1MAILX(1P) POSIX Programmer's Manual MAILX(1P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
13 mailx — process messages
14
16 Send Mode
17 mailx [−s subject] address...
18 Receive Mode
20 mailx −e
21 mailx [−HiNn] [−F] [−u user]
23 mailx −f [−HiNn] [−F] [file]
25
27 The mailx utility provides a message sending and receiving facility. It
28 has two major modes, selected by the options used: Send Mode and
29 Receive Mode.
30 On systems that do not support the User Portability Utilities option,
32 an application using mailx shall have the ability to send messages in
33 an unspecified manner (Send Mode). Unless the first character of one or
34 more lines is <tilde> ('~'), all characters in the input message shall
35 appear in the delivered message, but additional characters may be
36 inserted in the message before it is retrieved.
37 On systems supporting the User Portability Utilities option, mail-
39 receiving capabilities and other interactive features, Receive Mode,
40 described below, also shall be enabled.
41 Send Mode
43 Send Mode can be used by applications or users to send messages from
44 the text in standard input.
45 Receive Mode
47 Receive Mode is more oriented towards interactive users. Mail can be
48 read and sent in this interactive mode.
49 When reading mail, mailx provides commands to facilitate saving, delet‐
51 ing, and responding to messages. When sending mail, mailx allows edit‐
52 ing, reviewing, and other modification of the message as it is entered.
53 Incoming mail shall be stored in one or more unspecified locations for
55 each user, collectively called the system mailbox for that user. When
56 mailx is invoked in Receive Mode, the system mailbox shall be the
57 default place to find new mail. As messages are read, they shall be
58 marked to be moved to a secondary file for storage, unless specific
59 action is taken. This secondary file is called the mbox and is normally
60 located in the directory referred to by the HOME environment variable
61 (see MBOX in the ENVIRONMENT VARIABLES section for a description of
62 this file). Messages shall remain in this file until explicitly
63 removed. When the −f option is used to read mail messages from sec‐
64 ondary files, messages shall be retained in those files unless specifi‐
65 cally removed. All three of these locations—system mailbox, mbox, and
66 secondary file—are referred to in this section as simply ``mailboxes'',
67 unless more specific identification is required.
68
70 The mailx utility shall conform to the Base Definitions volume of
71 POSIX.1‐2008, Section 12.2, Utility Syntax Guidelines.
72 The following options shall be supported. (Only the −s subject option
74 shall be required on all systems. The other options are required only
75 on systems supporting the User Portability Utilities option.)
76 −e Test for the presence of mail in the system mailbox. The
78 mailx utility shall write nothing and exit with a successful
79 return code if there is mail to read.
80 −f Read messages from the file named by the file operand instead
82 of the system mailbox. (See also folder.) If no file operand
83 is specified, read messages from mbox instead of the system
84 mailbox.
85 −F Record the message in a file named after the first recipient.
87 The name is the login-name portion of the address found first
88 on the To: line in the mail header. Overrides the record
89 variable, if set (see Internal Variables in mailx).
90 −H Write a header summary only.
92 −i Ignore interrupts. (See also ignore.)
94 −n Do not initialize from the system default start-up file. See
96 the EXTENDED DESCRIPTION section.
97 −N Do not write an initial header summary.
99 −s subject
101 Set the Subject header field to subject. All characters in
102 the subject string shall appear in the delivered message. The
103 results are unspecified if subject is longer than {LINE_MAX}
104 − 10 bytes or contains a <newline>.
105 −u user Read the system mailbox of the login name user. This shall
107 only be successful if the invoking user has appropriate priv‐
108 ileges to read the system mailbox of that user.
109
111 The following operands shall be supported:
112 address Addressee of message. When −n is specified and no user start-
114 up files are accessed (see the EXTENDED DESCRIPTION section),
115 the user or application shall ensure this is an address to
116 pass to the mail delivery system. Any system or user start-up
117 files may enable aliases (see alias under Commands in mailx)
118 that may modify the form of address before it is passed to
119 the mail delivery system.
120 file A pathname of a file to be read instead of the system mailbox
122 when −f is specified. The meaning of the file option-argument
123 shall be affected by the contents of the folder internal
124 variable; see Internal Variables in mailx.
125
127 When mailx is invoked in Send Mode (the first synopsis line), standard
128 input shall be the message to be delivered to the specified addresses.
129 When in Receive Mode, user commands shall be accepted from stdin. If
130 the User Portability Utilities option is not supported, standard input
131 lines beginning with a <tilde> ('~') character produce unspecified
132 results.
133 If the User Portability Utilities option is supported, then in both
135 Send and Receive Modes, standard input lines beginning with the escape
136 character (usually <tilde> ('~')) shall affect processing as described
137 in Command Escapes in mailx.
