privilege adjustments in order to create
3118 the dotlock file in the same directory
3119 and with the same user and group identities as the file of interest.
3122 for fine-tuning the handling of MBOX files.
3126 refers to a directory with the subdirectories
3131 then it is treated as a folder in
3136 .Dl \*(IN protocol://[user[:password]@]host[:port][/path]
3137 .Dl \*(OU protocol://[user@]host[:port][/path]
3139 is taken as an Internet mailbox specification.
3140 The \*(OPally supported protocols are
3144 (POP3 with SSL/TLS encrypted transport).
3147 part is valid only for IMAP; there it defaults to
3149 Also see the section
3150 .Sx "On URL syntax and credential lookup" .
3154 contains special characters, in particular
3158 they must be escaped in URL notation \(en the command
3160 can be used to show the necessary conversion.
3164 Takes a message list and marks the messages as
3166 ged for urgent/special attention.
3167 This mark has no technical meaning in the mail system;
3168 it just causes messages to be highlighted in the header summary,
3169 and makes them specially addressable.
3178 With no arguments, list the names of the folders in the folder directory.
3179 With an existing folder as an argument,
3180 lists the names of folders below the named folder.
3186 but saves the message in a file named after the local part of the first
3187 recipient's address (instead of in
3194 but saves the message in a file named after the local part of the first
3195 recipient's address (instead of in
3202 but responds to all recipients regardless of the
3207 .It Ic followupsender
3210 but responds to the sender only regardless of the
3226 (f) Takes a list of message specifications and displays a summary of
3227 their message headers, as via
3229 An alias of this command is
3232 .Sx "Specifying messages" .
3238 but saves the message in a file named after the local part of the
3239 recipient's address (instead of in
3244 Takes a message and the address of a recipient
3245 and forwards the message to him.
3246 The text of the original message is included in the new one,
3247 with the value of the
3249 variable preceding it.
3254 commands specify which header fields are included in the new message.
3255 Only the first part of a multipart message is included unless the
3256 .Va forward-as-attachment
3260 is set recipient addresses will be stripped from comments, names etc.
3264 Specifies which header fields are to be ignored with the command
3266 This command has no effect when the
3267 .Va forward-as-attachment
3272 Specifies which header fields are to be retained with the command
3277 This command has no effect when the
3278 .Va forward-as-attachment
3283 Define or list command aliases, so-called ghosts.
3284 Without arguments a list of all currently known aliases is shown.
3285 With one argument the expansion of the given alias is shown.
3286 With two or more arguments a command alias is defined or updated: the
3287 first argument is the name under which the remaining command line should
3288 be accessible, the content of which can be just about anything.
3289 A ghost can be used everywhere a normal command can be used, but always
3290 takes precedence; any arguments that are given to the command alias are
3291 joined onto the alias content, and the resulting string forms the
3292 command line that is, in effect, executed.
3295 .Bd -literal -offset indent
3297 `ghost': no such alias: "xx"
3300 ghost xx "echo hello,"
3309 (h) Show the current group of headers, the size of which depends on
3312 and the style of which can be adjusted with the variable
3314 If a message-specification is given the group of headers containing the
3315 first message therein is shown and the message at the top of the screen
3330 the list of history entries;
3333 argument selects and shows the respective history entry \(en
3336 to accept it, and the history entry will become the new history top.
3337 The default mode if no arguments are given is
3344 Takes a message list and marks each message therein to be saved in the
3345 user's system mailbox instead of in
3347 Does not override the
3350 \*(UA deviates from the POSIX standard with this command, because a
3352 command issued after
3354 will display the following message, not the current one.
3359 (i) Part of the nestable
3360 .Ic if Ns / Ns Ic elif Ns / Ns Ic else Ns / Ns Ic endif
3361 conditional execution construct \(em if the given condition is true then
3362 the encapsulated block is executed.
3363 POSIX only supports the (case-insensitive) conditions
3368 end, all remaining conditions are non-portable extensions; note that
3369 falsely specified conditions cause the execution of the entire
3370 conditional construct until the (matching) closing
3372 command to be suppressed.
3373 The syntax of the nestable
3375 conditional execution construct requires that each condition and syntax
3376 element is surrounded by whitespace.
3378 .Bd -literal -offset indent
3387 The (case-insensitive) condition
3389 erminal will evaluate to true if the standard input is a terminal, i.e.,
3390 in interactive sessions.
3391 Another condition can be any boolean value (see the section
3392 .Sx "INTERNAL VARIABLES"
3393 for textual boolean representations) to mark an enwrapped block as
3396 .Dq always execute .
3397 It is possible to check
3398 .Sx "INTERNAL VARIABLES"
3401 variables for existence or compare their expansion against a user given
3402 value or another variable by using the
3404 .Pf ( Dq variable next )
3405 conditional trigger character;
3406 a variable on the right hand side may be signalled using the same
3408 The variable names may be enclosed in a pair of matching braces.
3411 The available comparison operators are
3415 (less than or equal to),
3421 (greater than or equal to),
3425 (is substring of) and
3427 (is not substring of).
3428 The values of the left and right hand side are treated as strings and
3429 are compared 8-bit byte-wise, ignoring case according to the rules of
3430 the US-ASCII encoding (therefore, dependend on the active locale,
3431 possibly producing false results for strings in the locale encoding).
3432 Except for the substring checks the comparison will instead be performed
3433 arithmetically if both, the user given value as well as the variable
3434 content, can be parsed as numbers (integers).
3435 An unset variable is treated as the empty string.
3438 When the \*(OPal regular expression support is available, the additional
3444 They treat the right hand side as an extended regular expression that is
3445 matched case-insensitively and according to the active
3447 locale, meaning that strings in the locale encoding should be matched
3451 Conditions can be joined via AND-OR lists (where the AND operator is
3453 and the OR operator is
3455 which have equal precedence and will be evaluated with left
3456 associativity, thus using the same syntax that is known for the
3458 It is also possible to form groups of conditions and lists by enclosing
3459 them in pairs of brackets
3460 .Ql [\ \&.\&.\&.\ ] ,
3461 which may be interlocked within each other, and also be joined via
3465 The results of individual conditions and entire groups may be modified
3466 via unary operators: the unary operator
3468 will reverse the result.
3470 .Bd -literal -offset indent
3474 if $ttycharset == "UTF-8"
3475 echo *ttycharset* is set to UTF-8, case-insensitively
3479 echo These two variables are equal
3481 if $version-major >= 15
3482 echo Running a new version..
3483 if $features =@ "regex"
3484 if $TERM =~ "^xterm\&.*"
3485 echo ..in an X terminal
3488 if [ [ true ] && [ [ ${debug} ] || [ $verbose ] ] ]
3491 if true && $debug || ${verbose}
3492 echo Left associativity, as is known from the shell
3494 if ! ! true && ! [ ! $debug && ! $verbose ]
3495 echo Unary operator support
3503 Without arguments the list of ignored header fields is shown,
3504 otherwise the given list of header fields is added to the ignore list:
3505 Header fields in the ignore list are not shown on the terminal when
3506 a message is displayed.
3507 To display a message in its entirety, use the commands
3518 Shows the names of all available commands, alphabetically sorted.
3522 This command can be used to localize changes to variables, meaning that
3523 their state will be reverted to the former one once the covered scope
3525 It can only be used inside of macro definition blocks introduced by
3529 and is interpreted as a boolean (string, see
3530 .Sx "INTERNAL VARIABLES" ) ;
3533 of an account is left once it is switched off again.
3534 .Bd -literal -offset indent
3535 define temporary_settings {
3550 enables change localization and calls
3552 which explicitly resets localization, then any value changes within
3554 will still be reverted by
3559 Reply to messages that come in via known
3562 .Pf ( Ic mlsubscribe )
3563 mailing lists, or pretend to do so (see
3564 .Sx "Mailing lists" ) :
3567 functionality this will actively resort and even remove message
3568 recipients in order to generate a message that is supposed to be sent to
3570 For example it will also implicitly generate a
3571 .Ql Mail-Followup-To:
3572 header if that seems useful, regardless of the setting of the variable
3579 but saves the message in a file named after the local part of the first
3580 recipient's address (instead of in
3585 (m) Takes a (list of) recipient address(es) as (an) argument(s),
3586 or asks on standard input if none were given;
3587 then collects the remaining mail content and sends it out.
3591 (mb) The given message list is to be sent to
3593 when \*(UA is quit; this is the default action unless the
3596 \*(ID This command can only be used in a system mailbox (see
3601 Without any arguments the content of the MIME type cache will displayed.
3602 Otherwise each argument defines a complete MIME type specification of
3603 a type that shall be added (prepended) to the cache.
3604 In any event MIME type sources are loaded first as necessary \(en
3605 .Va mimetypes-load-control
3606 can be used to fine-tune which sources are actually loaded.
3607 Refer to the section on
3608 .Sx "The mime.types files"
3609 for more on MIME type specifications and this topic in general.
3610 MIME type unregistration and cache resets can be triggered with
3615 Without arguments the list of all currently defined mailing lists
3616 (and their attributes, if any) is shown; a more verbose listing will be
3617 produced if either of
3622 Otherwise all given arguments (which need not be quoted except for
3623 whitespace) will be added and henceforth be recognized as mailing lists.
3624 Mailing lists may be removed via the command
3627 If the \*(OPal regular expression support is available then mailing
3628 lists may also be specified as (extended) regular expressions (see
3634 Without arguments the list of all currently defined mailing lists which
3635 have a subscription attribute is shown; a more verbose listing will be
3636 produced if either of
3641 Otherwise this attribute will be set for all given mailing lists,
3642 newly creating them as necessary (as via
3644 Subscription attributes may be removed via the command
3653 but moves the messages to a file named after the local part of the
3654 sender address of the first message (instead of in
3661 but marks the messages for deletion if they were transferred
3668 but also displays ignored header fields and all MIME parts.
3676 on the given messages, even in non-interactive mode and as long as the
3677 standard output is a terminal.
3683 \*(OP When used without arguments or if
3685 has been given the content of the
3687 cache is shown, loading it first as necessary,
3690 then the cache will only be initialized and
3692 will remove its contents.
3693 Note that \*(UA will try to load the file only once, use
3694 .Ql Ic \&\&netrc Ns \:\0\:clear
3695 to unlock further attempts.
3699 .Sx "On URL syntax and credential lookup" ;
3701 .Sx "The .netrc file"
3702 documents the file format in detail.
3706 Checks for new mail in the current folder without committing any changes
3708 If new mail is present, a message is shown.
3712 the headers of each new message are also shown.
3720 Goes to the next message in sequence and types it.
3721 With an argument list, types the next matching message.
3735 If the current folder is accessed via a network connection, a
3737 command is sent, otherwise no operation is performed.
3743 but also displays ignored header fields and all MIME parts.
3751 on the given messages, even in non-interactive mode and as long as the
3752 standard output is a terminal.
3760 but also pipes ignored header fields and all parts of MIME
3761 .Ql multipart/alternative
3766 (pi) Takes a message list and a shell command
3767 and pipes the messages through the command.
3768 Without an argument the current message is piped through the command
3775 every message is followed by a formfeed character.
3796 (q) Terminates the session, saving all undeleted, unsaved messages in
3799 preserving all messages marked with
3803 or never referenced in the system mailbox,
3804 and removing all other messages from the system mailbox.
3805 If new mail has arrived during the session,
3807 .Dq You have new mail
3809 If given while editing a mailbox file with the command line flag
3811 then the edit file is rewritten.
3812 A return to the shell is effected,
3813 unless the rewrite of edit file fails,
3814 in which case the user can escape with the exit command.
3828 Removes the named folders.
3829 The user is asked for confirmation in interactive mode.
3833 Takes the name of an existing folder
3834 and the name for the new folder
3835 and renames the first to the second one.
3836 Both folders must be of the same type.
3840 (R) Reply to originator.
3841 Does not reply to other recipients of the original message.
3843 will exchange this command with
3847 is set the recipient address will be stripped from comments, names etc.
3851 (r) Take a message and group-responds to it by addressing the sender
3854 .Va followup-to-honour ,
3857 .Va recipients-in-cc
3858 influence response behaviour.
3861 offers special support for replying to mailing lists.
3864 is set recipient addresses will be stripped from comments, names etc.
3877 but initiates a group-reply regardless of the value of
3884 but responds to the sender only regardless of the value of
3891 but does not add any header lines.
3892 This is not a way to hide the sender's identity,
3893 but useful for sending a message again to the same recipients.
3897 Takes a list of messages and a user name
3898 and sends each message to the named user.
3900 and related header fields are prepended to the new copy of the message.
3918 .It Ic respondsender
3924 (ret) Without arguments the list of retained header fields is shown,
3925 otherwise the given list of header fields is added to the retain list:
3926 Header fields in the retain list are shown on the terminal when
3927 a message is displayed, all other header fields are suppressed.
3928 To display a message in its entirety, use the commands
3937 takes precedence over the mentioned.
3943 but saves the messages in a file named after the local part of the
3944 sender of the first message instead of (in
3946 and) taking a filename argument.
3950 (s) Takes a message list and a filename and appends each message in turn
3951 to the end of the file.
3952 If no filename is given, the
3955 The filename in quotes, followed by the generated character count
3956 is echoed on the user's terminal.
3957 If editing a system mailbox the messages are marked for deletion.
3958 Filename interpretation as described for the
3960 command is performed.
3977 Header fields thus marked are filtered out when saving a message by
3979 or when automatically saving to
3981 This command should only be applied to header fields that do not contain
3982 information needed to decode the message,
3983 as MIME content fields do.
3995 Header fields thus marked are the only ones saved with a message when
3998 or when automatically saving to
4003 The use of this command is strongly discouraged since it may strip
4004 header fields that are needed to decode the message correctly.
4008 Takes a message specification (list) and displays a header summary of
4009 all matching messages, as via
4011 This command is an alias of
4014 .Sx "Specifying messages" .
4018 Takes a message list and marks all messages as having been read.
4022 (se) Without arguments this command shows all variables and their
4023 values which are currently known to \*(UA.
4024 Setting any of the variables
4028 changes the output format to BSD style, otherwise a properly quoted
4029 listing is produced.
4034 has been set twice then the listing is modified to mark out assembled
4037 Otherwise modifies (set and unsets) the given variables.
4038 Arguments are of the form
4040 (no space before or after
4044 if there is no value.
4045 Quotation marks may be placed around any part of the assignment
4046 statement to quote blanks or tabs, e.g.,
4048 .Dl set indentprefix="->"
4050 If an argument begins with
4054 the effect is the same as invoking the
4056 command with the remaining part of the variable
4057 .Pf ( Ql unset save ) .
4063 except that the variables are also exported into the program environment;
4064 since this task requires native host support the command will always
4065 report error if that is not available (but still act like
4068 This operation is a no-op unless all resource files have been loaded.
4074 (sh) Invokes an interactive version of the shell.
4078 Without arguments the list of all currently defined shortcuts is
4080 Otherwise all given arguments (which need not be quoted except for
4081 whitespace) are treated as pairs of shortcuts and their expansions,
4082 creating new or changing already existing shortcuts, as necessary.
4083 Shortcuts may be removed via the command
4085 The expansion strings should be in the syntax that has been described
4094 but performs neither MIME decoding nor decryption, so that the raw
4095 message text is shown.
4099 (si) Shows the size in characters of each message of the given
4104 Shows the current sorting criterion when used without an argument.
4105 Otherwise creates a sorted representation of the current folder,
4108 command and the addressing modes such that they refer to messages in
4110 Message numbers are the same as in regular mode.
4114 a header summary in the new order is also displayed.
4115 Automatic folder sorting can be enabled by setting the
4117 variable, as in, e.g.,
4118 .Ql set autosort=thread .
4119 Possible sorting criterions are:
4121 .Bl -tag -compact -offset indent -width "subject"
4123 Sort the messages by their
4125 field, that is by the time they were sent.
4127 Sort messages by the value of their
4129 field, that is by the address of the sender.
4132 variable is set, the sender's real name (if any) is used.
4134 Sort the messages by their size.
4136 \*(OP Sort the message by their spam score, as has been classified by
4139 Sort the messages by their message status.
4141 Sort the messages by their subject.
4143 Create a threaded display.
4145 Sort messages by the value of their
4147 field, that is by the address of the recipient.
4150 variable is set, the recipient's real name (if any) is used.
4155 (so) The source command reads commands from the given file, which is
4156 subject to the usual filename expansions (see introductional words of
4158 If the given argument ends with a vertical bar
4160 then the argument will instead be interpreted as a shell command and
4161 \*(UA will read the output generated by it.
4164 cannot be used from within macros that execute as
4165 .Va folder-hook Ns s
4168 i.e., it can only be called from macros that were
4175 (beside not supporting pipe syntax a.k.a. shell command input) is that
4176 this command will not generate an error if the given file argument
4177 cannot be opened successfully.
4178 This can matter in, e.g., resource files, since loading of those is
4179 stopped when an error is encountered.
4183 \*(OP Takes a list of messages and clears their
4189 \*(OP Takes a list of messages and causes the
4191 to forget it has ever used them to train its Bayesian filter.
4192 Unless otherwise noted the
4194 flag of the message is inspected to chose wether a message shall be
4202 \*(OP Takes a list of messages and informs the Bayesian filter of the
4206 This also clears the
4208 flag of the messages in question.
4212 \*(OP Takes a list of messages and rates them using the configured
4213 .Va spam-interface ,
4214 without modifying the messages, but setting their
4216 flag as appropriate; because the spam rating headers are lost the rate
4217 will be forgotten once the mailbox is left.
4218 Refer to the manual section
4220 for the complete picture of spam handling in \*(UA.
4224 \*(OP Takes a list of messages and sets their
4230 \*(OP Takes a list of messages and informs the Bayesian filter of the
4236 flag of the messages in question.
4245 Create a threaded representation of the current folder,
4246 i.\|e. indent messages that are replies to other messages in the header
4247 display and change the
4249 command and the addressing modes such that they refer to messages in the
4251 Message numbers are the same as in unthreaded mode.
4255 a header summary in threaded order is also displayed.
4259 (to) Takes a message list and displays the top few lines of each.
4260 The number of lines shown is controlled by the variable
4262 and defaults to five.
4266 (tou) Takes a message list and marks the messages for saving in
4268 \*(UA deviates from the POSIX standard with this command,
4271 command will display the following message instead of the current one.