138
140 When mailx is used as described by this volume of POSIX.1‐2008, the
141 file option-argument (see the −f option) and the mbox shall be text
142 files containing mail messages, formatted as described in the OUTPUT
143 FILES section. The nature of the system mailbox is unspecified; it need
144 not be a file.
145
147 Some of the functionality described in this section shall be provided
148 on implementations that support the User Portability Utilities option
149 as described in the text, and is not further shaded for this option.
150 The following environment variables shall affect the execution of
152 mailx:
153 DEAD Determine the pathname of the file in which to save partial
155 messages in case of interrupts or delivery errors. The
156 default shall be dead.letter in the directory named by the
157 HOME variable. The behavior of mailx in saving partial mes‐
158 sages is unspecified if the User Portability Utilities option
159 is not supported and DEAD is not defined with the value
160 /dev/null.
161 EDITOR Determine the name of a utility to invoke when the edit (see
163 Commands in mailx) or ~e (see Command Escapes in mailx) com‐
164 mand is used. The default editor is unspecified. On XSI-con‐
165 formant systems it is ed. The effects of this variable are
166 unspecified if the User Portability Utilities option is not
167 supported.
168 HOME Determine the pathname of the user's home directory.
170 LANG Provide a default value for the internationalization vari‐
172 ables that are unset or null. (See the Base Definitions vol‐
173 ume of POSIX.1‐2008, Section 8.2, Internationalization Vari‐
174 ables for the precedence of internationalization variables
175 used to determine the values of locale categories.)
176 LC_ALL If set to a non-empty string value, override the values of
178 all the other internationalization variables.
179 LC_CTYPE Determine the locale for the interpretation of sequences of
181 bytes of text data as characters (for example, single-byte as
182 opposed to multi-byte characters in arguments and input
183 files) and the handling of case-insensitive address and
184 header-field comparisons.
185 LC_TIME This variable may determine the format and contents of the
187 date and time strings written by mailx. This volume of
188 POSIX.1‐2008 specifies the effects of this variable only for
189 systems supporting the User Portability Utilities option.
190 LC_MESSAGES
192 Determine the locale that should be used to affect the format
193 and contents of diagnostic messages written to standard error
194 and informative messages written to standard output.
195 LISTER Determine a string representing the command for writing the
197 contents of the folder directory to standard output when the
198 folders command is given (see folders in Commands in mailx).
199 Any string acceptable as a command_string operand to the sh
200 −c command shall be valid. If this variable is null or not
201 set, the output command shall be ls. The effects of this
202 variable are unspecified if the User Portability Utilities
203 option is not supported.
204 MAILRC Determine the pathname of the start-up file. The default
206 shall be .mailrc in the directory referred to by the HOME
207 environment variable. The behavior of mailx is unspecified if
208 the User Portability Utilities option is not supported and
209 MAILRC is not defined with the value /dev/null.
210 MBOX Determine a pathname of the file to save messages from the
212 system mailbox that have been read. The exit command shall
213 override this function, as shall saving the message explic‐
214 itly in another file. The default shall be mbox in the direc‐
215 tory named by the HOME variable. The effects of this variable
216 are unspecified if the User Portability Utilities option is
217 not supported.
218 NLSPATH Determine the location of message catalogs for the processing
220 of LC_MESSAGES.
221 PAGER Determine a string representing an output filtering or pagi‐
223 nation command for writing the output to the terminal. Any
224 string acceptable as a command_string operand to the sh −c
225 command shall be valid. When standard output is a terminal
226 device, the message output shall be piped through the command
227 if the mailx internal variable crt is set to a value less the
228 number of lines in the message; see Internal Variables in
229 mailx. If the PAGER variable is null or not set, the pagina‐
230 tor shall be either more or another paginator utility docu‐
231 mented in the system documentation. The effects of this
232 variable are unspecified if the User Portability Utilities
233 option is not supported.
234 SHELL Determine the name of a preferred command interpreter. The
236 default shall be sh. The effects of this variable are
237 unspecified if the User Portability Utilities option is not
238 supported.
239 TERM If the internal variable screen is not specified, determine
241 the name of the terminal type to indicate in an unspecified
242 manner the number of lines in a screenful of headers. If
243 TERM is not set or is set to null, an unspecified default
244 terminal type shall be used and the value of a screenful is
245 unspecified. The effects of this variable are unspecified if
246 the User Portability Utilities option is not supported.
247 TZ This variable may determine the timezone used to calculate
249 date and time strings written by mailx. If TZ is unset or
250 null, an unspecified default timezone shall be used.
251 VISUAL Determine a pathname of a utility to invoke when the visual
253 command (see Commands in mailx) or ~v command-escape (see
254 Command Escapes in mailx) is used. If this variable is null
255 or not set, the full-screen editor shall be vi. The effects
256 of this variable are unspecified if the User Portability
257 Utilities option is not supported.
258
260 When mailx is in Send Mode and standard input is not a terminal, it
261 shall take the standard action for all signals.
262 In Receive Mode, or in Send Mode when standard input is a terminal, if
264 a SIGINT signal is received:
265 1. If in command mode, the current command, if there is one, shall be
267 aborted, and a command-mode prompt shall be written.
268 2. If in input mode:
270 a. If ignore is set, mailx shall write "@\n", discard the current
272 input line, and continue processing, bypassing the message-
273 abort mechanism described in item 2b.
274 b. If the interrupt was received while sending mail, either when
276 in Receive Mode or in Send Mode, a message shall be written,
277 and another subsequent interrupt, with no other intervening
278 characters typed, shall be required to abort the mail message.
279 If in Receive Mode and another interrupt is received, a com‐
280 mand-mode prompt shall be written. If in Send Mode and another
281 interrupt is received, mailx shall terminate with a non-zero
282 status.
283 In both cases listed in item b, if the message is not empty:
285 i. If save is enabled and the file named by DEAD can be cre‐
287 ated, the message shall be written to the file named by
288 DEAD. If the file exists, the message shall be written to
289 replace the contents of the file.
290 ii. If save is not enabled, or the file named by DEAD cannot
292 be created, the message shall not be saved.
293 The mailx utility shall take the standard action for all other signals.
295
297 In command and input modes, all output, including prompts and messages,
298 shall be written to standard output.
299
301 The standard error shall be used only for diagnostic messages.
302
304 Various mailx commands and command escapes can create or add to files,
305 including the mbox, the dead-letter file, and secondary mailboxes. When
306 mailx is used as described in this volume of POSIX.1‐2008, these files
307 shall be text files, formatted as follows:
308 line beginning with From<space>
310 [one or more header-lines; see Commands in mailx]
311 empty line
312 [zero or more body lines
313 empty line]
314 [line beginning with From<space>...]
315 where each message begins with the From <space> line shown, preceded by
317 the beginning of the file or an empty line. (The From <space> line is
318 considered to be part of the message header, but not one of the header-
319 lines referred to in Commands in mailx; thus, it shall not be affected
320 by the discard, ignore, or retain commands.) The formats of the remain‐
321 der of the From <space> line and any additional header lines are
322 unspecified, except that none shall be empty. The format of a message
323 body line is also unspecified, except that no line following an empty
324 line shall start with From <space>; mailx shall modify any such user-
325 entered message body lines (following an empty line and beginning with
326 From <space>) by adding one or more characters to precede the 'F'; it
327 may add these characters to From <space> lines that are not preceded by
328 an empty line.
329 When a message from the system mailbox or entered by the user is not a
331 text file, it is implementation-defined how such a message is stored in
332 files written by mailx.
333
335 The functionality in the entire EXTENDED DESCRIPTION section shall be
336 provided on implementations supporting the User Portability Utilities
337 option. The functionality described in this section shall be provided
338 on implementations that support the User Portability Utilities option
339 (and the rest of this section is not further shaded for this option).
340 The mailx utility need not support for all character encodings in all
342 circumstances. For example, inter-system mail may be restricted to
343 7-bit data by the underlying network, 8-bit data need not be portable
344 to non-internationalized systems, and so on. Under these circumstances,
345 it is recommended that only characters defined in the ISO/IEC 646:1991
346 standard International Reference Version (equivalent to ASCII) 7-bit
347 range of characters be used.
348 When mailx is invoked using one of the Receive Mode synopsis forms, it
350 shall write a page of header-summary lines (if −N was not specified and
351 there are messages, see below), followed by a prompt indicating that
352 mailx can accept regular commands (see Commands in mailx); this is
353 termed command mode. The page of header-summary lines shall contain
354 the first new message if there are new messages, or the first unread
355 message if there are unread messages, or the first message. When mailx
356 is invoked using the Send Mode synopsis and standard input is a termi‐
357 nal, if no subject is specified on the command line and the asksub
358 variable is set, a prompt for the subject shall be written. At this
359 point, mailx shall be in input mode. This input mode shall also be
360 entered when using one of the Receive Mode synopsis forms and a reply
361 or new message is composed using the reply, Reply, followup, Followup,
362 or mail commands and standard input is a terminal. When the message is
363 typed and the end of the message is encountered, the message shall be
364 passed to the mail delivery software. Commands can be entered by begin‐
365 ning a line with the escape character (by default, <tilde> ('~')) fol‐
366 lowed by a single command letter and optional arguments. See Commands
367 in mailx for a summary of these commands. It is unspecified what effect
368 these commands will have if standard input is not a terminal when a
369 message is entered using either the Send Mode synopsis, or the Read
370 Mode commands reply, Reply, followup, Followup, or mail.
371 Note: For notational convenience, this section uses the default
373 escape character, <tilde>, in all references and examples.