4277 but also displays out ignored header fields and all parts of MIME
4278 .Ql multipart/alternative
4283 (t) Takes a message list and types out each message on the user's
4289 For MIME multipart messages, all parts with a content type of
4293 are shown, the other are hidden except for their headers.
4294 Messages are decrypted and converted to the terminal character set
4299 Delete all given accounts.
4300 An error message is shown if a given account is not defined.
4303 will discard all existing accounts.
4307 (una) Takes a list of names defined by alias commands
4308 and discards the remembered groups of users.
4311 will discard all existing aliases.
4315 Takes a message list and marks each message as not having been answered.
4319 Only applicable to threaded mode.
4320 Takes a message list and makes the message and all replies to it visible
4321 in header summaries again.
4322 When a message becomes the current message,
4323 it is automatically made visible.
4324 Also when a message with collapsed replies is displayed,
4325 all of these are automatically uncollapsed.
4331 mapping for the given colour type (see
4333 for a list of types) and mapping; if the optional precondition argument
4334 is used then only the exact tuple of mapping and precondition is removed.
4337 will remove all mappings (no precondition allowed).
4339 .Sx "Coloured display"
4340 for the general picture.
4344 Deletes the custom headers given as arguments.
4347 will remove all custom headers.
4351 Undefine all given macros.
4352 An error message is shown if a given macro is not defined.
4355 will discard all existing macros.
4359 (u) Takes a message list and marks each message as not being deleted.
4363 Takes a message list and
4369 Takes a message list and marks each message as not being
4374 Removes the header field names from the list of ignored fields for the
4379 will remove all fields.
4383 Removes the header field names from the list of retained fields for the
4388 will remove all fields.
4392 Remove all the given command
4396 will remove all ghosts.
4400 Removes the header field names from the list of ignored fields.
4403 will remove all fields.
4407 Delete all given MIME types, e.g.,
4408 .Ql unmimetype text/plain
4409 will remove all registered specifications for the MIME type
4413 will discard all existing MIME types, just as will
4415 but which also reenables cache initialization via
4416 .Va mimetypes-load-control .
4420 Forget about all the given mailing lists.
4423 will remove all lists.
4428 .It Ic unmlsubscribe
4429 Remove the subscription attribute from all given mailing lists.
4432 will clear the attribute from all lists which have it set.
4443 Takes a message list and marks each message as not having been read.
4447 Removes the header field names from the list of retained fields.
4450 will remove all fields.
4454 Removes the header field names from the list of ignored fields for
4458 will remove all fields.
4462 Removes the header field names from the list of retained fields for
4466 will remove all fields.
4470 (uns) Takes a list of option names and discards their remembered values;
4478 except that the variables are also removed from the program environment;
4479 since this task requires native host support the command will always
4480 report error if that is not available (but still act like
4483 This operation is a no-op unless all resource files have been loaded.
4489 Deletes the shortcut names given as arguments.
4492 will remove all shortcuts.
4496 Disable sorted or threaded mode
4502 return to normal message order and,
4506 displays a header summary.
4516 Decode the given URL-encoded string arguments and show the results.
4517 Note the resulting strings may not be valid in the current locale, see
4522 URL-encode the given arguments and show the results.
4523 Because the arguments effectively are in the character set of the
4524 current locale the results will vary accordingly unless the input solely
4525 consists of characters in the portable character set, see
4526 .Sx "Character sets" .
4530 Edit the values of or create the given variable(s) in the
4532 Boolean variables cannot be edited.
4536 Show informations about all the given variables.
4537 \*(UA knows about a finite set of known builtin variables that are
4538 subdivided further in boolean and value variants;
4539 they may have special properties, like
4541 (setting may not be changed) and
4543 meaning that the value is generated on-the-fly as necessary.
4544 Beside those known variables an infinite number of unknown, so-called
4546 variables, which are expected to be able to store values, may exist.
4547 .Bd -literal -offset indent
4549 ? varshow sendwait version-major foo bar
4550 "sendwait": (73) boolean: set=1 (ENVIRON=0)
4551 "version-major": (192) value, read-only, virtual:\e
4552 set=1 (ENVIRON=0) value<14>
4553 "foo": (assembled) set=1 (ENVIRON=0) value<bar>
4554 "bar": (assembled) set=0 (ENVIRON=0) value<NULL>
4559 \*(OP Takes a message list and verifies each message.
4560 If a message is not a S/MIME signed message,
4561 verification will fail for it.
4562 The verification process checks if the message was signed using a valid
4564 if the message sender's email address matches one of those contained
4565 within the certificate,
4566 and if the message content has been altered.
4570 (v) Takes a message list and invokes the display editor on each message.
4571 Modified contents are discarded unless the
4577 (w) For conventional messages the body without all headers is written.
4578 The output is decrypted and converted to its native format as necessary.
4579 If the output file exists, the text is appended.
4580 If a message is in MIME multipart format its first part is written to
4581 the specified file as for conventional messages,
4582 and the user is asked for a filename to save each other part.
4583 For convience saving of each part may be skipped by giving an empty value;
4584 the same result can also be achieved by writing it to
4586 For the second and subsequent parts a leading
4588 character causes the part to be piped to the remainder of the user input
4589 interpreted as a shell command;
4590 otherwise the user input is expanded as usually for folders,
4591 e.g., tilde expansion is performed.
4592 In non-interactive mode, only the parts of the multipart message
4593 that have a filename given in the part header are written,
4594 the others are discarded.
4595 The original message is never marked for deletion in the originating
4598 the contents of the destination file are overwritten if the file
4600 No special handling of compressed files is performed.
4609 \*(UA presents message headers in windowfuls as described under the
4612 This command scrolls to the next window of messages.
4613 If an argument is given,
4614 it specifies the window to use.
4615 A number prefixed by
4619 indicates that the window is calculated in relation to the current position.
4620 A number without a prefix specifies an absolute window number,
4623 lets \*(UA scroll to the last window of messages.
4629 but scrolls to the next or previous window that contains at least one
4638 .\" .Sh TILDE ESCAPES {{{
4641 Here is a summary of the tilde escapes,
4642 which are used to perform special functions when composing messages.
4643 Tilde escapes are only recognized at the beginning of lines.
4646 is somewhat of a misnomer since the actual escape character can be
4647 changed by adjusting the option
4650 .Bl -tag -width ".Ic __ filename"
4653 Insert the string of text in the message prefaced by a single
4655 (If the escape character has been changed,
4656 that character must be doubled
4657 in order to send it at the beginning of a line.)
4660 .It Ic ~! Ar command
4661 Execute the indicated shell
4663 then return to the message.
4667 Same effect as typing the end-of-file character.
4670 .It Ic ~: Ar \*(UA-command Ns \0or Ic ~_ Ar \*(UA-command
4671 Execute the given \*(UA command.
4672 Not all commands, however, are allowed.
4676 Write a summary of command escapes.
4679 .It Ic ~< Ar filename
4684 .It Ic ~<! Ar command
4686 is executed using the shell.
4687 Its standard output is inserted into the message.
4690 .It Ic ~@ Op Ar filename...
4691 With no arguments, edit the attachment list interactively.
4692 If an attachment's file name is left empty,
4693 that attachment is deleted from the list.
4694 When the end of the attachment list is reached,
4695 \*(UA will ask for further attachments until an empty name is given.
4696 If a given file name solely consists of the number sign
4698 followed by a valid message number of the currently active mailbox, then
4699 the given message is attached as a MIME
4701 and the rest of this section does not apply.
4703 If character set conversion has been compiled into \*(UA, then this mode
4704 gives the user the option to specify input and output character sets,
4705 unless the file extension indicates binary content, in which case \*(UA
4706 asks wether this step shall be skipped for the attachment in question.
4707 If not skipped, then the charset that succeeds to represent the
4708 attachment data will be used in the
4710 MIME parameter of the mail message:
4712 .Bl -bullet -compact
4714 If input and output character sets are specified, then the conversion is
4715 performed on the fly.
4716 The user will be asked repeatedly until the desired conversion succeeds.
4718 If only an output character set is specified, then the input is assumed
4721 charset and will be converted to the given output charset on the fly.
4722 The user will be asked repeatedly until the desired conversion succeeds.
4724 If no character sets are specified at all then the algorithm that is
4725 documented in the section
4726 .Sx "Character sets"
4727 is applied, but directly and on the fly.
4728 The user will be asked repeatedly until the desired conversion succeeds.
4730 Finally, if an input-, but no output character set is specified, then no
4731 conversion is ever performed, but the
4733 MIME parameter value will still be set to the user input.
4735 The character set selection loop can be left by typing
4737 i.e., causing an interrupt.
4738 .\" \*(OU next sentence
4739 Note that before \*(UA version 15.0 this terminates the entire
4740 current attachment selection, not only the character set selection.
4743 Without character set conversion support, \*(UA will ask for the input
4744 character set only, and it'll set the
4746 MIME parameter value to the given input, if any;
4747 if no user input is seen then the
4749 character set will be used for the parameter value instead.
4750 Note that the file extension check isn't performed in this mode, since
4751 no conversion will take place anyway.
4753 Note that in non-interactive mode, for reproduceabilities sake, there
4754 will always be two questions for each attachment, regardless of wether
4755 character set conversion is available and what the file extension is.
4756 The first asks for the filename, and the second asks for the input
4757 character set to be passed through to the corresponding MIME parameter;
4758 no conversion will be tried if there is input to the latter question,
4759 otherwise the usual conversion algorithm, as above, is applied.
4760 For message attachments, the answer to the second question is completely
4765 arguments are specified for the
4767 command they are treated as a comma-separated list of files,
4768 which are all expanded and appended to the end of the attachment list.
4769 (Commas need to be escaped with backslash, but filenames with leading or
4770 trailing whitespace can only be added via the command line or the first
4772 Message attachments can only be added via the first method;
4773 filenames which clash with message numbers can only be added via the
4774 command line or the second method.)
4775 In this mode the (text) attachments are assumed to be in
4777 encoding, and will be evaluated as documented in the section
4778 .Sx "Character sets" .
4782 Inserts the string contained in the
4785 .Ql Ic ~i Ns \0Sign ) .
4786 The escape sequences tabulator
4794 Inserts the string contained in the
4797 .Ql Ic ~i Ns \0sign ) .
4798 The escape sequences tabulator
4805 .It Ic ~b Ar name ...
4806 Add the given names to the list of blind carbon copy recipients.
4809 .It Ic ~c Ar name ...
4810 Add the given names to the list of carbon copy recipients.
4814 Read the file specified by the
4816 variable into the message.
4820 Invoke the text editor on the message collected so far.
4821 After the editing session is finished,
4822 the user may continue appending text to the message.
4825 .It Ic ~F Ar messages
4826 Read the named messages into the message being sent, including all
4827 message headers and MIME parts.
4828 If no messages are specified, read in the current message.
4831 .It Ic ~f Ar messages
4832 Read the named messages into the message being sent.
4833 If no messages are specified, read in the current message.
4837 lists are used to modify the message headers.
4838 For MIME multipart messages,
4839 only the first displayable part is included.
4843 Edit the message header fields
4848 by typing each one in turn and allowing the user to edit the field.
4849 The default values for these fields originate from the
4857 Edit the message header fields
4863 by typing each one in turn and allowing the user to edit the field.
4866 .It Ic ~i Ar variable
4867 Insert the value of the specified variable into the message,
4868 adding a newline character at the end.
4869 The message remains unaltered if the variable is unset or empty.
4870 The escape sequences tabulator
4877 .It Ic ~M Ar messages
4878 Read the named messages into the message being sent,
4881 If no messages are specified, read the current message.
4884 .It Ic ~m Ar messages
4885 Read the named messages into the message being sent,
4888 If no messages are specified, read the current message.
4892 lists are used to modify the message headers.
4893 For MIME multipart messages,
4894 only the first displayable part is included.
4898 Display the message collected so far,
4899 prefaced by the message header fields
4900 and followed by the attachment list, if any.
4904 Abort the message being sent,
4905 copying it to the file specified by the
4912 .It Ic ~R Ar filename
4913 Read the named file into the message, indented by
4917 .It Ic ~r Ar filename
4918 Read the named file into the message.
4922 Cause the named string to become the current subject field.
4925 .It Ic ~t Ar name ...
4926 Add the given name(s) to the direct recipient list.
4929 .It Ic ~U Ar messages
4930 Read in the given / current message(s) excluding all headers, indented by
4934 .It Ic ~u Ar messages
4935 Read in the given / current message(s), excluding all headers.
4939 Invoke an alternate editor (defined by the
4941 option) on the message collected so far.
4942 Usually, the alternate editor will be a screen editor.
4943 After the editor is quit,
4944 the user may resume appending text to the end of the message.
4947 .It Ic ~w Ar filename
4948 Write the message onto the named file.
4950 the message is appended to it.
4956 except that the message is not saved at all.
4959 .It Ic ~| Ar command
4960 Pipe the message through the specified filter command.
4961 If the command gives no output or terminates abnormally,
4962 retain the original text of the message.
4965 is often used as a rejustifying filter.
4970 .\" .Sh INTERNAL VARIABLES {{{
4971 .Sh "INTERNAL VARIABLES"
4973 Internal \*(UA variables are controlled via the
4977 commands; prefixing a variable name with the string
4981 has the same effect as using
4987 Creation or editing of variables can be performed in the
4992 will give more insight on the given variable(s), and
4994 when called without arguments, will show a listing of all variables.
4995 Variables are also implicitly inherited from the program
4997 and can be set explicitly via the command line option
5001 Two different kind of variables exist.
5002 There are boolean variables, which can only be in one of the two states
5006 and value variables with a(n optional) string value.
5007 For the latter proper quoting is necessary upon assignment time:
5008 To embed whitespace (space and tabulator) in a value it either needs to
5009 be escaped with a backslash character, or the entire value must be
5010 enclosed in (double or single) quotation marks;
5011 To use quotation marks identical to those used to enclose the value,
5012 escape them with a backslash character.
5013 The backslash character has no special meaning except in these cases.
5015 .Bd -literal -offset indent
5016 set one=val\e 1 two="val 2" \e
5017 three='val "3"' four='val \e'4\e''
5018 varshow one two three four
5019 unset one two three four
5023 Dependent upon the actual option the string values will be interpreted
5024 as numbers, colour names, normal text etc., but there also exists
5025 a special kind of string value, the
5026 .Dq boolean string ,
5027 which must either be a decimal integer (in which case
5031 and any other value is true) or any of the (case-insensitive) strings
5036 for a false boolean and
5041 for a true boolean; a special kind of boolean string is the
5043 which is a boolean string that can optionally be prefixed with the
5044 (case-insensitive) term
5048 which causes prompting of the user in interactive mode, with the given
5049 boolean as the default value.
5051 .\" .Ss "Initial settings" {{{
5052 .\" (Keep in SYNC: ./nail.h:okeys, ./nail.rc, ./nail.1:"Initial settings")
5053 .Ss "Initial Settings"
5055 The standard POSIX 2008/Cor 1-2013 mandates the following initial
5061 .Pf no Va autoprint ,
5075 .Pf no Va ignoreeof ,
5077 .Pf no Va keepsave ,
5079 .Pf no Va outfolder ,
5084 (note that \*(UA deviates from the standard by using
5088 special prompt escape results in
5096 .Pf no Va sendwait ,
5105 Notes: \*(UA doesn't support the
5107 variable \(en use command line options or
5108 .Va sendmail-arguments
5109 to pass options through to a MTA.
5110 And the default global
5112 file (which is loaded unless the
5114 command line flag has been used or the
5115 .Ev NAIL_NO_SYSTEM_RC
5116 environment variable is set) bends those initial settings a bit, e.g.,
5117 it sets the variables
5122 to name a few, calls
5124 etc., and should thus be taken into account.
5127 .\" .Ss "Variables" {{{
5130 .Bl -tag -width ".It Va _utoprin_"
5132 .It Va add-file-recipients
5133 \*(BO When file or pipe recipients have been specified,
5134 mention them in the corresponding address fields of the message instead
5135 of silently stripping them from their recipient list.
5136 By default such addressees are not mentioned.
5138 .Mx Va agent-shell-lookup
5139 .It Va agent-shell-lookup-USER@HOST , agent-shell-lookup-HOST , \
5141 \*(IN\*(OP Account passwords can be fetched via an external agent
5142 program in order to permit encrypted password storage \(en see
5143 .Sx "On URL syntax and credential lookup"
5144 for more on credential lookup.
5145 If this is set then the content is interpreted as a shell command the
5146 output of which (with newline characters removed) is treated as the
5147 account password shall the command succeed (and have produced non-empty
5148 non-newline output); e.g., via
5150 .Bd -literal -offset indent
5151 $ echo PASSWORD > .pass
5153 $ eval `gpg-agent --daemon \e
5154 --pinentry-program=/usr/bin/pinentry-curses \e
5155 --max-cache-ttl 99999 --default-cache-ttl 99999`
5156 $ echo 'set agent-shell-lookup="gpg -d .pass.gpg"' \e
5160 A couple of environment variables will be set for the agent:
5162 .Bl -tag -compact -width ".It Ev _AIL_TMPDIR[337]"
5164 The temporary directory that \*(UA uses.
5165 Usually identical to
5167 but guaranteed to be set and usable by child processes;
5168 to ensure the latter condition for
5174 for which the password is looked up.
5175 .It Ev NAIL_USER_ENC
5176 The URL percent-encoded variant of
5179 The plain machine hostname of the user account.
5180 .It Ev NAIL_HOST_PORT
5183 (hostname possibly including port) of the user account.
5188 \*(BO Causes only the local part to be evaluated
5189 when comparing addresses.
5193 \*(BO Causes messages saved in
5195 to be appended to the end rather than prepended.
5196 This should always be set.
5200 \*(BO Causes \*(UA to prompt for the subject of each message sent.
5201 If the user responds with simply a newline,
5202 no subject field will be sent.
5206 \*(BO Causes the prompts for
5210 lists to appear after the message has been edited.
5214 \*(BO If set, \*(UA asks for files to attach at the end of each message,
5215 shall the list be found empty at that time.
5216 An empty line finalizes the list.
5220 \*(BO Causes the user to be prompted for carbon copy recipients
5221 (at the end of each message if
5225 are set) shall the list be found empty (at that time).