374 At any time, the behavior of mailx shall be governed by a set of envi‐
376 ronmental and internal variables. These are flags and valued parame‐
377 ters that can be set and cleared via the mailx set and unset commands.
378 Regular commands are of the form:
380 [command] [msglist] [argument ...]
382 If no command is specified in command mode, next shall be assumed. In
384 input mode, commands shall be recognized by the escape character, and
385 lines not treated as commands shall be taken as input for the message.
386 In command mode, each message shall be assigned a sequential number,
388 starting with 1.
389 All messages have a state that shall affect how they are displayed in
391 the header summary and how they are retained or deleted upon termina‐
392 tion of mailx. There is at any time the notion of a current message,
393 which shall be marked by a '>' at the beginning of a line in the header
394 summary. When mailx is invoked using one of the Receive Mode synopsis
395 forms, the current message shall be the first new message, if there is
396 a new message, or the first unread message if there is an unread mes‐
397 sage, or the first message if there are any messages, or unspecified if
398 there are no messages in the mailbox. Each command that takes an
399 optional list of messages (msglist) or an optional single message (mes‐
400 sage) on which to operate shall leave the current message set to the
401 highest-numbered message of the messages specified, unless the command
402 deletes messages, in which case the current message shall be set to the
403 first undeleted message (that is, a message not in the deleted state)
404 after the highest-numbered message deleted by the command, if one
405 exists, or the first undeleted message before the highest-numbered mes‐
406 sage deleted by the command, if one exists, or to an unspecified value
407 if there are no remaining undeleted messages. All messages shall be in
408 one of the following states:
409 new The message is present in the system mailbox and has not been
411 viewed by the user or moved to any other state. Messages in
412 state new when mailx quits shall be retained in the system
413 mailbox.
414 unread The message has been present in the system mailbox for more
416 than one invocation of mailx and has not been viewed by the
417 user or moved to any other state. Messages in state unread
418 when mailx quits shall be retained in the system mailbox.
419 read The message has been processed by one of the following com‐
421 mands: ~f, ~m, ~F, ~M, copy, mbox, next, pipe, print, Print,
422 top, type, Type, undelete. The delete, dp, and dt commands
423 may also cause the next message to be marked as read, depend‐
424 ing on the value of the autoprint variable. Messages that are
425 in the system mailbox and in state read when mailx quits
426 shall be saved in the mbox, unless the internal variable hold
427 was set. Messages that are in the mbox or in a secondary
428 mailbox and in state read when mailx quits shall be retained
429 in their current location.
430 deleted The message has been processed by one of the following com‐
432 mands: delete, dp, dt. Messages in state deleted when mailx
433 quits shall be deleted. Deleted messages shall be ignored
434 until mailx quits or changes mailboxes or they are specified
435 to the undelete command; for example, the message specifica‐
436 tion /string shall only search the subject lines of messages
437 that have not yet been deleted, unless the command operating
438 on the list of messages is undelete. No deleted message or
439 deleted message header shall be displayed by any mailx com‐
440 mand other than undelete.
441 preserved The message has been processed by a preserve command. When
443 mailx quits, the message shall be retained in its current
444 location.
445 saved The message has been processed by one of the following com‐
447 mands: save or write. If the current mailbox is the system
448 mailbox, and the internal variable keepsave is set, messages
449 in the state saved shall be saved to the file designated by
450 the MBOX variable (see the ENVIRONMENT VARIABLES section). If
451 the current mailbox is the system mailbox, messages in the
452 state saved shall be deleted from the current mailbox, when
453 the quit or file command is used to exit the current mailbox.
454 The header-summary line for each message shall indicate the state of
456 the message.
457 Many commands take an optional list of messages (msglist) on which to
459 operate, which defaults to the current message. A msglist is a list of
460 message specifications separated by <blank> characters, which can
461 include:
462 n Message number n.
464 + The next undeleted message, or the next deleted message for the
466 undelete command.
467 − The next previous undeleted message, or the next previous
469 deleted message for the undelete command.
470 . The current message.
472 ^ The first undeleted message, or the first deleted message for
474 the undelete command.
475 $ The last message.
477 * All messages.
479 n‐m An inclusive range of message numbers.
481 address All messages from address; any address as shown in a header
483 summary shall be matchable in this form.
484 /string All messages with string in the subject line (case ignored).
486 :c All messages of type c, where c shall be one of:
488 d Deleted messages.
490 n New messages.
492 o Old messages (any not in state read or new).
494 r Read messages.
496 u Unread messages.
498 Other commands take an optional message (message) on which to operate,
500 which defaults to the current message. All of the forms allowed for
501 msglist are also allowed for message, but if more than one message is
502 specified, only the first shall be operated on.
503 Other arguments are usually arbitrary strings whose usage depends on
505 the command involved.
506 Start-Up in mailx
508 At start-up time, mailx shall take the following steps in sequence:
509 1. Establish all variables at their stated default values.
511 2. Process command line options, overriding corresponding default val‐
513 ues.
514 3. Import any of the DEAD, EDITOR, MBOX, LISTER, PAGER, SHELL, or VIS‐
516 UAL variables that are present in the environment, overriding the
517 corresponding default values.
518 4. Read mailx commands from an unspecified system start-up file,
520 unless the −n option is given, to initialize any internal mailx
521 variables and aliases.
522 5. Process the start-up file of mailx commands named in the user
524 MAILRC variable.
525 Most regular mailx commands are valid inside start-up files, the most
527 common use being to set up initial display options and alias lists. The
528 following commands shall be invalid in the start-up file: !, edit,
529 hold, mail, preserve, reply, Reply, shell, visual, Copy, followup, and
530 Followup. Any errors in the start-up file shall either cause mailx to
531 terminate with a diagnostic message and a non-zero status or to con‐
532 tinue after writing a diagnostic message, ignoring the remainder of the
533 lines in the start-up file.
534 A blank line in a start-up file shall be ignored.
536 Internal Variables in mailx
538 The following variables are internal mailx variables. Each internal
539 variable can be set via the mailx set command at any time. The unset
540 and set no name commands can be used to erase variables.
541 In the following list, variables shown as:
543 variable
545 represent Boolean values. Variables shown as:
547 variable=value
549 shall be assigned string or numeric values. For string values, the
551 rules in Commands in mailx concerning filenames and quoting shall also
552 apply.
553 The defaults specified here may be changed by the unspecified system
555 start-up file unless the user specifies the −n option.
556 allnet All network names whose login name components match shall be
558 treated as identical. This shall cause the msglist message
559 specifications to behave similarly. The default shall be
560 noallnet. See also the alternates command and the metoo
561 variable.
562 append Append messages to the end of the mbox file upon termination
564 instead of placing them at the beginning. The default shall
565 be noappend. This variable shall not affect the save command
566 when saving to mbox.
567 ask, asksub
569 Prompt for a subject line on outgoing mail if one is not
570 specified on the command line with the −s option. The ask and
571 asksub forms are synonyms; the system shall refer to asksub
572 and noasksub in its messages, but shall accept ask and noask
573 as user input to mean asksub and noasksub. It shall not be
574 possible to set both ask and noasksub, or noask and asksub.
575 The default shall be asksub, but no prompting shall be done
576 if standard input is not a terminal.
577 askbcc Prompt for the blind copy list. The default shall be
579 noaskbcc.
580 askcc Prompt for the copy list. The default shall be noaskcc.
582 autoprint Enable automatic writing of messages after delete and
584 undelete commands. The default shall be noautoprint.
585 bang Enable the special-case treatment of <exclamation-mark> char‐
587 acters ('!') in escape command lines; see the escape command
588 and Command Escapes in mailx. The default shall be nobang,
589 disabling the expansion of '!' in the command argument to
590 the ~! command and the ~<!command escape.
591 cmd=command
593 Set the default command to be invoked by the pipe command.
594 The default shall be nocmd.
595 crt=number
597 Pipe messages having more than number lines through the com‐
598 mand specified by the value of the PAGER variable. The
599 default shall be nocrt. If it is set to null, the value used
600 is implementation-defined.
601 debug Enable verbose diagnostics for debugging. Messages are not
603 delivered. The default shall be nodebug.
604 dot When dot is set, a <period> on a line by itself during mes‐
606 sage input from a terminal shall also signify end-of-file (in
607 addition to normal end-of-file). The default shall be nodot.
608 If ignoreeof is set (see below), a setting of nodot shall be
609 ignored and the <period> is the only method to terminate
610 input mode.
611 escape=c Set the command escape character to be the character 'c'. By
613 default, the command escape character shall be <tilde>. If
614 escape is unset, <tilde> shall be used; if it is set to null,
615 command escaping shall be disabled.
616 flipr Reverse the meanings of the R and r commands. The default
618 shall be noflipr.