5226 An empty line finalizes the list.
5230 \*(BO Causes the user to be prompted for blind carbon copy
5231 recipients (at the end of each message if
5235 are set) shall the list be found empty (at that time).
5236 An empty line finalizes the list.
5240 \*(BO\*(OP Causes the user to be prompted if the message is to be
5241 signed at the end of each message.
5244 variable is ignored when this variable is set.
5248 \*(BO Alternative name for
5255 .It Va attachment-ask-content-description , \
5256 attachment-ask-content-disposition , \
5257 attachment-ask-content-id , \
5258 attachment-ask-content-type
5259 \*(BO If set then the user will be prompted for some attachment
5260 information when editing the attachment list.
5261 It is advisable to not use these but for the first of the variables;
5262 even for that it has to be noted that the data is used
5268 A sequence of characters to display in the
5272 as shown in the display of
5274 each for one type of messages (see
5275 .Sx "Message states" ) ,
5276 with the default being
5279 .Ql NU\ \ *HMFAT+\-$~
5282 variable is set, in the following order:
5284 .Bl -tag -compact -offset indent -width ".It Ql _"
5306 start of a collapsed thread.
5308 an uncollapsed thread (TODO ignored for now).
5312 classified as possible spam.
5318 Specifies a list of recipients to which a blind carbon copy of each
5319 outgoing message will be sent automatically.
5323 Specifies a list of recipients to which a carbon copy of each outgoing
5324 message will be sent automatically.
5328 \*(BO Causes threads to be collapsed automatically when threaded mode
5335 \*(BO Causes the delete command to behave like
5337 thus, after deleting a message the next one will be typed automatically.
5341 \*(BO\*(OB Causes threaded mode (see the
5343 command) to be entered automatically when a folder is opened.
5345 .Ql autosort=thread .
5349 Causes sorted mode (see the
5351 command) to be entered automatically with the value of this option as
5352 sorting method when a folder is opened, e.g.,
5353 .Ql set autosort=thread .
5357 \*(BO Enables the substitution of
5359 by the contents of the last command line in shell escapes.
5362 .It Va batch-exit-on-error
5363 \*(BO If the batch mode has been enabled via the
5365 command line option, then this variable will be consulted whenever \*(UA
5366 completes one operation (returns to the command prompt); if it is set
5367 then \*(UA will terminate if the last operation generated an error.
5371 \*(BO Causes automatic display of a header summary after executing a
5377 \*(BO Sets some cosmetical features to traditional BSD style;
5378 has the same affect as setting
5380 and all other variables prefixed with
5382 it also changes the meaning of the \*(UA specific
5385 escape sequence and changes behaviour of
5387 (which doesn't exist in BSD).
5391 \*(BO Changes the letters shown in the first column of a header
5392 summary to traditional BSD style.
5396 \*(BO Changes the display of columns in a header summary to traditional
5401 \*(BO Changes some informational messages to traditional BSD style.
5407 field to appear immediately after the
5409 field in message headers and with the
5411 .Sx "TILDE ESCAPES" .
5415 \*(BO Changes the output format of the
5417 command to traditional BSD style.
5421 The value that should appear in the
5425 MIME header fields when no character set conversion of the message data
5427 This defaults to US-ASCII, and the chosen character set should be
5428 US-ASCII compatible.
5432 \*(OP The default 8-bit character set that is used as an implicit last
5433 member of the variable
5435 This defaults to UTF-8.
5436 If no character set conversion capabilities are available in \*(UA then
5437 the only supported character set is
5439 Refer to the section
5440 .Sx "Character sets"
5441 for the complete picture of character set conversion in \*(UA.
5444 .It Va charset-unknown-8bit
5445 \*(OP RFC 1428 specifies conditions when internet mail gateways shall
5447 the content of a mail message by using a character set with the name
5449 Because of the unclassified nature of this character set \*(UA will not
5450 be capable to convert this character set to any other character set.
5451 If this variable is set any message part which uses the character set
5453 is assumed to really be in the character set given in the value,
5454 otherwise the (final) value of
5456 is used for this purpose.
5458 This variable will also be taken into account if a MIME type (see
5459 .Sx "The mime.types files" )
5460 of a MIME message part that uses the
5462 character set is forcefully treated as text.
5466 The default value for the
5471 .It Va colour-disable
5472 \*(BO\*(OP Forcefully disable usage of colours.
5473 Also see the section
5474 .Sx "Coloured display" .
5478 \*(BO\*(OP Wether colour shall be used for output that is paged through
5480 Note that pagers may need special flags, e.g.,
5488 in order to support colours.
5489 Often doing manual adjustments is unnecessary since \*(UA may perform
5490 adjustments dependend on the value of the environment variable
5492 (see there for more).
5496 In a(n interactive) terminal session, then if this valued option is set
5497 it'll be used as a threshold to determine how many lines the given
5498 output has to span before it will be displayed via the configured
5502 can be forced by setting this to the value
5504 setting it without a value will deduce the current height of the
5505 terminal screen to compute the treshold (see
5513 \*(OB A variable counterpart of the
5515 command (see there for documentation), interpreted as a comma-separated
5516 list of custom headers to be injected, to include commas in the header
5517 bodies escape them with backslash, e.g.:
5519 .Dl set customhdr="Hdr1: Body1-1\e, Body1-2, Hdr2: Body2"
5525 the message date, if any is to be displayed according to the format of
5527 is by default taken from the
5529 line of the message.
5530 If this variable is set the date as given in the
5532 header field is used instead, converted to local time.
5533 To control the display format of the date assign a valid
5538 format should not be used, because \*(UA doesn't take embedded newlines
5539 into account when calculating how many lines fit onto the screen.)
5541 .Va datefield-markout-older .
5544 .It Va datefield-markout-older
5545 This option, when set in addition to
5549 messages (concept is rather comparable to the
5551 option of the POSIX utility
5553 The content interpretation is identical to
5558 \*(BO Enables debug messages and obsoletion warnings, disables the
5559 actual delivery of messages and also implies
5565 .It Va disposition-notification-send
5567 .Ql Disposition-Notification-To:
5568 header (RFC 3798) with the message.
5572 .\" TODO .It Va disposition-notification-send-HOST
5574 .\".Va disposition-notification-send
5575 .\" for SMTP accounts on a specific host.
5576 .\" TODO .It Va disposition-notification-send-USER@HOST
5578 .\".Va disposition-notification-send
5579 .\"for a specific account.
5583 \*(BO When dot is set, a period
5585 on a line by itself during message input in (interactive) compose mode
5586 will be treated as end-of-message (in addition to the normal end-of-file
5595 .It Va dotlock-ignore-error
5596 \*(BO\*(OP Synchronization of mailboxes which \*(UA treats as system
5597 mailboxes (see the command
5599 will be protected with so-called dotlock files\(emthe traditional mail
5600 spool file locking method\(emin addition to system file locking.
5601 Because \*(UA ships with a privilege-separated dotlock creation program
5602 that should always be able to create such a dotlock file there is no
5603 good reason to ignore dotlock file creation errors, and thus these are
5604 fatal unless this variable is set.
5608 \*(BO If this variable is set then the editor is started automatically
5609 when a message is composed in interactive mode, as if the
5615 variable is implied for this automatically spawned editor session.
5619 \*(BO When a message is edited while being composed,
5620 its header is included in the editable text.
5630 fields are accepted within the header, other fields are ignored.
5634 \*(BO When entering interactive mode \*(UA normally writes
5635 .Dq \&No mail for user
5636 and exits immediately if a mailbox is empty or doesn't exist.
5637 If this option is set \*(UA starts even with an empty or nonexistent
5638 mailbox (the latter behaviour furtherly depends upon
5644 Suggestion for the MIME encoding to use in outgoing text messages
5646 Valid values are the default
5647 .Ql quoted-printable ,
5652 may cause problems when transferring mail messages over channels that
5653 are not ESMTP (RFC 1869) compliant.
5654 If there is no need to encode a message,
5656 transfer mode is always used regardless of this variable.
5657 Binary data is always encoded as
5662 If defined, the first character of this option
5663 gives the character to use in place of
5666 .Sx "TILDE ESCAPES" .
5670 If not set then file and command pipeline targets are not allowed,
5671 and any such address will be filtered out, giving a warning message.
5672 If set without a value then all possible recipient address
5673 specifications will be accepted \(en see the section
5674 .Sx "On sending mail, and non-interactive mode"
5676 To accept them, but only in interactive mode, or when tilde commands
5677 were enabled explicitly by using one of the command line options
5681 set this to the (case-insensitive) value
5683 (note right now this is actually like setting
5684 .Ql restrict,-all,+name,+addr ) .
5686 In fact the value is interpreted as a comma-separated list of values.
5689 then the existence of disallowed specifications is treated as a hard
5690 send error instead of only filtering them out.
5691 The remaining values specify wether a specific type of recipient
5692 address specification is allowed (optionally indicated by a plus sign
5694 prefix) or disallowed (prefixed with a hyphen
5698 addresses all possible address specifications,
5702 command pipeline targets,
5704 plain user names and (MTA) aliases (\*(OB
5706 may be used as an alternative syntax to
5711 These kind of values are interpreted in the given order, so that
5712 .Ql restrict,\:fail,\:+file,\:-all,\:+addr
5713 will cause hard errors for any non-network address recipient address
5714 unless \*(UA is in interactive mode or has been started with the
5718 command line option; in the latter case(s) any address may be used, then.
5722 Unless this variable is set additional mail-transfer-agent (MTA)
5723 arguments from the command line, as can be given after a
5725 separator, are ignored due to safety reasons.
5726 However, if set to the special (case-insensitive) value
5728 then the presence of additional MTA arguments is treated as a hard
5729 error that causes \*(UA to exit with failure status.
5730 A lesser strict variant is the otherwise identical
5732 which does accept such arguments in interactive mode, or if tilde
5733 commands were enabled explicitly by using one of the command line options
5740 \*(RO Information on the features compiled into \*(UA \(en the content
5741 of this variable is identical to the output of the command
5746 \*(BO This option reverses the meanings of a set of reply commands,
5747 turning the lowercase variants, which by default address all recipients
5748 included in the header of a message
5749 .Pf ( Ic reply , respond , followup )
5750 into the uppercase variants, which by default address the sender only
5751 .Pf ( Ic Reply , Respond , Followup )
5754 .Ic replysender , respondsender , followupsender
5756 .Ic replyall , respondall , followupall
5757 are not affected by the current setting of
5762 .It Va file-hook-load-EXTENSION , file-hook-save-EXTENSION
5763 It is possible to install file hooks which will be used by the
5765 command in order to be able to transparently handle (through an
5766 intermediate temporary file) files with specific
5768 s: the variable values can include shell snippets and are expected to
5769 write data to standard output / read data from standard input,
5771 \*(ID The variables may not be changed while there is a mailbox
5773 .Bd -literal -offset indent
5774 set file-hook-load-xy='echo >&2 XY-LOAD; gzip -cd' \e
5775 file-hook-save-xy='echo >&2 XY-SAVE; gzip -c' \e
5776 record=+null-sent.xy
5781 The name of the directory to use for storing folders of messages.
5782 All folder names that begin with
5784 refer to files below it.
5785 The same special conventions as documented for the
5787 command may be used when specifying a new value for
5789 but be aware that the expansion is fully performed immediately.
5793 This variable can be set to the name of a
5795 macro which will be called whenever a
5798 The macro will also be invoked when new mail arrives,
5799 but message lists for commands executed from the macro
5800 only include newly arrived messages then.
5802 are activated by default in a folder hook, causing the covered settings
5803 to be reverted once the folder is left again.
5806 Macro behaviour, including option localization, will change in v15.
5807 Please be aware of that and possibly embed a version check in a resource
5811 .It Va folder-hook-FOLDER
5816 Unlike other folder specifications, the fully expanded name of a folder,
5817 without metacharacters, is used to avoid ambiguities.
5818 However, if the mailbox resides under
5822 specification is tried in addition, e.g., if
5826 (and thus relative to the user's home directory) then
5827 .Pa /home/usr1/mail/sent
5829 .Ql folder-hook-/home/usr1/mail/sent
5830 first, but then followed by
5831 .Ql folder-hook-+sent .
5835 \*(BO Controls wether a
5836 .Ql Mail-Followup-To:
5837 header is generated when sending messages to known mailing lists.
5839 .Va followup-to-honour
5841 .Ic mlist , mlsubscribe , reply
5846 .It Va followup-to-honour
5848 .Ql Mail-Followup-To:
5849 header is honoured when group-replying to a message via
5853 This is a quadoption; if set without a value it defaults to
5863 .It Va forward-as-attachment
5864 \*(BO Original messages are normally sent as inline text with the
5867 and only the first part of a multipart message is included.
5868 With this option messages are sent as unmodified MIME
5870 attachments with all of their parts included.
5874 The address (or a list of addresses) to put into the
5876 field of the message header, quoting RFC 5322:
5877 the author(s) of the message, that is, the mailbox(es) of the person(s)
5878 or system(s) responsible for the writing of the message.
5879 If replying to messages these addresses are handled as if they were in
5883 If the machine's hostname is not valid at the Internet (for example at
5884 a dialup machine) then either this variable or
5889 adds even more fine-tuning capabilities),
5893 contains more than one address,
5896 variable is required (according to the standard RFC 5322).
5900 \*(BO When replying to or forwarding a message \*(UA normally removes
5901 the comment and name parts of email addresses.
5902 If this variable is set such stripping is not performed,
5903 and comments, names etc. are retained.
5907 The string to put before the text of a message with the
5911 .Va forward-as-attachment
5914 .Dq -------- Original Message --------
5915 if unset; No heading is put if it is set to the empty string.
5919 \*(BO Causes the header summary to be written at startup and after
5920 commands that affect the number of messages or the order of messages in
5921 the current folder; enabled by default.
5922 The command line option
5930 A format string to use for the summary of
5932 similar to the ones used for
5935 Format specifiers in the given string start with a percent character
5937 and may be followed by an optional decimal number indicating the field
5938 width \(em if that is negative, the field is to be left-aligned.
5939 Valid format specifiers are:
5942 .Bl -tag -compact -offset indent -width "_%%_"
5944 A plain percent character.
5947 a space character but for the current message
5949 for which it expands to
5953 a space character but for the current message
5955 for which it expands to
5958 \*(OP The spam score of the message, as has been classified via the
5961 Shows only a replacement character if there is no spam support.
5963 Message attribute character (status flag); the actual content can be
5967 The date when the message was received, or the date found in the
5971 variable is set (optionally to a date display format string).
5973 The indenting level in threaded mode.
5975 The address of the message sender.
5977 The message thread tree structure.
5978 (Note that this format doesn't support a field width.)
5980 The number of lines of the message, if available.
5984 The number of octets (bytes) in the message, if available.
5986 Message subject (if any).
5988 Message subject (if any) in double quotes.
5990 Message recipient flags: is the addressee of the message a known or
5991 subscribed mailing list \(en see
5996 The position in threaded/sorted order.
6000 .Ql %>\&%a\&%m\ %-18f\ %16d\ %4l/%\-5o\ %i%-s ,
6002 .Ql %>\&%a\&%m\ %20-f\ \ %16d\ %3l/%\-5o\ %i%-S
6013 .It Va headline-bidi
6014 Bidirectional text requires special treatment when displaying headers,
6015 because numbers (in dates or for file sizes etc.) will not affect the
6016 current text direction, in effect resulting in ugly line layouts when
6017 arabic or other right-to-left text is to be displayed.
6018 On the other hand only a minority of terminals is capable to correctly
6019 handle direction changes, so that user interaction is necessary for
6021 Note that extended host system support is required nonetheless, e.g.,
6022 detection of the terminal character set is one precondition;
6023 and this feature only works in an Unicode (i.e., UTF-8) locale.
6025 In general setting this variable will cause \*(UA to encapsulate text
6026 fields that may occur when displaying
6028 (and some other fields, like dynamic expansions in
6030 with special Unicode control sequences;
6031 it is possible to fine-tune the terminal support level by assigning
6033 no value (or any value other than
6038 will make \*(UA assume that the terminal is capable to properly deal
6039 with Unicode version 6.3, in which case text is embedded in a pair of
6040 U+2068 (FIRST STRONG ISOLATE) and U+2069 (POP DIRECTIONAL ISOLATE)
6042 In addition no space on the line is reserved for these characters.
6044 Weaker support is chosen by using the value
6046 (Unicode 6.3, but reserve the room of two spaces for writing the control
6047 sequences onto the line).
6052 select Unicode 1.1 support (U+200E, LEFT-TO-RIGHT MARK); the latter
6053 again reserves room for two spaces in addition.
6057 \*(OP If a line editor is available then this can be set to
6058 name the (expandable) path of the location of a permanent history file.
6061 .It Va history-gabby
6062 \*(BO\*(OP Add more entries to the history as is normally done.
6065 .It Va history-gabby-persist
6066 \*(BO\*(OP \*(UA's own MLE will not save the additional
6068 entries in persistent storage unless this variable is set.
6069 On the other hand it will not loose the knowledge of wether a persistent
6070 entry was gabby or not.
6076 \*(OP If a line editor is available this value restricts the
6077 amount of history entries that are saved into a set and valid
6079 A value of less than 0 disables this feature;
6080 note that loading and incorporation of
6082 upon program startup can also be suppressed by doing this.
6083 An unset or invalid value, or 0, causes a default value to be used.
6084 Dependent on the available line editor this will also define the
6085 number of history entries in memory;
6086 it is also editor-specific wether runtime updates of this value will be
6091 \*(BO This option is used to hold messages in the system mailbox,
6092 and it is set by default.
6096 Use this string as hostname when expanding local addresses instead of
6097 the value obtained from
6108 transport is not used then it is normally the responsibility of the MTA
6109 to create these fields, \*(IN in conjunction with
6113 also influences the results;
6114 you should produce some test messages with the desired combination of
6123 \*(BO\*(OP Can be used to turn off the automatic conversion of domain
6124 names according to the rules of IDNA (internationalized domain names
6126 Since the IDNA code assumes that domain names are specified with the
6128 character set, an UTF-8 locale charset is required to represent all
6129 possible international domain names (before conversion, that is).
6133 \*(BO Ignore interrupt signals from the terminal while entering
6134 messages; instead echo them as
6136 characters and discard the current line.