619 folder=directory
621 The default directory for saving mail files. User-specified
622 filenames beginning with a <plus-sign> ('+') shall be
623 expanded by preceding the filename with this directory name
624 to obtain the real pathname. If directory does not start with
625 a <slash> ('/'), the contents of HOME shall be prefixed to
626 it. The default shall be nofolder. If folder is unset or set
627 to null, user-specified filenames beginning with '+' shall
628 refer to files in the current directory that begin with the
629 literal '+' character. See also outfolder below. The folder
630 value need not affect the processing of the files named in
631 MBOX and DEAD.
632 header Enable writing of the header summary when entering mailx in
634 Receive Mode. The default shall be header.
635 hold Preserve all messages that are read in the system mailbox
637 instead of putting them in the mbox save file. The default
638 shall be nohold.
639 ignore Ignore interrupts while entering messages. The default shall
641 be noignore.
642 ignoreeof Ignore normal end-of-file during message input. Input can be
644 terminated only by entering a <period> ('.') on a line by
645 itself or by the ~. command escape. The default shall be
646 noignoreeof. See also dot above.
647 indentprefix=string
649 A string that shall be added as a prefix to each line that is
650 inserted into the message by the ~m command escape. This
651 variable shall default to one <tab>.
652 keep When a system mailbox, secondary mailbox, or mbox is empty,
654 truncate it to zero length instead of removing it. The
655 default shall be nokeep.
656 keepsave Keep the messages that have been saved from the system mail‐
658 box into other files in the file designated by the variable
659 MBOX, instead of deleting them. The default shall be nokeep‐
660 save.
661 metoo Suppress the deletion of the login name of the user from the
663 recipient list when replying to a message or sending to a
664 group. The default shall be nometoo.
665 onehop When responding to a message that was originally sent to sev‐
667 eral recipients, the other recipient addresses are normally
668 forced to be relative to the originating author's machine for
669 the response. This flag disables alteration of the recipi‐
670 ents' addresses, improving efficiency in a network where all
671 machines can send directly to all other machines (that is,
672 one hop away). The default shall be noonehop.
673 outfolder Cause the files used to record outgoing messages to be
675 located in the directory specified by the folder variable
676 unless the pathname is absolute. The default shall be noout‐
677 folder. See the record variable.
678 page Insert a <form-feed> after each message sent through the pipe
680 created by the pipe command. The default shall be nopage.
681 prompt=string
683 Set the command-mode prompt to string. If string is null or
684 if noprompt is set, no prompting shall occur. The default
685 shall be to prompt with the string "? ".
686 quiet Refrain from writing the opening message and version when
688 entering mailx. The default shall be noquiet.
689 record=file
691 Record all outgoing mail in the file with the pathname file.
692 The default shall be norecord. See also outfolder above.
693 save Enable saving of messages in the dead-letter file on inter‐
695 rupt or delivery error. See the variable DEAD for the loca‐
696 tion of the dead-letter file. The default shall be save.
697 screen=number
699 Set the number of lines in a screenful of headers for the
700 headers and z commands. If screen is not specified, a value
701 based on the terminal type identified by the TERM environment
702 variable, the window size, the baud rate, or some combination
703 of these shall be used.
704 sendwait Wait for the background mailer to finish before returning.
706 The default shall be nosendwait.
707 showto When the sender of the message was the user who is invoking
709 mailx, write the information from the To: line instead of the
710 From: line in the header summary. The default shall be
711 noshowto.
712 sign=string
714 Set the variable inserted into the text of a message when the
715 ~a command escape is given. The default shall be nosign. The
716 character sequences '\t' and '\n' shall be recognized in the
717 variable as <tab> and <newline> characters, respectively.
718 (See also ~i in Command Escapes in mailx.)
719 Sign=string
721 Set the variable inserted into the text of a message when the
722 ~A command escape is given. The default shall be noSign. The
723 character sequences '\t' and '\n' shall be recognized in the
724 variable as <tab> and <newline> characters, respectively.
725 toplines=number
727 Set the number of lines of the message to write with the top
728 command. The default shall be 5.
729 Commands in mailx
731 The following mailx commands shall be provided. In the following list,
732 header refers to lines from the message header, as shown in the OUTPUT
733 FILES section. Header-line refers to lines within the header that
734 begin with one or more non-white-space characters, immediately followed
735 by a <colon> and white space and continuing until the next line begin‐
736 ning with a non-white-space character or an empty line. Header-field
737 refers to the portion of a header line prior to the first <colon> in
738 that line.
739 For each of the commands listed below, the command can be entered as
741 the abbreviation (those characters in the Synopsis command word preced‐
742 ing the '['), the full command (all characters shown for the command
743 word, omitting the '[' and ']'), or any truncation of the full command
744 down to the abbreviation. For example, the exit command (shown as
745 ex[it] in the Synopsis) can be entered as ex, exi, or exit.