6140 \*(BO Ignore end-of-file conditions
6141 .Pf ( Ql control-D )
6142 in compose mode on message input and in interactive command input.
6143 If set an interactive command input session can only be left by
6144 explicitly using one of the commands
6148 and message input in compose mode can only be terminated by entering
6151 on a line by itself or by using the
6153 .Sx "TILDE ESCAPES" ;
6155 overrides a setting of
6167 option for indenting messages,
6168 in place of the normal tabulator character
6170 which is the default.
6171 Be sure to quote the value if it contains spaces or tabs.
6175 \*(BO If set, an empty mailbox file is not removed.
6176 This may improve the interoperability with other mail user agents
6177 when using a common folder directory, and prevents malicious users
6178 from creating fake mailboxes in a world-writable spool directory.
6179 Note this only applies to local regular (MBOX) files, other mailbox
6180 types will never be removed.
6183 .It Va keep-content-length
6184 \*(BO When (editing messages and) writing
6186 mailbox files \*(UA can be told to keep the
6190 header fields that some MUAs generate by setting this variable.
6191 Since \*(UA does neither use nor update these non-standardized header
6192 fields (which in itself shows one of their conceptual problems),
6193 stripping them should increase interoperability in between MUAs that
6194 work with with same mailbox files.
6195 Note that, if this is not set but
6196 .Va writebackedited ,
6197 as below, is, a possibly performed automatic stripping of these header
6198 fields already marks the message as being modified.
6202 \*(BO When a message is saved it is usually discarded from the
6203 originating folder when \*(UA is quit.
6204 Setting this option causes all saved message to be retained.
6207 .It Va line-editor-disable
6208 \*(BO Turn off any enhanced line editing capabilities (see
6209 .Sx "On terminal control and line editor"
6214 \*(BO When a message is replied to and this variable is set,
6215 it is marked as having been answered.
6216 This mark has no technical meaning in the mail system;
6217 it just causes messages to be marked in the header summary,
6218 and makes them specially addressable.
6222 \*(BO \*(UA generates and expects fully RFC 4155 compliant MBOX text
6224 Messages which are fetched over the network or from within already
6225 existing Maildir (or any non-MBOX) mailboxes may require so-called
6227 quoting (insertion of additional
6229 characters to prevent line content misinterpretation) to be applied in
6230 order to be storable in MBOX mailboxes, however, dependent on the
6231 circumspection of the message producer.
6232 (E.g., \*(UA itself will, when newly generating messages, choose a
6233 .Pf Content-Transfer- Va encoding
6234 that prevents the necessity for such quoting \(en a necessary
6235 precondition to ensure message checksums won't change.)
6237 By default \*(UA will perform this
6239 quoting in a way that results in a MBOX file that is compatible with
6240 the POSIX MBOX layout, which means that, in order not to exceed the
6241 capabilities of simple applications, many more
6243 lines get quoted (thus modified) than necessary according to RFC 4155.
6244 Set this option to instead generate MBOX files which comply to RFC 4155.
6248 \*(BO Internal development variable.
6251 .It Va message-id-disable
6252 \*(BO By setting this option the generation of
6254 can be completely suppressed, effectively leaving this task up to the
6255 mail-transfer-agent (MTA) or the SMTP server.
6256 (According to RFC 5321 your SMTP server is not required to add this
6257 field by itself, so you should ensure that it accepts messages without a
6261 .It Va message-inject-head
6262 A string to put at the beginning of each new message.
6263 The escape sequences tabulator
6270 .It Va message-inject-tail
6271 A string to put at the end of each new message.
6272 The escape sequences tabulator
6280 \*(BO Usually, when an
6282 expansion contains the sender, the sender is removed from the expansion.
6283 Setting this option suppresses these removals.
6288 option to be passed to mail-transfer-agents (MTAs);
6289 though most of the modern MTAs don't (no longer) document this flag, no
6290 MTA is known which doesn't support it (for historical compatibility).
6293 .It Va mime-allow-text-controls
6294 \*(BO When sending messages, each part of the message is MIME-inspected
6295 in order to classify the
6298 .Ql Content-Transfer-Encoding:
6301 that is required to send this part over mail transport, i.e.,
6302 a computation rather similar to what the
6304 command produces when used with the
6308 This classification however treats text files which are encoded in
6309 UTF-16 (seen for HTML files) and similar character sets as binary
6310 octet-streams, forcefully changing any
6315 .Ql application/octet-stream :
6316 If that actually happens a yet unset charset MIME parameter is set to
6318 effectively making it impossible for the receiving MUA to automatically
6319 interpret the contents of the part.
6321 If this option is set, and the data was unambiguously identified as text
6322 data at first glance (by a
6326 file extension), then the original
6328 will not be overwritten.
6331 .It Va mime-alternative-favour-rich
6332 \*(BO If this variable is set then rich MIME alternative parts (e.g.,
6333 HTML) will be preferred in favour of included plain text versions when
6334 displaying messages, provided that a handler exists which produces
6335 output that can be (re)integrated into \*(UA's normal visual display.
6336 (E.g., at the time of this writing some newsletters ship their full
6337 content only in the rich HTML part, whereas the plain text part only
6338 contains topic subjects.)
6341 .It Va mime-counter-evidence
6344 field is used to decide how to handle MIME parts.
6345 Some MUAs however don't use
6347 or a similar mechanism to correctly classify content, but simply specify
6348 .Ql application/octet-stream ,
6349 even for plain text attachments like
6351 If this variable is set then \*(UA will try to classify such MIME
6352 message parts on its own, if possible, for example via a possibly
6353 existent attachment filename.
6354 A non-empty value may also be given, in which case a number is expected,
6355 actually a carrier of bits.
6356 Creating the bit-carrying number is a simple addition:
6357 .Bd -literal -offset indent
6358 ? !echo Value should be set to $((2 + 4 + 8))
6359 Value should be set to 14
6362 .Bl -bullet -compact
6364 If bit two is set (2) then the detected
6366 content-type will be carried along with the message and be used for
6368 .Va pipe-TYPE/SUBTYPE
6369 is responsible for the MIME part, shall that question arise;
6370 when displaying such a MIME part the part-info will indicate the
6371 overridden content-type by showing a plus-sign
6374 If bit three is set (4) then the counter-evidence is always produced
6375 and a positive result will be used as the MIME type, even forcefully
6376 overriding the parts given MIME type.
6378 If bit four is set (8) then as a last resort the actual content of
6379 .Ql application/octet-stream
6380 parts will be inspected, so that data which looks like plain text can be
6385 .It Va mimetypes-load-control
6386 This option can be used to control which of the
6388 databases are loaded by \*(UA, as furtherly described in the section
6389 .Sx "The mime.types files" .
6392 is part of the option value, then the user's personal
6394 file will be loaded (if it exists); likewise the letter
6396 controls loading of the system wide
6397 .Pa /etc/mime.types ;
6398 directives found in the user file take precedence, letter matching is
6400 If this option is not set \*(UA will try to load both files.
6401 Incorporation of the \*(UA-builtin MIME types cannot be suppressed,
6402 but they will be matched last.
6404 More sources can be specified by using a different syntax: if the
6405 value string contains an equals sign
6407 then it is instead parsed as a comma-separated list of the described
6410 pairs; the given filenames will be expanded and loaded, and their
6411 content may use the extended syntax that is described in the section
6412 .Sx "The mime.types files" .
6413 Directives found in such files always take precedence (are prepended to
6414 the MIME type cache).
6417 .It Va NAIL_EXTRA_RC
6418 The name of an optional startup file to be read last.
6419 This variable has an effect only if it is set in any of the
6420 .Sx "Resource files" ,
6421 it is not imported from the environment.
6422 Use this file for commands that are not understood by other POSIX
6427 .It Va netrc-lookup-USER@HOST , netrc-lookup-HOST , netrc-lookup
6428 \*(BO\*(IN\*(OP Used to control usage of the users
6430 file for lookup of account credentials, as documented in the section
6431 .Sx "On URL syntax and credential lookup"
6435 .Sx "The .netrc file"
6436 documents the file format.
6440 If this variable has the value
6442 newly created local folders will be in Maildir format.
6446 Checks for new mail in the current folder each time the prompt is shown.
6447 A Maildir folder must be re-scanned to determine if new mail has arrived.
6448 If this variable is set to the special value
6450 then a Maildir folder will not be rescanned completely, but only
6451 timestamp changes are detected.
6455 .It Va on-compose-enter , on-compose-leave
6456 \*(ID Macro hooks which will be executed before compose mode is
6457 entered, and after composing has been finished, respectively.
6458 Please note that this interface is very likely to change in v15, and
6459 should therefore possibly even be seen as experimental.
6461 are by default enabled for these hooks, causing any setting to be
6462 forgotten after the message has been sent.
6463 The following variables will be set temporarily during execution of the
6466 .Bl -tag -compact -width ".It Va compose_subject"
6469 .It Va compose-sender
6471 .It Va compose-to , compose-cc , compose-bcc
6472 The list of receiver addresses as a space-separated list.
6473 .It Va compose-subject
6479 \*(BO Causes the filename given in the
6482 and the sender-based filenames for the
6486 commands to be interpreted relative to the directory given in the
6488 variable rather than to the current directory,
6489 unless it is set to an absolute pathname.
6493 \*(BO If set, each message feed through the command given for
6495 is followed by a formfeed character
6499 .It Va password-USER@HOST , password-HOST , password
6500 \*(IN Variable chain that sets a password, which is used in case none has
6501 been given in the protocol and account-specific URL;
6502 as a last resort \*(UA will ask for a password on the user's terminal if
6503 the authentication method requires a password.
6504 Specifying passwords in a startup file is generally a security risk;
6505 the file should be readable by the invoking user only.
6507 .It Va password-USER@HOST
6508 \*(OU (see the chain above for \*(IN)
6509 Set the password for
6513 If no such variable is defined for a host,
6514 the user will be asked for a password on standard input.
6515 Specifying passwords in a startup file is generally a security risk;
6516 the file should be readable by the invoking user only.
6520 \*(BO Send messages to the
6522 command without performing MIME and character set conversions.
6526 .It Va pipe-TYPE/SUBTYPE
6527 When a MIME message part of type
6529 (case-insensitive) is displayed or quoted,
6530 its text is filtered through the value of this variable interpreted as
6534 forces interpretation of the message part as plain text, e.g.,
6535 .Ql set pipe-application/xml=@
6536 will henceforth display XML
6538 (The same could also be achieved by adding a MIME type marker with the
6541 And \*(OPally MIME type handlers may be defined via
6542 .Sx "The Mailcap files"
6543 \(em corresponding flag strings are shown in parenthesis below.)
6548 can in fact be used to adjust usage and behaviour of a following shell
6549 command specification by appending trigger characters to it, e.g., the
6550 following hypothetical command specification could be used:
6551 .Bd -literal -offset indent
6552 set pipe-X/Y="@*!++=@vim ${NAIL_FILENAME_TEMPORARY}"
6556 .Bl -tag -compact -width ".It Ql __"
6558 Simply by using the special
6560 prefix the MIME type (shell command) handler will only be invoked to
6561 display or convert the MIME part if the message is addressed directly
6562 and alone by itself.
6563 Use this trigger to disable this and always invoke the handler
6564 .Pf ( Cd x-mailx-always ) .
6567 If set the handler will not be invoked when a message is to be quoted,
6568 but only when it will be displayed
6569 .Pf ( Cd x-mailx-noquote ) .
6572 The command will be run asynchronously, i.e., without blocking \*(UA,
6573 which may be a handy way to display a, e.g., PDF file while also
6574 continuing to read the mail message
6575 .Pf ( Cd x-mailx-async ) .
6576 Asynchronous execution implies
6580 The command must be run on an interactive terminal, \*(UA will
6581 temporarily release the terminal to it
6582 .Pf ( Cd needsterminal ) .
6583 This flag is mutual exclusive with
6585 will only be used in interactive mode and implies
6589 Request creation of a zero-sized temporary file, the absolute pathname
6590 of which will be made accessable via the environment variable
6591 .Ev NAIL_FILENAME_TEMPORARY
6592 .Pf ( Cd x-mailx-tmpfile ) .
6593 If this trigger is given twice then the file will be unlinked
6594 automatically by \*(UA when the command loop is entered again at latest
6595 .Pf ( Cd x-mailx-tmpfile-unlink ) .
6596 (Don't use this for asynchronous handlers.)
6599 Normally the MIME part content is passed to the handler via standard
6600 input; if this flag is set then the data will instead be written into
6601 .Ev NAIL_FILENAME_TEMPORARY
6602 .Pf ( Cd x-mailx-tmpfile-fill ) ,
6603 the creation of which is implied; note however that in order to cause
6604 deletion of the temporary file you still have to use two plus signs
6609 To avoid ambiguities with normal shell command content you can use
6610 another at-sign to forcefully terminate interpretation of remaining
6612 (Any character not in this list will have the same effect.)
6616 Some information about the MIME part to be displayed is embedded into
6617 the environment of the shell command:
6620 .Bl -tag -compact -width ".It Ev _AIL__ILENAME__ENERATED"
6623 The MIME content-type of the part, if known, the empty string otherwise.
6626 .It Ev NAIL_CONTENT_EVIDENCE
6628 .Va mime-counter-evidence
6629 includes the carry-around-bit (2), then this will be set to the detected
6630 MIME content-type; not only then identical to
6631 .Ev \&\&NAIL_CONTENT
6635 .It Ev NAIL_FILENAME
6636 The filename, if any is set, the empty string otherwise.
6639 .It Ev NAIL_FILENAME_GENERATED
6643 .It Ev NAIL_FILENAME_TEMPORARY
6644 If temporary file creation has been requested through the command prefix
6645 this variable will be set and contain the absolute pathname of the
6650 The temporary directory that \*(UA uses.
6651 Usually identical to
6653 but guaranteed to be set and usable by child processes;
6654 to ensure the latter condition for
6661 .It Va pipe-EXTENSION
6662 This is identical to
6663 .Va pipe-TYPE/SUBTYPE
6666 (normalized to lowercase using character mappings of the ASCII charset)
6667 names a file extension, e.g.,
6669 Handlers registered using this method take precedence.
6672 .It Va pop3-auth-USER@HOST , pop3-auth-HOST , pop3-auth
6673 \*(OP\*(IN Variable chain that sets the POP3 authentication method.
6674 The only possible value as of now is
6676 which is thus the default.
6679 .Mx Va pop3-bulk-load
6680 .It Va pop3-bulk-load-USER@HOST , pop3-bulk-load-HOST , pop3-bulk-load
6681 \*(BO\*(OP When accessing a POP3 server \*(UA loads the headers of
6682 the messages, and only requests the message bodies on user request.
6683 For the POP3 protocol this means that the message headers will be
6685 If this option is set then \*(UA will download only complete messages
6686 from the given POP3 server(s) instead.
6688 .Mx Va pop3-keepalive
6689 .It Va pop3-keepalive-USER@HOST , pop3-keepalive-HOST , pop3-keepalive
6690 \*(OP POP3 servers close the connection after a period of inactivity;
6691 the standard requires this to be at least 10 minutes,
6692 but practical experience may vary.
6693 Setting this variable to a numeric value greater than
6697 command to be sent each value seconds if no other operation is performed.
6700 .It Va pop3-no-apop-USER@HOST , pop3-no-apop-HOST , pop3-no-apop
6701 \*(BO\*(OP Unless this variable is set the
6703 authentication method will be used when connecting to a POP3 server that
6707 is that the password is not sent in clear text over the wire and that
6708 only a single packet is sent for the user/password tuple.
6710 .Va pop3-no-apop-HOST
6713 .Mx Va pop3-use-starttls
6714 .It Va pop3-use-starttls-USER@HOST , pop3-use-starttls-HOST , pop3-use-starttls
6715 \*(BO\*(OP Causes \*(UA to issue a
6717 command to make an unencrypted POP3 session SSL/TLS encrypted.
6718 This functionality is not supported by all servers,
6719 and is not used if the session is already encrypted by the POP3S method.
6721 .Va pop3-use-starttls-HOST
6725 .It Va print-alternatives
6726 \*(BO When a MIME message part of type
6727 .Ql multipart/alternative
6728 is displayed and it contains a subpart of type
6730 other parts are normally discarded.
6731 Setting this variable causes all subparts to be displayed,
6732 just as if the surrounding part was of type
6733 .Ql multipart/mixed .
6737 The string shown when a command is accepted.
6738 Prompting may be prevented by setting this to the null string
6740 .Pf no Va prompt ) .
6741 If a value is assigned the following \*(UA specific additional sequences
6748 is set, in which case it expands to
6752 is the default value of
6755 which will expand to
6757 if the last command failed and to
6761 which will expand to the name of the currently active
6763 if any, and to the empty string otherwise, and
6765 which will expand to the name of the currently active mailbox.
6766 (Note that the prompt buffer is size-limited, excess is cut off.)
6772 to encapsulate the expansions of the
6776 escape sequences as necessary to correctly display bidirectional text,
6777 this is not true for the final string that makes up
6779 as such, i.e., real BIDI handling is not supported.
6783 \*(BO Suppresses the printing of the version when first invoked.
6787 If set, \*(UA starts a replying message with the original message
6788 prefixed by the value of the variable
6790 Normally, a heading consisting of
6791 .Dq Fromheaderfield wrote:
6792 is put before the quotation.
6797 variable, this heading is omitted.
6800 is assigned, the headers selected by the
6801 .Ic ignore Ns / Ns Ic retain
6802 commands are put above the message body,
6805 acts like an automatic
6811 is assigned, all headers are put above the message body and all MIME
6812 parts are included, making
6814 act like an automatic
6817 .Va quote-as-attachment .
6820 .It Va quote-as-attachment
6821 \*(BO Add the original message in its entirety as a
6823 MIME attachment when replying to a message.
6824 Note this works regardless of the setting of
6829 \*(OP Can be set in addition to
6831 Setting this turns on a more fancy quotation algorithm in that leading
6832 quotation characters are compressed and overlong lines are folded.
6834 can be set to either one or two (space separated) numeric values,
6835 which are interpreted as the maximum (goal) and the minimum line length,
6836 respectively, in a spirit rather equal to the
6838 program, but line-, not paragraph-based.
6839 If not set explicitly the minimum will reflect the goal algorithmically.
6840 The goal can't be smaller than the length of
6842 plus some additional pad.
6843 Necessary adjustments take place silently.
6846 .It Va recipients-in-cc
6847 \*(BO On group replies, specify only the sender of the original mail in
6849 and mention the other recipients in the secondary
6851 By default all recipients of the original mail will be addressed via
6856 If defined, gives the pathname of the folder used to record all outgoing
6858 If not defined, then outgoing mail is not saved.
6859 When saving to this folder fails the message is not sent,
6860 but instead saved to
6864 .It Va record-resent
6865 \*(BO If both this variable and the
6872 commands save messages to the
6874 folder as it is normally only done for newly composed messages.
6877 .It Va reply-in-same-charset
6878 \*(BO If this variable is set \*(UA first tries to use the same
6879 character set of the original message for replies.
6880 If this fails, the mechanism described in
6881 .Sx "Character sets"
6882 is evaluated as usual.
6885 .It Va reply_strings
6886 Can be set to a comma-separated list of (case-insensitive according to
6887 ASCII rules) strings which shall be recognized in addition to the
6890 reply message indicators \(en builtin are
6892 which is mandated by RFC 5322, as well as the german
6897 A list of addresses to put into the
6899 field of the message header.
6900 Members of this list are handled as if they were in the
6905 .It Va reply-to-honour
6908 header is honoured when replying to a message via
6912 This is a quadoption; if set without a value it defaults to
6916 .It Va rfc822-body-from_
6917 \*(BO This variable can be used to force displaying a so-called
6919 line for messages that are embedded into an envelope mail via the
6921 MIME mechanism, for more visual convenience.
6925 \*(BO Enable saving of (partial) messages in
6927 upon interrupt or delivery error.
6931 When \*(UA initially displays the message headers it determines the
6932 number to display by looking at the speed of the terminal.
6933 The faster the terminal, the more will be shown.
6934 This option specifies the number to use and overrides the calculation.
6935 This number is also used for scrolling with the
6938 Overall screen dimensions and pager usage is influenced by the
6939 environment variables
6947 .It Va searchheaders
6948 \*(BO Expand message-list specifiers in the form
6950 to all messages containing the substring
6954 The string search is case insensitive.
6958 \*(OP A comma-separated list of character set names that can be used in
6959 outgoing internet mail.
6960 The value of the variable
6962 is automatically appended to this list of character-sets.
6963 If no character set conversion capabilities are compiled into \*(UA then
6964 the only supported charset is
6967 .Va sendcharsets-else-ttycharset
6968 and refer to the section
6969 .Sx "Character sets"
6970 for the complete picture of character set conversion in \*(UA.
6973 .It Va sendcharsets-else-ttycharset
6974 \*(BO\*(OP If this variable is set, but
6976 is not, then \*(UA acts as if
6978 had been set to the value of the variable
6980 In effect this combination passes through the message data in the
6981 character set of the current locale (given that
6983 hasn't been set manually), i.e., without converting it to the
6985 fallback character set.
6986 Thus, mail message text will be in ISO-8859-1 encoding when send from
6987 within a ISO-8859-1 locale, and in UTF-8 encoding when send from within
6989 If no character set conversion capabilities are available in \*(UA then
6990 the only supported character set is
6995 An address that is put into the
6997 field of outgoing messages, quoting RFC 5322: the mailbox of the agent
6998 responsible for the actual transmission of the message.
6999 This field should normally not be used unless the
7001 field contains more than one address, on which case it is required.
7004 address is handled as if it were in the
7010 To use an alternate mail transport agent (MTA),
7011 set this option to the full pathname of the program to use.
7012 It may be necessary to set
7013 .Va sendmail-progname
7016 The MTA will be passed command line arguments from several possible
7017 sources: from the variable
7018 .Va sendmail-arguments
7019 if set, from the command line if given and the variable
7022 Argument processing of the MTA will be terminated with a
7026 The otherwise occurring implicit usage of the following MTA command line
7027 arguments can be disabled by setting the boolean option
7028 .Va sendmail-no-default-arguments
7029 (which will also disable passing
7033 (for not treating a line with only a dot
7035 character as the end of input),
7043 option is set); in conjunction with the
7045 command line option \*(UA will also pass
7051 .It Va sendmail-arguments
7052 Arguments to pass through to the Mail-Transfer-Agent can be given via
7054 The content of this variable will be split up in a vector of arguments
7055 which will be joined onto other possible MTA options:
7057 .Dl set sendmail-arguments='-t -X \&"/tmp/my log\&"'
7060 .It Va sendmail-no-default-arguments
7061 \*(BO Unless this option is set \*(UA will pass some well known
7062 standard command line options to the defined
7064 program, see there for more.
7067 .It Va sendmail-progname
7068 Many systems use a so-called
7070 environment to ensure compatibility with
7072 This works by inspecting the name that was used to invoke the mail
7074 If this variable is set then the mailwrapper (the program that is
7075 actually executed when calling
7077 will treat its contents as that name.
7083 \*(BO When sending a message wait until the MTA (including the builtin
7084 SMTP one) exits before accepting further commands.
7086 with this variable set errors reported by the MTA will be recognizable!
7087 If the MTA returns a non-zero exit status,
7088 the exit status of \*(UA will also be non-zero.
7092 \*(BO Setting this option causes \*(UA to start at the last message
7093 instead of the first one when opening a mail folder.
7097 \*(BO Causes \*(UA to use the sender's real name instead of the plain
7098 address in the header field summary and in message specifications.
7102 \*(BO Causes the recipient of the message to be shown in the header
7103 summary if the message was sent by the user.
7107 A string for use with the
7113 A string for use with the
7119 Must correspond to the name of a readable file if set.
7120 The file's content is then appended to each singlepart message
7121 and to the first part of each multipart message.
7122 Be warned that there is no possibility to edit the signature for an
7126 .It Va skipemptybody
7127 \*(BO If an outgoing message does not contain any text in its first or
7128 only message part, do not send it but discard it silently (see also the
7134 \*(OP Specifies a directory with CA certificates in PEM (Privacy
7135 Enhanced Mail) format for verification of S/MIME signed messages.
7138 .It Va smime-ca-file
7139 \*(OP Specifies a file with CA certificates in PEM format for
7140 verification of S/MIME signed messages.
7143 .It Va smime-cipher-USER@HOST , smime-cipher
7144 \*(OP Specifies the cipher to use when generating S/MIME encrypted
7145 messages (for the specified account).
7146 RFC 5751 mandates a default of
7149 Possible values are (case-insensitive and) in decreasing cipher strength:
7157 (DES EDE3 CBC, 168 bits; default if
7159 isn't available) and
7163 The actually available cipher algorithms depend on the cryptographic
7164 library that \*(UA uses.
7165 \*(OP Support for more cipher algorithms may be available through
7166 dynamic loading via, e.g.,
7167 .Xr EVP_get_cipherbyname 3
7168 (OpenSSL) if \*(UA has been compiled to support this.
7171 .It Va smime-crl-dir
7172 \*(OP Specifies a directory that contains files with CRLs in PEM format
7173 to use when verifying S/MIME messages.
7176 .It Va smime-crl-file
7177 \*(OP Specifies a file that contains a CRL in PEM format to use when
7178 verifying S/MIME messages.
7181 .It Va smime-encrypt-USER@HOST
7182 \*(OP If this variable is set, messages send to the given receiver are
7183 encrypted before sending.
7184 The value of the variable must be set to the name of a file that
7185 contains a certificate in PEM format.
7187 If a message is sent to multiple recipients,
7188 each of them for whom a corresponding variable is set will receive an
7189 individually encrypted message;
7190 other recipients will continue to receive the message in plain text
7192 .Va smime-force-encryption
7194 It is recommended to sign encrypted messages, i.e., to also set the
7199 .It Va smime-force-encryption
7200 \*(BO\*(OP Causes \*(UA to refuse sending unencrypted messages.
7203 .It Va smime-no-default-ca
7204 \*(BO\*(OP Don't load default CA locations when verifying S/MIME signed
7209 \*(BO\*(OP S/MIME sign outgoing messages with the user's private key
7210 and include the user's certificate as a MIME attachment.
7211 Signing a message enables a recipient to verify that the sender used
7212 a valid certificate,
7213 that the email addresses in the certificate match those in the message
7214 header and that the message content has not been altered.
7215 It does not change the message text,
7216 and people will be able to read the message as usual.
7218 .Va smime-sign-cert , smime-sign-include-certs
7220 .Va smime-sign-message-digest .
7222 .Mx Va smime-sign-cert
7223 .It Va smime-sign-cert-USER@HOST , smime-sign-cert
7224 \*(OP Points to a file in PEM format.
7225 For the purpose of signing and decryption this file needs to contain the
7226 user's private key as well as his certificate.
7230 is always derived from the value of
7232 (or, if that contains multiple addresses,
7234 For the purpose of encryption the recipient's public encryption key
7235 (certificate) is expected; the command
7237 can be used to save certificates of signed messages (the section
7238 .Sx "Signed and encrypted messages with S/MIME"
7239 gives some details).
7240 This mode of operation is usually driven by the specialized form.
7242 When decrypting messages the account is derived from the recipient
7247 of the message, which are searched for addresses for which such
7249 \*(UA always uses the first address that matches,
7250 so if the same message is sent to more than one of the user's addresses
7251 using different encryption keys, decryption might fail.
7253 .Mx Va smime-sign-include-certs
7254 .It Va smime-sign-include-certs-USER@HOST , smime-sign-include-certs
7255 \*(OP If used, this is supposed to a consist of a comma-separated list
7256 of files, each of which containing a single certificate in PEM format to
7257 be included in the S/MIME message in addition to the
7260 This is most useful for long certificate chains if it is desired to aid
7261 the receiving party's verification process.
7262 Note that top level certificates may also be included in the chain but
7263 don't play a role for verification.
7265 .Va smime-sign-cert .
7266 Remember that for this
7268 refers to the variable
7270 (or, if that contains multiple addresses,
7273 .Mx Va smime-sign-message-digest
7274 .It Va smime-sign-message-digest-USER@HOST , smime-sign-message-digest
7275 \*(OP Specifies the message digest to use when signing S/MIME messages.
7276 RFC 5751 mandates a default of
7278 Possible values are (case-insensitive and) in decreasing cipher strength:
7286 The actually available message digest algorithms depend on the
7287 cryptographic library that \*(UA uses.
7288 \*(OP Support for more message digest algorithms may be available
7289 through dynamic loading via, e.g.,
7290 .Xr EVP_get_digestbyname 3
7291 (OpenSSL) if \*(UA has been compiled to support this.
7292 Remember that for this
7294 refers to the variable
7296 (or, if that contains multiple addresses,
7302 \*(OP Normally \*(UA invokes the program defined via
7304 to transfer messages, as described in
7305 .Sx "On sending mail, and non-interactive mode" .
7308 variable will instead cause SMTP network connections be made to the
7309 server specified therein in order to directly submit the message.
7310 \*(UA knows about three different
7311 .Dq SMTP protocols :
7313 .Bl -bullet -compact
7315 The plain SMTP protocol (RFC 5321) that normally lives on the
7316 server port 25 and requires setting the
7317 .Va smtp-use-starttls
7318 variable to enter a SSL/TLS encrypted session state.
7319 Assign a value like \*(IN
7320 .Ql [smtp://][user[:password]@]server[:port]
7322 .Ql [smtp://]server[:port] )
7323 to choose this protocol.
7325 Then the so-called SMTPS which is supposed to live on server port 465
7326 and is automatically SSL/TLS secured.
7327 Unfortunately it never became a standardized protocol and may thus not
7328 be supported by your hosts network service database
7329 \(en in fact the port number has already been reassigned to other
7332 SMTPS is nonetheless a commonly offered protocol and thus can be
7333 chosen by assigning a value like \*(IN
7334 .Ql smtps://[user[:password]@]server[:port]
7336 .Ql smtps://server[:port] ) ;
7337 due to the mentioned problems it is usually necessary to explicitly
7342 Finally there is the SUBMISSION protocol (RFC 6409), which usually
7343 lives on server port 587 and is practically identically to the SMTP
7344 protocol from \*(UA's point of view beside that; it requires setting the
7345 .Va smtp-use-starttls
7346 variable to enter a SSL/TLS secured session state.
7347 Assign a value like \*(IN
7348 .Ql submission://[user[:password]@]server[:port]
7350 .Ql submission://server[:port] ) .
7353 For more on credentials etc. please see
7354 .Sx "On URL syntax and credential lookup" .
7355 The SMTP transfer is executed in a child process, which runs
7356 asynchronously unless either the
7361 If it receives a TERM signal, it will abort and save the message to
7366 .It Va smtp-auth-USER@HOST , smtp-auth-HOST , smtp-auth
7367 \*(OP Variable chain that sets the SMTP authentication method.
7374 as well as the \*(OPal methods
7380 method doesn't need any user credentials,
7382 requires a user name and all other methods require a user name and
7390 .Va smtp-auth-password
7392 .Va smtp-auth-user ) .
7397 .Va smtp-auth-USER@HOST :
7398 may override dependend on sender address in the variable
7401 .It Va smtp-auth-password
7402 \*(OP\*(OU Sets the global fallback password for SMTP authentication.
7403 If the authentication method requires a password, but neither
7404 .Va smtp-auth-password
7406 .Va smtp-auth-password-USER@HOST
7408 \*(UA will ask for a password on the user's terminal.
7410 .It Va smtp-auth-password-USER@HOST
7412 .Va smtp-auth-password
7413 for specific values of sender addresses, dependent upon the variable
7416 .It Va smtp-auth-user
7417 \*(OP\*(OU Sets the global fallback user name for SMTP authentication.
7418 If the authentication method requires a user name, but neither
7421 .Va smtp-auth-user-USER@HOST
7423 \*(UA will ask for a user name on the user's terminal.
7425 .It Va smtp-auth-user-USER@HOST
7428 for specific values of sender addresses, dependent upon the variable
7432 .It Va smtp-hostname
7433 \*(IN Normally \*(UA uses the variable
7435 to derive the necessary
7437 information to issue a
7442 can be used to use the
7444 from the SMTP account
7451 from the content of this variable (or, if that is the empty string,
7453 or the local hostname as a last resort).
7454 This often allows using an address that is itself valid but hosted by
7455 a provider other than which (in
7457 is about to send the message.
7458 Setting this variable also influences the generated
7461 .Mx Va smtp-use-starttls
7462 .It Va smtp-use-starttls-USER@HOST , smtp-use-starttls-HOST , smtp-use-starttls
7463 \*(BO\*(OP Causes \*(UA to issue a
7465 command to make an SMTP session SSL/TLS encrypted, i.e., to enable
7466 transport layer security.
7470 .It Va spam-interface
7471 \*(OP In order to use any of the spam-related commands (like, e.g.,
7473 the desired spam interface must be defined by setting this variable.
7474 Please refer to the manual section
7476 for the complete picture of spam handling in \*(UA.
7477 All or none of the following interfaces may be available:
7479 .Bl -tag -width ".It Ql _ilte_"
7485 .Pf ( Lk http://spamassassin.apache.org SpamAssassin )
7487 Different to the generic filter interface \*(UA will automatically add
7488 the correct arguments for a given command and has the necessary
7489 knowledge to parse the program's output.
7492 will have been compiled into the \*(UA binary if
7497 Shall it be necessary to define a specific connection type (rather than
7498 using a configuration file for that), the variable
7500 can be used as in, e.g.,
7501 .Ql -d server.example.com -p 783 .
7502 It is also possible to specify a per-user configuration via
7504 Note that this interface doesn't inspect the
7506 flag of a message for the command
7510 \*(UA will directly communicate with the
7516 stream socket as specified in
7518 It is possible to specify a per-user configuration via
7522 generic spam filter support via freely configurable hooks.
7523 This interface is ment for programs like
7527 and requires according behaviour in respect to the hooks' exit
7528 status for at least the command
7531 meaning a message is spam,
7535 for unsure and any other return value indicating a hard error);
7536 since the hooks can include shell code snippets diverting behaviour
7537 can be intercepted as necessary.
7539 .Va spamfilter-ham , spamfilter-noham , spamfilter-nospam , \
7542 .Va spamfilter-spam ;
7545 contains examples for some programs.
7546 The process environment of the hooks will have the variables
7547 .Ev NAIL_TMPDIR , TMPDIR
7549 .Ev NAIL_FILENAME_GENERATED
7551 Note that spam score support for
7553 isn't supported unless the \*(OPtional regular expression support is
7555 .Va spamfilter-rate-scanscore
7562 \*(OP Messages that exceed this size won't be passed through to the
7564 .Va spam-interface .
7565 The default is 420000 bytes.
7568 .It Va spamc-command
7569 \*(OP The path to the
7573 .Va spam-interface .
7574 Note that the path is not expanded, but used
7576 A fallback path will have been compiled into the \*(UA binary if the
7577 executable had been found during compilation.
7580 .It Va spamc-arguments
7581 \*(OP Even though \*(UA deals with most arguments for the
7584 automatically, it may at least sometimes be desirable to specifiy
7585 connection-related ones via this variable, e.g.,
7586 .Ql -d server.example.com -p 783 .
7590 \*(OP Specify a username for per-user configuration files for the
7592 .Va spam-interface .
7593 If this is set to the empty string then \*(UA will use the name of the
7599 \*(OP Specify the path of the
7601 domain socket on which
7603 listens for connections for the
7605 .Va spam-interface .
7606 Note that the path is not expanded, but used
7611 \*(OP Specify a username for per-user configuration files for the
7613 .Va spam-interface .
7614 If this is set to the empty string then \*(UA will use the name of the
7623 .It Va spamfilter-ham , spamfilter-noham , \
7624 spamfilter-nospam , spamfilter-rate , spamfilter-spam
7625 \*(OP Command and argument hooks for the
7627 .Va spam-interface .
7630 contains examples for some programs.
7633 .It Va spamfilter-rate-scanscore
7634 \*(OP Because of the generic nature of the
7637 spam scores are not supported for it by default, but if the \*(OPtional
7638 regular expression support is available then setting this variable can
7639 be used to overcome this restriction.
7640 It is interpreted as follows: first a number (digits) is parsed that
7641 must be followed by a semicolon
7643 and an extended regular expression.