746 The arguments to commands can be quoted, using the following methods:
748 * An argument can be enclosed between paired double-quotes ("") or
750 single-quotes (''); any white space, shell word expansion, or
751 <backslash> characters within the quotes shall be treated literally
752 as part of the argument. A double-quote shall be treated literally
753 within single-quotes and vice versa. These special properties of
754 the <quotation-mark> characters shall occur only when they are
755 paired at the beginning and end of the argument.
756 * A <backslash> outside of the enclosing quotes shall be discarded
758 and the following character treated literally as part of the argu‐
759 ment.
760 * An unquoted <backslash> at the end of a command line shall be dis‐
762 carded and the next line shall continue the command.
763 Filenames, where expected, shall be subjected to the following trans‐
765 formations, in sequence:
766 * If the filename begins with an unquoted <plus-sign>, and the folder
768 variable is defined (see the folder variable), the <plus-sign>
769 shall be replaced by the value of the folder variable followed by a
770 <slash>. If the folder variable is unset or is set to null, the
771 filename shall be unchanged.
772 * Shell word expansions shall be applied to the filename (see Section
774 2.6, Word Expansions). If more than a single pathname results from
775 this expansion and the command is expecting one file, the effects
776 are unspecified.
777 Declare Aliases
779 Synopsis:
780 a[lias] [alias [address...]]
781 g[roup] [alias [address...]]
782 Add the given addresses to the alias specified by alias. The names
784 shall be substituted when alias is used as a recipient address speci‐
785 fied by the user in an outgoing message (that is, other recipients
786 addressed indirectly through the reply command shall not be substituted
787 in this manner). Mail address alias substitution shall apply only when
788 the alias string is used as a full address; for example, when hlj is an
789 alias, hlj@posix.com does not trigger the alias substitution. If no
790 arguments are given, write a listing of the current aliases to standard
791 output. If only an alias argument is given, write a listing of the
792 specified alias to standard output. These listings need not reflect the
793 same order of addresses that were entered.
794 Declare Alternatives
796 Synopsis:
797 alt[ernates] name...
798 (See also the metoo variable.) Declare a list of alternative names for
800 the user's login. When responding to a message, these names shall be
801 removed from the list of recipients for the response. The comparison of
802 names shall be in a case-insensitive manner. With no arguments, alter‐
803 nates shall write the current list of alternative names.
804 Change Current Directory
806 Synopsis:
807 cd [directory]
808 ch[dir] [directory]
809 Change directory. If directory is not specified, the contents of HOME
811 shall be used.
812 Copy Messages
814 Synopsis:
815 c[opy] [file]
816 c[opy] [msglist] file
817 C[opy] [msglist]
818 Copy messages to the file named by the pathname file without marking
820 the messages as saved. Otherwise, it shall be equivalent to the save
821 command.
822 In the capitalized form, save the specified messages in a file whose
824 name is derived from the author of the message to be saved, without
825 marking the messages as saved. Otherwise, it shall be equivalent to the
826 Save command.
827 Delete Messages
829 Synopsis:
830 d[elete] [msglist]
831 Mark messages for deletion from the mailbox. The deletions shall not
833 occur until mailx quits (see the quit command) or changes mailboxes
834 (see the folder command). If autoprint is set and there are messages
835 remaining after the delete command, the current message shall be writ‐
836 ten as described for the print command (see the print command); other‐
837 wise, the mailx prompt shall be written.
838 Discard Header Fields
840 Synopsis:
841 di[scard] [header-field...]
842 ig[nore] [header-field...]
843 Suppress the specified header fields when writing messages. Specified
845 header-fields shall be added to the list of suppressed header fields.
846 Examples of header fields to ignore are status and cc. The fields
847 shall be included when the message is saved. The Print and Type com‐
848 mands shall override this command. The comparison of header fields
849 shall be in a case-insensitive manner. If no arguments are specified,
850 write a list of the currently suppressed header fields to standard out‐
851 put; the listing need not reflect the same order of header fields that
852 were entered.
853 If both retain and discard commands are given, discard commands shall
855 be ignored.
856 Delete Messages and Display
858 Synopsis:
859 dp [msglist]
860 dt [msglist]
861 Delete the specified messages as described for the delete command,
863 except that the autoprint variable shall have no effect, and the cur‐
864 rent message shall be written only if it was set to a message after the
865 last message deleted by the command. Otherwise, an informational mes‐
866 sage to the effect that there are no further messages in the mailbox
867 shall be written, followed by the mailx prompt.
868 Echo a String
870 Synopsis:
871 ec[ho] string ...
872 Echo the given strings, equivalent to the shell echo utility.
874 Edit Messages
876 Synopsis:
877 e[dit] [msglist]
878 Edit the given messages. The messages shall be placed in a temporary
880 file and the utility named by the EDITOR variable is invoked to edit
881 each file in sequence. The default EDITOR is unspecified.