7644 Then the latter is used to parse the first output line of the
7646 hook, and, in case the evaluation is successful, the group that has been
7647 specified via the number is interpreted as a floating point scan score.
7651 \*(OP Specifies a directory with CA certificates in PEM (Pricacy
7652 Enhanced Mail) for verification of of SSL/TLS server certificates.
7654 .Xr SSL_CTX_load_verify_locations 3
7655 for more information.
7659 \*(OP Specifies a file with CA certificates in PEM format for
7660 verification of SSL/TLS server certificates.
7662 .Xr SSL_CTX_load_verify_locations 3
7663 for more information.
7666 .It Va ssl-cert-USER@HOST , ssl-cert-HOST , ssl-cert
7667 \*(OP Variable chain that sets the file name for a SSL/TLS client
7668 certificate required by some servers.
7669 This is a direct interface to the
7673 function of the OpenSSL library, if available.
7675 .Mx Va ssl-cipher-list
7676 .It Va ssl-cipher-list-USER@HOST , ssl-cipher-list-HOST , ssl-cipher-list
7677 \*(OP Specifies a list of ciphers for SSL/TLS connections.
7678 This is a direct interface to the
7682 function of the OpenSSL library, if available; see
7684 for more information.
7685 By default \*(UA doesn't set a list of ciphers, which in effect will use a
7687 specific cipher (protocol standards ship with a list of acceptable
7688 ciphers), possibly cramped to what the actually used SSL/TLS library
7689 supports \(en the manual section
7690 .Sx "An example configuration"
7691 also contains a SSL/TLS use case.
7694 .It Va ssl-config-file
7695 \*(OP If this variable is set \*(UA will call
7696 .Xr CONF_modules_load_file 3
7697 to allow OpenSSL to be configured according to the host system wide
7699 If a non-empty value is given then this will be used to specify the
7700 configuration file to be used instead of the global OpenSSL default;
7701 note that in this case it is an error if the file cannot be loaded.
7702 The application name will always be passed as
7707 \*(OP Specifies a file that contains a CRL in PEM format to use when
7708 verifying SSL/TLS server certificates.
7712 \*(OP Specifies a directory that contains files with CRLs in PEM format
7713 to use when verifying SSL/TLS server certificates.
7716 .It Va ssl-key-USER@HOST , ssl-key-HOST , ssl-key
7717 \*(OP Variable chain that sets the file name for the private key of
7718 a SSL/TLS client certificate.
7719 If unset, the name of the certificate file is used.
7720 The file is expected to be in PEM format.
7721 This is a direct interface to the
7725 function of the OpenSSL library, if available.
7728 .It Va ssl-method-USER@HOST , ssl-method-HOST , ssl-method
7730 \*(OB Please use the newer and more flexible
7732 instead: if both values are set,
7734 will take precedence!
7735 Can be set to the following values, the actually used
7737 specification to which it is mapped is shown in parenthesis:
7739 .Pf ( Ql -ALL, TLSv1.2 ) ,
7741 .Pf ( Ql -ALL, TLSv1.1 ) ,
7743 .Pf ( Ql -ALL, TLSv1 )
7746 .Pf ( Ql -ALL, SSLv3 ) ;
7751 and thus includes the SSLv3 protocol.
7752 Note that SSLv2 is no longer supported at all.
7755 .It Va ssl-no-default-ca
7756 \*(BO\*(OP Don't load default CA locations to verify SSL/TLS server
7760 .It Va ssl-protocol-USER@HOST , ssl-protocol-HOST , ssl-protocol
7761 \*(OP Specify the used SSL/TLS protocol.
7762 This is a direct interface to the
7766 function of the OpenSSL library, if available;
7767 otherwise an \*(UA internal parser is used which understands the
7768 following subset of (case-insensitive) command strings:
7774 as well as the special value
7776 Multiple specifications may be given via a comma-separated list which
7777 ignores any whitespace.
7780 plus prefix will enable a protocol, a
7782 minus prefix will disable it, so that
7784 will enable only the TLSv1.2 protocol.
7786 It depends upon the used TLS/SSL library which protocols are actually
7787 supported and which protocols are used if
7789 is not set, but note that SSLv2 is no longer supported at all and
7791 Especially for older protocols explicitly securing
7793 may be worthwile, see
7794 .Sx "An example configuration" .
7798 \*(OP Gives the pathname to an entropy daemon socket, see
7800 Not all SSL/TLS libraries support this.
7803 .It Va ssl-rand-file
7804 \*(OP Gives the filename to a file with random entropy data, see
7805 .Xr RAND_load_file 3 .
7806 If this variable is not set, or set to the empty string, or if the
7807 filename expansion failed, then
7808 .Xr RAND_file_name 3
7809 will be used to create the filename if, and only if,
7811 documents that the SSL PRNG is not yet sufficiently seeded.
7812 If \*(UA successfully seeded the SSL PRNG then it'll update the file via
7813 .Xr RAND_write_file 3 .
7814 This variable is only used if
7816 is not set (or not supported by the SSL/TLS library).
7819 .It Va ssl-verify-USER@HOST , ssl-verify-HOST , ssl-verify
7820 \*(OP Variable chain that sets the action to be performed if an error
7821 occurs during SSL/TLS server certificate validation.
7822 Valid (case-insensitive) values are
7824 (fail and close connection immediately),
7826 (ask whether to continue on standard input),
7828 (show a warning and continue),
7830 (do not perform validation).
7836 If only set without an assigned value, then this option inhibits the
7841 header fields that include obvious references to \*(UA.
7842 There are two pitfalls associated with this:
7843 First, the message id of outgoing messages is not known anymore.
7844 Second, an expert may still use the remaining information in the header
7845 to track down the originating mail user agent.
7850 suppression doesn't occur.
7855 (\*(OP) This specifies a comma-separated list of
7860 .Sx "On terminal control and line editor" ,
7861 escape commas with backslash) to be used to overwrite or define entries.
7863 that this variable will only be queried once at program startup and can
7864 thus only be specified in resource files or on the command line.
7867 String capabilities form
7869 pairs and are expected unless noted otherwise.
7870 Numerics have to be notated as
7872 where the number is expected in normal decimal notation.
7873 Finally, booleans don't have any value but indicate a true or false
7874 state simply by being defined or not; this indeed means that \*(UA
7875 doesn't support undefining a boolean that normally exists.
7876 The following example defines that the terminal has 256 colours:
7878 .Bd -literal -offset indent
7879 set termcap="colors=256"
7883 Keycodes can easily be detected with the command
7885 by running it on an interactive terminal via
7889 command line option if available) and pressing some keys: here
7897 (actually a visualized numeric where
7899 stands for 1 etc.; in fact: the numeric value of
7901 in the US-ASCII character set bitwise XORd with
7904 .Ql $ echo $((0x41 ^ 0x40)) .
7907 and other control characters have to be notated as shell-style
7908 escape sequences, e.g.,
7918 The following terminal capabilities are or may be meaningful for the
7919 operation of the builtin line editor or \*(UA in general:
7922 .Bl -tag -compact -width yay
7924 .It Cd colors Ns \0or Cd Co
7926 numeric capability specifying the maximum number of colours.
7927 Note that \*(UA doesn't actually care about the terminal beside that,
7928 but always emits ANSI/ISO 6429 escape sequences for producing the
7929 colour and font attributes.
7932 .It Cd rmcup Ns \0or Cd te Ns \0/ Cd smcup Ns \0or Cd ti
7936 respectively: exit and enter the alternative screen
7938 effectively turning \*(UA into a fullscreen application.
7939 To disable that, set (at least) one to the empty string.
7941 .It Cd smkx Ns \0or Cd ks Ns \0/ Cd rmkx Ns \0or Cd ke
7945 respectively: enable and disable the keypad.
7946 This is always enabled if available, because it seems even keyboards
7947 without keypads generate other key codes for, e.g., cursor keys in that
7948 case, and only if enabled we see the codes that we are interested in.
7950 .It Cd ed Ns \0or Cd cd
7954 .It Cd clear Ns \0or Cd cl
7956 clear the screen and home cursor.
7957 (Will be simulated via
7962 .It Cd home Ns \0or Cd ho
7967 .It Cd el Ns \0or Cd ce
7969 clear to the end of line.
7970 (Will be simulated via
7972 plus repititions of space characters.)
7974 .It Cd hpa Ns \0or Cd ch
7975 .Cd column_address :
7976 move the cursor (to the given column parameter) in the current row.
7977 (Will be simulated via
7983 .Cd carriage_return :
7984 move to the first column in the current row.
7985 The default builtin fallback is
7988 .It Cd cub1 Ns \0or Cd le
7990 move the cursor left one space (non-destructively).
7991 The default builtin fallback is
7994 .It Cd cuf1 Ns \0or Cd nd
7996 move the cursor right one space (non-destructively).
7997 The default builtin fallback is
7999 which is used by most terminals.
8008 .It Va termcap-disable
8009 \*(OP Disable any interaction with a terminal control library.
8010 If set only some generic fallback builtins and possibly the content of
8012 describe the terminal to \*(UA.
8014 that this variable will only be queried once at program startup and can
8015 thus only be specified in resource files or on the command line.
8019 If defined, gives the number of lines of a message to be displayed
8022 normally, the first five lines are printed.
8026 The character set of the terminal \*(UA operates on,
8027 and the one and only supported character set that \*(UA can use if no
8028 character set conversion capabilities have been compiled into it,
8029 in which case it defaults to ISO-8859-1 unless it can deduce a value
8033 Refer to the section
8034 .Sx "Character sets"
8035 for the complete picture about character sets.
8038 .It Va user-HOST , user
8039 \*(IN Variable chain that sets a global fallback user name, which is
8040 used in case none has been given in the protocol and account-specific
8042 This variable defaults to the value of the first of
8046 that is set (the former being SystemV and POSIX standard, the latter BSD).
8050 \*(BO Setting this option enables upward compatibility with \*(UA
8051 version 15.0 in respect to which configuration options are available and
8052 how they are handled.
8053 This manual uses \*(IN and \*(OU to refer to the new and the old way of
8054 doing things, respectively.
8058 \*(BO Setting this option, also controllable via the command line option
8060 causes \*(UA to be more verbose, e.g., it will display obsoletion
8061 warnings and SSL/TLS certificate chains.
8062 Even though marked \*(BO this option may be set twice in order to
8063 increase the level of verbosity even more, in which case even details of
8064 the actual message delivery and protocol conversations are shown.
8067 is sufficient to disable verbosity as such.
8073 .It Va version , version-major , version-minor , version-update
8074 \*(RO \*(UA version information: the first variable contains a string
8075 containing the complete version identification \(en this is identical to
8076 the output of the command
8078 The latter three contain only digits: the major, minor and update
8082 .It Va writebackedited
8083 If this variable is set messages modified using the
8087 commands are written back to the current folder when it is quit;
8088 it is only honoured for writable folders in MBOX format, though.
8089 Note that the editor will be pointed to the raw message content in that
8090 case, i.e., neither MIME decoding nor decryption will have been
8091 performed, and proper RFC 4155
8093 quoting of newly added or edited content is also left as an excercise to
8097 .\" }}} (INTERNAL VARIABLES)
8100 .\" .Sh ENVIRONMENT {{{
8104 .Dq environment variable
8105 should be considered an indication that the following variables are
8106 either standardized as being vivid parts of process environments, or
8107 are commonly found in there.
8108 The process environment is inherited from the
8110 once \*(UA is started, and unless otherwise explicitly noted variables
8111 in there integrate into the normal handling of
8112 .Sx "INTERNAL VARIABLES" ,
8113 from \*(UA's point of view, i.e., they can be
8115 as such in resource files and need not necessarily come from the process
8116 environment and be managed via
8120 E.g., the following example, applicable to a POSIX shell, sets the
8122 environment variable for \*(UA only, and beforehand exports the
8124 in order to affect any further processing in the running shell:
8126 .Bd -literal -offset indent
8127 $ EDITOR="vim -u ${HOME}/.vimrc"
8129 $ COLUMNS=80 \*(uA -R
8132 .Bl -tag -width ".It Ev _AILR_"
8135 The user's preferred width in column positions for the terminal screen
8137 Queried and used once on program startup, actively managed for child
8138 processes in interactive mode.
8142 The name of the file to use for saving aborted messages if
8144 is set; this defaults to
8152 Pathname of the text editor to use in the
8156 .Sx "TILDE ESCAPES" .
8157 A default editor is used if this value is not defined.
8161 The user's home directory.
8162 This variable is only used when it resides in the process environment.
8165 to update the value at runtime.
8172 .It Ev LANG , LC_ALL , LC_COLLATE , LC_CTYPE , LC_MESSAGES
8176 .Sx "Character sets" .
8180 The user's preferred number of lines on a page or the vertical screen
8181 or window size in lines.
8182 Queried and used once on program startup, actively managed for child
8183 processes in interactive mode.
8187 Pathname of the directory lister to use in the
8189 command when operating on local mailboxes.
8192 (path search through
8197 Force identification as the given user, i.e., identical to the
8199 command line option.
8200 This variable is standardized and therefore used in preference to the
8203 it is only used when it resides in the process environment.
8204 \*(ID The variable can be updated at runtime via
8206 but without having an effect on \*(UA itself.
8210 Is used as the user's mailbox, if set.
8211 Otherwise, a system-dependent default is used.
8212 Supports a logical subset of the special conventions that are documented
8221 \*(OP Overrides the default path search for
8222 .Sx "The Mailcap files" ,
8223 which is defined in the standard RFC 1524 as
8224 .Ql ~/.mailcap:\:/etc/mailcap:\:/usr/etc/mailcap:\:/usr/local/etc/mailcap .
8225 .\" TODO we should have a mailcaps-default virtual RDONLY option!
8226 (\*(UA makes it a configuration option, however.)
8227 Note this is not a search path, but a path search.
8231 Is used as a startup file instead of
8234 When \*(UA scripts are invoked on behalf of other users,
8235 either this variable should be set to
8239 command line option should be used in order to avoid side-effects from
8240 reading their configuration files.
8241 This variable is only used when it resides in the process environment.
8245 The name of the user's mbox file.
8246 A logical subset of the special conventions that are documented for the
8251 The fallback default is
8256 Traditionally this secondary mailbox is used as the file to save
8257 messages from the system mailbox that have been read.
8259 .Sx "Message states" .
8262 .It Ev NAIL_NO_SYSTEM_RC
8263 If this variable is set then reading of
8265 at startup is inhibited, i.e., the same effect is achieved as if \*(UA
8266 had been started up with the option
8268 This variable is only used when it resides in the process environment.
8272 \*(IN\*(OP This variable overrides the default location of the user's
8278 Pathname of the program to use for backing the command
8282 variable enforces usage of a pager for output.
8283 The default paginator is
8285 (path search through
8288 \*(UA inspects the contents of this variable: if its contains the string
8290 then a non-existing environment variable
8297 dependent on whether terminal control support is available and whether
8298 that supports full (alternative) screen mode or not (also see
8299 .Sx "On terminal control and line editor" ) .
8303 will optionally be set to
8310 A list of directories that is searched by the shell when looking for
8311 commands (as such only recognized in the process environment).
8315 The shell to use for the commands
8321 and when starting subprocesses.
8322 A default shell is used if this option is not defined.
8326 \*(OP The terminal type for which output is to be prepared.
8327 For extended colour and font control please refer to
8328 .Sx "Coloured display" ,
8329 and for terminal management in general to
8330 .Sx "On terminal control and line editor" .
8334 Used as directory for temporary files instead of
8337 This variable is only used when it resides in the process environment.
8340 to update the value at runtime.
8344 This variable comes from the BSD world and is only used if the POSIX
8345 standard environment variable
8347 which originates in SysV
8350 Force identification as the given user, i.e., identical to the
8352 command line option.
8353 This variable is only used when it resides in the process environment.
8354 \*(ID The variable can be updated at runtime via
8356 but without having an effect on \*(UA itself.
8360 Pathname of the text editor to use in the
8364 .Sx "TILDE ESCAPES" .
8372 .Bl -tag -width ".It Pa _etc/mime.type_"
8374 File giving initial commands.
8377 System wide initialization file.
8381 \*(OP Personal MIME type handler definition file, see
8382 .Sx "The Mailcap files" .
8383 (RFC 1524 location, the actual path is a configuration option.)
8387 \*(OP System wide MIME type handler definition file, see
8388 .Sx "The Mailcap files" .
8389 (RFC 1524 location, the actual path is a configuration option.)
8392 .It Pa ~/.mime.types
8393 Personal MIME types, see
8394 .Sx "The mime.types files" .
8397 .It Pa /etc/mime.types
8398 System wide MIME types, see
8399 .Sx "The mime.types files" .
8403 \*(IN\*(OP The default location of the users
8405 file \(en the section
8406 .Sx "The .netrc file"
8407 documents the file format.
8410 .\" .Ss "The mime.types files" {{{
8411 .Ss "The mime.types files"
8413 When sending messages \*(UA tries to determine the content type of all
8415 When displaying message content or attachments \*(UA uses the content
8416 type to decide wether it can directly display data or wether it needs to
8417 deal with content handlers.
8418 It learns about MIME types and how to treat them by reading
8420 files, the loading of which can be controlled by setting the variable
8421 .Va mimetypes-load-control .
8424 can also be used to deal with MIME types.)
8426 files have the following syntax:
8429 .Dl type/subtype extension [extension ...]
8434 are strings describing the file contents, and one or multiple
8436 s, separated by whitespace, name the part of a filename starting after
8437 the last dot (of interest).
8438 Comments may be introduced anywhere on a line with a number sign
8440 causing the remaining line to be discarded.
8442 \*(UA also supports an extended, non-portable syntax in specially
8443 crafted files, which can be loaded via the alternative value syntax of
8444 .Va mimetypes-load-control
8445 and prepends an optional
8449 .Dl [type-marker ]type/subtype extension [extension ...]
8452 The following type markers are supported:
8455 .Bl -tag -compact -offset indent -width ".It Ar _n_u"
8457 Treat message parts with this content as plain text.
8462 Treat message parts with this content as HTML tagsoup.
8463 If the \*(OPal HTML-tagsoup-to-text converter is not available treat
8464 the content as plain text instead.
8468 but instead of falling back to plain text require an explicit content
8469 handler to be defined.
8474 for sending messages:
8476 .Va mime-allow-text-controls ,
8477 .Va mimetypes-load-control .
8478 For reading etc. messages:
8479 .Sx "HTML mail and MIME attachments" ,
8480 .Sx "The Mailcap files" ,
8482 .Va mime-counter-evidence ,
8483 .Va mimetypes-load-control ,
8484 .Va pipe-TYPE/SUBTYPE ,
8485 .Va pipe-EXTENSION .
8488 .\" .Ss "The Mailcap files" {{{
8489 .Ss "The Mailcap files"
8492 .Dq User Agent Configuration Mechanism
8493 which \*(UA \*(OPally supports.
8494 It defines a file format to be used to inform mail user agent programs
8495 about the locally-installed facilities for handling various data
8496 formats, i.e., about commands and how they can be used to display, edit
8497 etc. MIME part contents, as well as a default path search that includes
8498 multiple possible locations of
8502 environment variable that can be used to overwrite that (repeating here
8503 that it is not a search path, but instead a path search specification).
8504 Any existing files will be loaded in sequence, appending any content to
8505 the list of MIME type handler directives.
8509 files consist of a set of newline separated entries.
8510 Comment lines start with a number sign
8512 (in the first column!) and are ignored.
8513 Empty lines are also ignored.
8514 All other lines form individual entries that must adhere to the syntax
8516 To extend a single entry (not comment) its line can be continued on
8517 follow lines if newline characters are
8519 by preceding them with the backslash character
8521 The standard doesn't specify how leading whitespace of follow lines is
8522 to be treated, therefore \*(UA retains it.
8526 entries consist of a number of semicolon
8528 separated fields, and the backslash
8530 character can be used to escape any following character including
8531 semicolon and itself.
8532 The first two fields are mandatory and must occur in the specified
8533 order, the remaining fields are optional and may appear in any order.
8534 Leading and trailing whitespace of content is ignored (removed).
8537 The first field defines the MIME
8539 the entry is about to handle (case-insensitively, and no backslash
8540 escaping is possible in this field).
8541 If the subtype is specified as an asterisk
8543 the entry is ment to match all subtypes of the named type, e.g.,
8545 would match any audio type.
8546 The second field defines the shell command which shall be used to
8548 MIME parts of the given type; it is implicitly called the
8555 shell commands message (MIME part) data is passed via standard input
8556 unless the given shell command includes one or more instances of the
8559 in which case these instances will be replaced with a temporary filename
8560 and the data will have been stored in the file that is being pointed to.
8563 shell commands data is assumed to be generated on standard output unless
8564 the given command includes (one ore multiple)
8566 In any case any given
8568 format is replaced with a(n already) properly quoted filename.
8569 Note that when a command makes use of a temporary file via
8571 then \*(UA will remove it again, as if the
8572 .Cd x-mailx-tmpfile ,
8573 .Cd x-mailx-tmpfile-fill
8575 .Cd x-mailx-tmpfile-unlink
8576 flags had been set; see below for more.
8579 The optional fields either define a shell command or an attribute (flag)
8580 value, the latter being a single word and the former being a keyword
8581 naming the field followed by an equals sign
8583 succeeded by a shell command, and as usual for any
8585 content any whitespace surrounding the equals sign will be removed, too.
8586 Optional fields include the following:
8589 .Bl -tag -width textualnewlines
8591 A program that can be used to compose a new body or body part in the
8598 field, but is to be used when the composing program needs to specify the
8600 header field to be applied to the composed data.
8604 A program that can be used to edit a body or body part in the given
8609 A program that can be used to print a message or body part in the given
8614 Specifies a program to be run to test some condition, e.g., the machine
8615 architecture, or the window system in use, to determine whether or not
8616 this mailcap entry applies.
8617 If the test fails, a subsequent mailcap entry should be sought; also see
8618 .Cd x-mailx-test-once .
8620 .It Cd needsterminal
8621 This flag field indicates that the given shell command must be run on
8622 an interactive terminal.
8623 \*(UA will temporarily release the terminal to the given command in
8624 interactive mode, in non-interactive mode this entry will be entirely
8625 ignored; this flag implies
8626 .Cd x-mailx-noquote .
8628 .It Cd copiousoutput
8629 A flag field which indicates that the output of the
8631 command will be an extended stream of textual output that can be
8632 (re)integrated into \*(UA's normal visual display.
8633 It is mutually exclusive with
8636 .Cd x-mailx-always .
8638 .It Cd textualnewlines
8639 A flag field which indicates that this type of data is line-oriented and
8642 all newlines should be converted to canonical form (CRLF) before
8643 encoding, and will be in that form after decoding.
8647 This field gives a file name format, in which
8649 will be replaced by a random string, the joined combination of which
8650 will be used as the filename denoted by
8651 .Ev NAIL_FILENAME_TEMPORARY .
8652 One could specify that a GIF file being passed to an image viewer should
8653 have a name ending in
8656 .Ql nametemplate=%s.gif .
8657 Note that \*(UA ignores the name template unless that solely specifies
8658 a filename suffix that consists of (ASCII) alphabetic and numeric
8659 characters, the underscore and dot only.
8662 Names a file, in X11 bitmap (xbm) format, which points to an appropriate
8663 icon to be used to visually denote the presence of this kind of data.
8664 This field is not used by \*(UA.
8667 A textual description that describes this type of data.
8669 .It Cd x-mailx-always
8670 Extension flag field that denotes that the given
8672 command shall be executed even if multiple messages will be displayed
8674 Normally messages which require external viewers that produce output
8675 which doesn't integrate into \*(UA's visual display (i.e., don't have
8677 set) have to be addressed directly and individually.
8678 (To avoid cases where, e.g., a thousand PDF viewer instances are spawned
8681 .It Cd x-mailx-even-if-not-interactive
8682 An extension flag test field \(em by default handlers without
8684 are entirely ignored in non-interactive mode, but if this flag is set
8685 then their use will be considered.
8686 It is an error if this flag is set for commands that use the flag
8689 .It Cd x-mailx-noquote
8690 An extension flag field that indicates that even a
8693 command shall not be used to generate message quotes
8694 (as it would be by default).
8696 .It Cd x-mailx-async
8697 Extension flag field that denotes that the given
8699 command shall be executed asynchronously, without blocking \*(UA.
8700 Cannot be used in conjunction with
8703 .It Cd x-mailx-test-once
8704 Extension flag which denotes wether the given
8706 command shall be evaluated once only and the (boolean) result be cached.
8707 This is handy if some global unchanging condition is to be queried, like
8708 .Dq running under the X Window System .
8710 .It Cd x-mailx-tmpfile
8711 Extension flag field that requests creation of a zero-sized temporary
8712 file, the name of which is to be placed in the environment variable
8713 .Ev NAIL_FILENAME_TEMPORARY .
8714 It is an error to use this flag with commands that include a
8718 .It Cd x-mailx-tmpfile-fill
8719 Normally the MIME part content is passed to the handler via standard
8720 input; if this flag is set then the data will instead be written into
8722 .Cd x-mailx-tmpfile .
8723 In order to cause deletion of the temporary file you will have to set
8724 .Cd x-mailx-tmpfile-unlink
8726 It is an error to use this flag with commands that include a
8730 .It Cd x-mailx-tmpfile-unlink
8731 Extension flag field that requests that the temporary file shall be
8732 deleted automatically when the command loop is entered again at latest.
8733 (Don't use this for asynchronous handlers.)
8734 It is an error to use this flag with commands that include a
8736 format, or without also setting
8739 .Cd x-mailx-tmpfile-fill .
8741 .It Cd x-mailx-tmpfile-keep
8744 implies the three tmpfile related flags above, but if you want, e.g.,
8746 and deal with the temporary file yourself, you can add in this flag to
8748 .Cd x-mailx-tmpfile-unlink .
8753 The standard includes the possibility to define any number of additional
8754 entry fields, prefixed by
8756 Flag fields apply to the entire
8758 entry \(em in some unusual cases, this may not be desirable, but
8759 differentiation can be accomplished via separate entries, taking
8760 advantage of the fact that subsequent entries are searched if an earlier
8761 one does not provide enough information.
8764 command needs to specify the
8768 command shall not, the following will help out the latter (with enabled
8772 level \*(UA will show informations about handler evaluation):
8774 .Bd -literal -offset indent
8775 application/postscript; ps-to-terminal %s; needsterminal
8776 application/postscript; ps-to-terminal %s; compose=idraw %s
8780 In fields any occurrence of the format string
8782 will be replaced by the
8785 Named parameters from the
8787 field may be placed in the command execution line using
8789 followed by the parameter name and a closing
8792 The entire parameter should appear as a single command line argument,
8793 regardless of embedded spaces; thus:
8795 .Bd -literal -offset indent
8797 Content-type: multipart/mixed; boundary=42
8800 multipart/*; /usr/local/bin/showmulti \e
8801 %t %{boundary} ; composetyped = /usr/local/bin/makemulti
8803 # Executed shell command
8804 /usr/local/bin/showmulti multipart/mixed 42
8808 .\" TODO v15: Mailcap: %n,%F
8809 Note that \*(UA doesn't support handlers for multipart MIME parts as
8810 shown in this example (as of today).
8811 \*(UA doesn't support the additional formats
8815 An example file, also showing how to properly deal with the expansion of
8817 which includes any quotes that are necessary to make it a valid shell
8818 argument by itself and thus will cause undesired behaviour when placed
8819 in additional user-provided quotes:
8821 .Bd -literal -offset indent
8823 text/richtext; richtext %s; copiousoutput
8825 text/x-perl; perl -cWT %s
8829 trap "rm -f ${infile}" EXIT\e; \e
8830 trap "exit 75" INT QUIT TERM\e; \e
8832 x-mailx-async; x-mailx-tmpfile-keep
8834 application/*; echo "This is \e"%t\e" but \e
8835 is 50 \e% Greek to me" \e; < %s head -c 1024 | cat -vET; \e
8836 copiousoutput; x-mailx-noquote
8841 .Sx "HTML mail and MIME attachments" ,
8842 .Sx "The mime.types files" ,
8845 .Va mime-counter-evidence ,
8846 .Va pipe-TYPE/SUBTYPE ,
8847 .Va pipe-EXTENSION .
8850 .\" .Ss "The .netrc file" {{{
8851 .Ss "The .netrc file"
8855 file contains user credentials for machine accounts.
8856 The default location in the user's
8858 directory may be overridden by the
8860 environment variable.
8861 The file consists of space, tabulator or newline separated tokens.
8862 \*(UA implements a parser that supports a superset of the original BSD
8863 syntax, but users should nonetheless be aware of portability glitches
8864 of that file format, shall their
8866 be usable across multiple programs and platforms:
8869 .Bl -bullet -compact
8871 BSD doesn't support single, but only double quotation marks, e.g.,
8872 .Ql password="pass with spaces" .
8874 BSD (only?) supports escaping of single characters via a backslash
8875 (e.g., a space can be escaped via
8877 in- as well as outside of a quoted string.
8879 BSD doesn't require the final quotation mark of the final user input token.
8881 The original BSD (Berknet) parser also supported a format which allowed
8882 tokens to be separated with commas \(en whereas at least Hewlett-Packard
8883 still seems to support this syntax, \*(UA does not!
8885 As a non-portable extension some widely-used programs support
8886 shell-style comments: if an input line starts, after any amount of
8887 whitespace, with a number sign
8889 then the rest of the line is ignored.
8891 Whereas other programs may require that the
8893 file is accessible by only the user if it contains a
8899 \*(UA will always require these strict permissions.
8903 Of the following list of supported tokens \*(UA only uses (and caches)
8908 At runtime the command
8910 can be used to control \*(UA's
8914 .Bl -tag -width password
8915 .It Cd machine Ar name
8916 The hostname of the entries' machine, lowercase-normalized by \*(UA
8918 Any further file content, until either end-of-file or the occurrence
8923 first-class token is bound (only related) to the machine
8926 As an extension that shouldn't be the cause of any worries
8927 \*(UA supports a single wildcard prefix for
8929 .Bd -literal -offset indent
8930 machine *.example.com login USER password PASS
8931 machine pop3.example.com login USER password PASS
8932 machine smtp.example.com login USER password PASS
8938 .Ql pop3.example.com ,
8942 .Ql local.smtp.example.com .
8943 Note that in the example neither
8944 .Ql pop3.example.com
8946 .Ql smtp.example.com
8947 will be matched by the wildcard, since the exact matches take
8948 precedence (it is however faster to specify it the other way around).
8953 except that it is a fallback entry that is used shall none of the
8954 specified machines match; only one default token may be specified,
8955 and it must be the last first-class token.
8957 .It Cd login Ar name
8958 The user name on the remote machine.
8960 .It Cd password Ar string
8961 The user's password on the remote machine.
8963 .It Cd account Ar string
8964 Supply an additional account password.
8965 This is merely for FTP purposes.
8967 .It Cd macdef Ar name
8969 A macro is defined with the specified
8971 it is formed from all lines beginning with the next line and continuing
8972 until a blank line is (consecutive newline characters are) encountered.
8975 entries cannot be utilized by multiple machines, too, but must be
8976 defined following the
8978 they are intended to be used with.)
8981 exists, it is automatically run as the last step of the login process.
8982 This is merely for FTP purposes.
8989 .\" .Sh EXAMPLES {{{
8992 .\" .Ss "An example configuration" {{{
8993 .Ss "An example configuration"
8995 .Bd -literal -offset indent
8996 # This example assumes v15.0 compatibility mode
8999 # Where are the up-to-date SSL certificates?
9000 #set ssl-ca-dir=/etc/ssl/certs
9001 set ssl-ca-file=/etc/ssl/certs/ca-certificates.crt
9003 # (Since we manage up-to-date ones explicitly, don't use any,
9004 # possibly outdated, default certificates shipped with OpenSSL
9005 set ssl-no-default-ca
9007 # Don't use protocols older than TLS v1.2.
9008 # Change this only when the remote server doesn't support it:
9009 # maybe use ssl-protocol-HOST (or -USER@HOST) syntax to define
9010 # such explicit exceptions, then
9011 set ssl-protocol="-ALL,+TLSv1.2"
9013 # Explicitly define the list of ciphers, which may improve security,
9014 # especially with protocols older than TLS v1.2. See ciphers(1).
9015 # Hint: it is important to include "@STRENGTH": only with it the
9016 # final list will be sorted by algorithm strength.
9017 # This is an example: in reality it is possibly best to only use
9018 # ssl-cipher-list-HOST (or -USER@HOST), as necessary, again..
9019 set ssl-cipher-list="ALL:!aNULL:!MEDIUM:!LOW:\e
9020 !MD5:!RC4:!EXPORT:@STRENGTH"
9022 # Request strict transport security checks!
9023 set ssl-verify=strict
9025 # Essential setting: select allowed character sets
9026 set sendcharsets=utf-8,iso-8859-1
9028 # A very kind option: when replying to a message, first try to
9029 # use the same encoding that the original poster used herself!
9030 set reply-in-same-charset
9032 # When replying to or forwarding a message the comment and name
9033 # parts of email addresses are removed unless this variable is set
9036 # When sending messages, wait until the Mail-Transfer-Agent finishs.
9037 # Only like this you'll be able to see errors reported through the
9038 # exit status of the MTA (including the builtin SMTP one)!
9041 # Only use builtin MIME types, no mime.types(5) files
9042 set mimetypes-load-control
9044 # Default directory where we act in (relative to $HOME)
9046 # A leading "+" (often) means: under *folder*
9047 # *record* is used to save copies of sent messages
9048 set MBOX=+mbox.mbox record=+sent.mbox DEAD=+dead.mbox
9050 # Make "file mymbox" and "file myrec" go to..
9051 shortcut mymbox %:+mbox.mbox myrec +sent.mbox
9053 # Not really optional, e.g., for S/MIME
9054 set from="Your Name <address@exam.ple>"
9056 # It may be necessary to set hostname and/or smtp-hostname
9057 # if the "SERVER" of smtp and "domain" of from don't match.
9058 # The `urlencode' command can be used to encode USER and PASS
9059 set smtp=(smtp[s]/submission)://[USER[:PASS]@]SERVER[:PORT] \e
9060 smtp-auth=login/plain... \e
9063 # Never refuse to start into interactive mode, and more
9065 colour-pager crt= \e
9066 followup-to followup-to-honour=ask-yes \e
9067 history-file=+.\*(uAhist history-size=-1 history-gabby \e
9068 mime-counter-evidence=0xE \e
9069 prompt='?\e?[\e$ \e@]\e& ' \e
9070 reply-to-honour=ask-yes
9072 # When `t'yping messages, show only these headers
9073 # (use `T'ype for all headers and `S'how for raw message)
9074 retain date from to cc subject
9076 # Some mailing lists
9077 mlist @xyz-editor\e.xyz$ @xyzf\e.xyz$
9078 mlsubscribe ^xfans@xfans\e.xyz$
9080 # A real life example of a very huge free mail provider
9082 set from="Your Name <address@examp.ple>"
9083 # (The plain smtp:// proto is optional)
9084 set smtp=USER:PASS@smtp.gmXil.com smtp-use-starttls
9087 # Here is a pretty large one which does not allow sending mails
9088 # if there is a domain name mismatch on the SMTP protocol level,
9089 # which would bite us if the value of from does not match, e.g.,
9090 # for people who have a sXXXXeforge project and want to speak
9091 # with the mailing list under their project account (in from),
9092 # still sending the message through their normal mail provider
9094 set from="Your Name <address@exam.ple>"
9095 set smtp=smtps://USER:PASS@smtp.yaXXex.ru:465 \e
9096 hostname=yaXXex.com smtp-hostname=
9099 # Create some new commands so that, e.g., `ls /tmp' will..
9110 ghost llS !ls -aFlrS
9113 # We don't support gpg(1) directly yet. But simple --clearsign'd
9114 # message parts can be dealt with as follows:
9117 set pipe-text/plain="@*#++=@\e
9118 < \e"${NAIL_FILENAME_TEMPORARY}\e" awk \e
9119 -v TMPFILE=\e"${NAIL_FILENAME_TEMPORARY}\e" '\e
9121 /^-----BEGIN PGP SIGNED MESSAGE-----/,/^$/ {\e
9124 print \e"--- GPG --verify ---\e";\e
9125 system(\e"gpg --verify \e" TMPFILE \e" 2>&1\e");\e
9126 print \e"--- GPG --verify ---\e";\e
9130 /^-----BEGIN PGP SIGNATURE-----/,\e
9131 /^-----END PGP SIGNATURE-----/ {\e
9141 !printf 'Key IDs to gpg --recv-keys: ';\e
9143 gpg --recv-keys ${keyids};
9149 When storing passwords in
9151 appropriate permissions should be set on this file with
9152 .Ql $ chmod 0600 \*(ur .
9155 is available user credentials can be stored in the central
9157 file instead; e.g., here is a different version of the example account
9158 that sets up SMTP and POP3:
9160 .Bd -literal -offset indent
9162 set from="Your Name <address@exam.ple>"
9164 #set agent-shell-lookup="gpg -d .pass.gpg"
9166 set smtp=smtps://smtp.yXXXXx.ru:465 \e
9167 smtp-hostname= hostname=yXXXXx.com
9168 set pop3-keepalive=240 pop3-no-apop-pop.yXXXXx.ru
9169 ghost xp fi pop3s://pop.yXXXXx.ru
9178 .Bd -literal -offset indent
9179 machine *.yXXXXx.ru login USER password PASS
9184 .Va agent-shell-lookup
9185 is available things could be diversified further by using encrypted
9186 password storage: for this, don't specify
9190 file and instead uncomment the line that defines agent lookup in the
9193 above, then create the encrypted password storage file
9196 .Bd -literal -offset indent
9199 $ eval `gpg-agent --daemon \e
9200 --pinentry-program=/usr/bin/pinentry-curses \e
9201 --max-cache-ttl 99999 --default-cache-ttl 99999`
9205 This configuration should now work just fine (use the
9207 command line option for a(n almost) dry-run):
9210 .Dl $ echo text | \*(uA -vv -AXandeX -s Subject user@exam.ple
9213 .\" .Ss "Signed and encrypted messages with S/MIME" {{{
9214 .Ss "Signed and encrypted messages with S/MIME"
9216 \*(OP S/MIME provides two central mechanisms:
9217 message signing and message encryption.
9218 A signed message contains some data in addition to the regular text.
9219 The data can be used to verify that the message was sent using a valid
9220 certificate, that the sender's address in the message header matches
9221 that in the certificate, and that the message text has not been altered.
9222 Signing a message does not change its regular text;
9223 it can be read regardless of whether the recipient's software is able to
9227 It is thus usually possible to sign all outgoing messages if so desired.
9228 Encryption, in contrast, makes the message text invisible for all people
9229 except those who have access to the secret decryption key.
9230 To encrypt a message, the specific recipient's public encryption key
9232 It is therefore not possible to send encrypted mail to people unless their
9233 key has been retrieved from either previous communication or public key
9235 A message should always be signed before it is encrypted.
9236 Otherwise, it is still possible that the encrypted message text is
9240 A central concept to S/MIME is that of the certification authority (CA).
9241 A CA is a trusted institution that issues certificates.
9242 For each of these certificates it can be verified that it really
9243 originates from the CA, provided that the CA's own certificate is
9245 A set of CA certificates is usually delivered with OpenSSL and installed
9247 If you trust the source of your OpenSSL software installation,
9248 this offers reasonable security for S/MIME on the Internet.
9250 .Va ssl-no-default-ca
9254 .Va smime-ca-dir . )
9255 In general, a certificate cannot be more secure than the method its CA
9256 certificate has been retrieved with, though.
9257 Thus if you download a CA certificate from the Internet,
9258 you can only trust the messages you verify using that certificate as
9259 much as you trust the download process.
9262 The first thing you need for participating in S/MIME message exchange is
9263 your personal certificate, including a private key.
9264 The certificate contains public information, in particular your name and
9265 your email address(es), and the public key that is used by others to
9266 encrypt messages for you,
9267 and to verify signed messages they supposedly received from you.
9268 The certificate is included in each signed message you send.
9269 The private key must be kept secret.
9270 It is used to decrypt messages that were previously encrypted with your
9271 public key, and to sign messages.
9274 For personal use it is recommended that you get a S/MIME certificate
9275 from one of the major CAs on the Internet using your WWW browser.
9276 Many CAs offer such certificates for free.
9278 .Lk https://www.CAcert.org
9279 which issues client and server certificates to members of their
9280 community for free; their root certificate
9281 .Pf ( Lk https://\:www.cacert.org/\:certs/\:root.crt )
9282 is often not in the default set of trusted CA root certificates, though,
9283 which means you will have to download their root certificate separately
9284 and ensure it is part of our S/MIME certificate validation chain by
9287 or as a vivid member of the
9289 But let's take a step-by-step tour on how to setup S/MIME with
9290 a certificate from CAcert.org despite this situation!
9293 First of all you will have to become a member of the CAcert.org
9294 community, simply by registrating yourself via the web interface.
9295 Once you are, create and verify all email addresses you want to be able
9296 to create signed and encrypted messages for/with using the corresponding
9297 entries of the web interface.
9298 Now ready to create S/MIME certificates, so let's create a new
9299 .Dq client certificate ,
9300 ensure to include all email addresses that should be covered by the
9301 certificate in the following web form, and also to use your name as the
9305 Create a private key and a certificate request on your local computer
9306 (please see the manual pages of the used commands for more in-depth
9307 knowledge on what the used arguments etc. do):
9310 .Dl openssl req -nodes -newkey rsa:4096 -keyout key.pem -out creq.pem
9313 Afterwards copy-and-paste the content of
9315 into the certificate-request (CSR) field of the web form on the
9316 CAcert.org website (you may need to unfold some
9317 .Dq advanced options
9318 to see the corresponding text field).
9319 This last step will ensure that your private key (which never left your
9320 box) and the certificate belong together (through the public key that
9321 will find its way into the certificate via the certificate-request).
9322 You are now ready and can create your CAcert certified certificate.
9323 Download and store or copy-and-paste it as
9328 In order to use your new S/MIME setup you will have to create
9329 a combined private key/public key (certificate) file:
9332 .Dl cat key.pem pub.crt > ME@HERE.com.paired
9335 This is the file \*(UA will work with.
9336 If you have created your private key with a passphrase then \*(UA will
9337 ask you for it whenever a message is signed or decrypted.
9338 Set the following variables to henceforth use S/MIME (setting
9340 is of interest for verification only):
9342 .Bd -literal -offset indent
9343 set smime-ca-file=ALL-TRUSTED-ROOT-CERTS-HERE \e
9344 smime-sign-cert=ME@HERE.com.paired \e
9345 smime-sign-message-digest=SHA256 \e
9350 From each signed message you send, the recipient can fetch your
9351 certificate and use it to send encrypted mail back to you.
9352 Accordingly if somebody sends you a signed message, you can do the same,
9355 command to check the validity of the certificate.
9358 Variables of interest for S/MIME signing:
9362 .Va smime-crl-file ,
9363 .Va smime-no-default-ca ,
9365 .Va smime-sign-cert ,
9366 .Va smime-sign-include-certs
9368 .Va smime-sign-message-digest .
9371 After it has been verified save the certificate via
9373 and tell \*(UA that it should use it for encryption for further
9374 communication with that somebody:
9376 .Bd -literal -offset indent
9378 set smime-encrypt-USER@HOST=FILENAME \e
9379 smime-cipher-USER@HOST=AES256
9383 Additional variables of interest for S/MIME en- and decryption:
9386 .Va smime-encrypt-USER@HOST .
9389 You should carefully consider if you prefer to store encrypted messages
9391 If you do, anybody who has access to your mail folders can read them,
9392 but if you do not, you might be unable to read them yourself later if
9393 you happen to lose your private key.
9396 command saves messages in decrypted form, while the
9400 commands leave them encrypted.
9403 Note that neither S/MIME signing nor encryption applies to message
9404 subjects or other header fields yet.
9405 Thus they may not contain sensitive information for encrypted messages,
9406 and cannot be trusted even if the message content has been verified.
9407 When sending signed messages,
9408 it is recommended to repeat any important header information in the
9412 .\" .Ss "Using CRLs with S/MIME or SSL/TLS" {{{
9413 .Ss "Using CRLs with S/MIME or SSL/TLS"
9415 \*(OP Certification authorities (CAs) issue certificate revocation
9416 lists (CRLs) on a regular basis.
9417 These lists contain the serial numbers of certificates that have been
9418 declared invalid after they have been issued.
9419 Such usually happens because the private key for the certificate has
9421 because the owner of the certificate has left the organization that is
9422 mentioned in the certificate, etc.
9423 To seriously use S/MIME or SSL/TLS verification,
9424 an up-to-date CRL is required for each trusted CA.
9425 There is otherwise no method to distinguish between valid and
9426 invalidated certificates.
9427 \*(UA currently offers no mechanism to fetch CRLs, nor to access them on
9428 the Internet, so you have to retrieve them by some external mechanism.
9431 \*(UA accepts CRLs in PEM format only;
9432 CRLs in DER format must be converted, like, e.\|g.:
9435 .Dl $ openssl crl \-inform DER \-in crl.der \-out crl.pem
9438 To tell \*(UA about the CRLs, a directory that contains all CRL files
9439 (and no other files) must be created.
9444 variables, respectively, must then be set to point to that directory.
9445 After that, \*(UA requires a CRL to be present for each CA that is used
9446 to verify a certificate.
9449 .\" .Ss "Handling spam" {{{
9452 \*(OP \*(UA can make use of several spam interfaces for the purpose of
9453 identification of, and, in general, dealing with spam messages.
9454 A precondition of most commands in order to function is that the
9456 variable is set to one of the supported interfaces.
9457 Once messages have been identified as spam their (volatile)
9459 state can be prompted: the
9463 message specifications will address respective messages and their
9465 entries will be used when displaying the
9467 in the header display.
9472 rates the given messages and sets their
9475 If the spam interface offers spam scores those can also be displayed in
9476 the header display by including the
9486 will interact with the Bayesian filter of the chosen interface and learn
9487 the given messages as
9491 respectively; the last command can be used to cause
9493 of messages; it adheres to their current
9495 state and thus reverts previous teachings.
9500 will simply set and clear, respectively, the mentioned volatile
9502 message flag, without any interface interaction.
9509 .Va spam-interface Ns s
9513 require a running instance of the
9515 server in order to function, started with the option
9517 shall Bayesian filter learning be possible.
9519 only works via a local path-based
9521 socket, but otherwise the following will be equivalently fine:
9523 .Bd -literal -offset indent
9524 $ spamd -i localhost:2142 -i /tmp/.spamsock -d [-L] [-l]
9525 $ spamd --listen=localhost:2142 --listen=/tmp/.spamsock \e
9526 --daemonize [--local] [--allow-tell]
9530 Thereafter \*(UA can make use of these interfaces:
9532 .Bd -literal -offset indent
9533 $ \*(uA -Sspam-interface=spamd -Sspam-maxsize=500000 \e
9534 -Sspamd-socket=/tmp/.spamsock -Sspamd-user=
9536 $ \*(uA -Sspam-interface=spamc -Sspam-maxsize=500000 \e
9537 -Sspamc-command=/usr/local/bin/spamc \e
9538 -Sspamc-arguments="-U /tmp/.spamsock" -Sspamc-user=
9540 $ \*(uA -Sspam-interface=spamc -Sspam-maxsize=500000 \e
9541 -Sspamc-command=/usr/local/bin/spamc \e
9542 -Sspamc-arguments="-d localhost -p 2142" -Sspamc-user=
9546 Using the generic filter approach allows usage of programs like
9550 Here is an example for the former, requiring it to be accessible via
9553 .Bd -literal -offset indent
9554 $ \*(uA -Sspam-interface=filter -Sspam-maxsize=500000 \e
9555 -Sspamfilter-ham="bogofilter -n" \e
9556 -Sspamfilter-noham="bogofilter -N" \e
9557 -Sspamfilter-nospam="bogofilter -S" \e
9558 -Sspamfilter-rate="bogofilter -TTu 2>/dev/null" \e
9559 -Sspamfilter-spam="bogofilter -s" \e
9560 -Sspamfilter-rate-scanscore="1;^(.+)$"
9564 Because messages must exist on local storage in order to be scored (or
9565 used for Bayesian filter training), it is possibly a good idea to
9566 perform the local spam check last:
9568 .Bd -literal -offset indent
9569 define spamdelhook {
9571 spamset (header x-dcc-brand-metrics "bulk")
9572 # Server-side spamassassin(1)
9573 spamset (header x-spam-flag "YES")
9574 del :s # TODO we HAVE to be able to do `spamrate :u ! :sS'
9580 set folder-hook-FOLDER=spamdelhook
9584 See also the documentation for the variables
9585 .Va spam-interface , spam-maxsize ,
9586 .Va spamc-command , spamc-arguments , spamc-user ,
9587 .Va spamd-socket , spamd-user ,
9588 .Va spamfilter-ham , spamfilter-noham , spamfilter-nospam , \
9591 .Va spamfilter-rate-scanscore .
9599 .\" .Ss "\*(UA shortly hangs on startup" {{{
9600 .Ss "\*(UA shortly hangs on startup"
9602 This can have two reasons, one is the necessity to wait for a file lock
9603 and can't be helped, the other being that \*(UA calls the function
9605 in order to query the nodename of the box (sometimes the real one is
9606 needed instead of the one represented by the internal variable
9608 You may have varying success by ensuring that the real hostname and
9612 or, more generally, that the name service is properly setup \(en
9615 return what you'd expect?
9616 Does this local hostname has a domain suffix?
9617 RFC 6762 standardized the link-local top-level domain
9621 .\" .Ss "I can't login to Google mail a.k.a. GMail" {{{
9622 .Ss "I can't login to Google mail a.k.a. GMail"
9624 Since 2014 some free service providers classify programs as
9626 unless they use a special authentification method (OAuth 2.0) which
9627 wasn't standardized for non-HTTP protocol authentication token query
9628 until August 2015 (RFC 7628).
9631 Different to Kerberos / GSSAPI, which is developed since the mid of the
9632 1980s, where a user can easily create a local authentication ticket for
9633 her- and himself with the locally installed
9635 program, that protocol has no such local part but instead requires
9636 a world-wide-web query to create or fetch a token; since there is no
9637 local cache this query has to be performed whenever \*(UA is invoked
9638 from the command line (in interactive sessions situation may differ).
9641 \*(UA doesn't support OAuth.
9642 Because of this it is necessary to declare \*(UA a
9644 (on the providers account web page) in order to read and send mail.
9645 However, it also seems possible to take the following steps instead:
9650 give the provider the number of a mobile phone,
9653 .Dq 2-Step Verification ,
9655 create an application specific password (16 characters), and
9657 use that special password instead of your real Google account password in
9658 S-nail (for more on that see the section
9659 .Sx "On URL syntax and credential lookup" ) .
9665 .\" .Sh "SEE ALSO" {{{
9683 .Xr spamassassin 1 ,
9709 M. Douglas McIlroy writes in his article
9710 .Dq A Research UNIX Reader: Annotated Excerpts \
9711 from the Programmer's Manual, 1971-1986
9714 command already appeared in First Edition
9718 .Bd -ragged -offset indent
9719 Electronic mail was there from the start.
9720 Never satisfied with its exact behavior, everybody touched it at one
9721 time or another: to assure the safety of simultaneous access, to improve
9722 privacy, to survive crashes, to exploit uucp, to screen out foreign
9723 freeloaders, or whatever.
9724 Not until v7 did the interface change (Thompson).
9725 Later, as mail became global in its reach, Dave Presotto took charge and
9726 brought order to communications with a grab-bag of external networks
9732 Mail was written in 1978 by Kurt Shoens and developed as part of the
9735 distribution until 1995.
9736 Mail has then seen further development in open source
9738 variants, noticeably by Christos Zoulas in
9740 Basing upon this Nail, later Heirloom Mailx, was developed by Gunnar
9741 Ritter in the years 2000 until 2008.
9742 Since 2012 S-nail is maintained by Steffen (Daode) Nurpmeso.
9743 This man page is derived from
9744 .Dq The Mail Reference Manual
9745 that was originally written by Kurt Shoens.
9752 .An "Christos Zoulas" ,
9753 .An "Gunnar Ritter" ,
9754 .An "Steffen Nurpmeso" Aq Mt s-nail-users@lists.sourceforge.net
9756 .Mt s-mailx@sdaoden.eu ) .
9762 The character set conversion uses and relies upon the
9765 Its functionality differs widely between the various system environments
9769 Limitations with POP3 mailboxes are:
9770 It is not possible to edit messages, they can only be copied and deleted.
9771 The line count for the header display is only appropriate if the entire
9772 message has been downloaded from the server.
9773 The status field of a message is maintained by the server between
9774 connections; some servers do not update it at all, and with a server
9777 command will not cause the message status to be reset.
9782 variable have no effect.
9783 It is not possible to rename or to remove POP3 mailboxes.
9790 is typed while a POP3 operation is in progress, \*(UA will wait
9791 until the operation can be safely aborted, and will then return to the
9792 command loop and print the prompt again.
9795 is typed while \*(UA is waiting for the operation to complete, the
9796 operation itself will be cancelled.
9797 In this case, data that has not been fetched yet will have to be fetched
9798 before the next command can be performed.
9799 If the cancelled operation was using an SSL/TLS encrypted channel,
9800 an error in the SSL transport will very likely result and render the
9801 connection unusable.
9804 As \*(UA is a mail user agent, it provides only basic SMTP services.
9805 If it fails to contact its upstream SMTP server, it will not make
9806 further attempts to transfer the message at a later time,
9807 and it does not leave other information about this condition than an
9808 error message on the terminal and an entry in
9810 This is usually not a problem if the SMTP server is located in the same
9811 local network as the computer on which \*(UA is run.
9812 However, care should be taken when using a remote server of an ISP;
9813 it might be better to set up a local SMTP server then which just acts as
9817 \*(UA immediately contacts the SMTP server (or
9819 It would not make much sense for \*(UA to defer outgoing mail since SMTP
9820 servers usually provide much more elaborated delay handling than \*(UA
9821 could perform as a client.
9829 from the distribution or the repository.
9831 After deleting some message of a POP3 mailbox the header summary falsely
9832 claims that there are no messages to display, you need to perform
9833 a scroll or dot movement to restore proper state.
9835 In threaded display a power user may encounter crashes very
9836 occasionally (this is may and very).