882 The edit command does not modify the contents of those messages in the
884 mailbox.
885 Exit
887 Synopsis:
888 ex[it]
889 x[it]
890 Exit from mailx without changing the mailbox. No messages shall be
892 saved in the mbox (see also quit).
893 Change Folder
895 Synopsis:
896 fi[le] [file]
897 fold[er] [file]
898 Quit (see the quit command) from the current file of messages and read
900 in the file named by the pathname file. If no argument is given, the
901 name and status of the current mailbox shall be written.
902 Several unquoted special characters shall be recognized when used as
904 file names, with the following substitutions:
905 % The system mailbox for the invoking user.
907 %user The system mailbox for user.
909 # The previous file.
911 & The current mbox.
913 +file The named file in the folder directory. (See the folder vari‐
915 able.)
916 The default file shall be the current mailbox.
918 Display List of Folders
920 Synopsis:
921 folders
922 Write the names of the files in the directory set by the folder vari‐
924 able. The command specified by the LISTER environment variable shall be
925 used (see the ENVIRONMENT VARIABLES section).
926 Follow Up Specified Messages
928 Synopsis:
929 fo[llowup] [message]
930 F[ollowup] [msglist]
931 In the lowercase form, respond to a message, recording the response in
933 a file whose name is derived from the author of the message. See also
934 the save and copy commands and outfolder.
935 In the capitalized form, respond to the first message in the msglist,
937 sending the message to the author of each message in the msglist. The
938 subject line shall be taken from the first message and the response
939 shall be recorded in a file whose name is derived from the author of
940 the first message. See also the Save and Copy commands and outfolder.
941 Both forms shall override the record variable, if set.
943 Display Header Summary for Specified Messages
945 Synopsis:
946 f[rom] [msglist]
947 Write the header summary for the specified messages.
949 Display Header Summary
951 Synopsis:
952 h[eaders] [message]
953 Write the page of headers that includes the message specified. If the
955 message argument is not specified, the current message shall not
956 change. However, if the message argument is specified, the current
957 message shall become the message that appears at the top of the page of
958 headers that includes the message specified. The screen variable sets
959 the number of headers per page. See also the z command.
960 Help
962 Synopsis:
963 hel[p]
964 ?
965 Write a summary of commands.
967 Hold Messages
969 Synopsis:
970 ho[ld] [msglist]
971 pre[serve] [msglist]
972 Mark the messages in msglist to be retained in the mailbox when mailx
974 terminates. This shall override any commands that might previously have
975 marked the messages to be deleted. During the current invocation of
976 mailx, only the delete, dp, or dt commands shall remove the preserve
977 marking of a message.
978 Execute Commands Conditionally
980 Synopsis:
981 i[f] s|r
982 mail-commands
983 el[se]
984 mail-commands
985 en[dif]
986 Execute commands conditionally, where if s executes the following mail-
988 commands, up to an else or endif, if the program is in Send Mode, and
989 if r shall cause the mail-commands to be executed only in Receive Mode.
990 List Available Commands
992 Synopsis:
993 l[ist]
994 Write a list of all commands available. No explanation shall be given.
996 Mail a Message
998 Synopsis:
999 m[ail] address...
1000 Mail a message to the specified addresses or aliases.
1002 Direct Messages to mbox
1004 Synopsis:
1005 mb[ox] [msglist]
1006 Arrange for the given messages to end up in the mbox save file when
1008 mailx terminates normally. See MBOX. See also the exit and quit com‐
1009 mands.
1010 Process Next Specified Message
1012 Synopsis:
1013 n[ext] [message]
1014 If the current message has not been written (for example, by the print
1016 command) since mailx started or since any other message was the current
1017 message, behave as if the print command was entered. Otherwise, if
1018 there is an undeleted message after the current message, make it the
1019 current message and behave as if the print command was entered. Other‐
1020 wise, an informational message to the effect that there are no further
1021 messages in the mailbox shall be written, followed by the mailx prompt.
1022 Should the current message location be the result of an immediately
1023 preceding hold, mbox, preserve, or touch command, next will act as if
1024 the current message has already been written.
1025 Pipe Message
1027 Synopsis:
1028 pi[pe] [[msglist] command]
1029 | [[msglist] command]
1030 Pipe the messages through the given command by invoking the command
1032 interpreter specified by SHELL with two arguments: −c and command.
1033 (See also sh −c.) The application shall ensure that the command is
1034 given as a single argument. Quoting, described previously, can be used
1035 to accomplish this. If no arguments are given, the current message
1036 shall be piped through the command specified by the value of the cmd
1037 variable. If the page variable is set, a <form-feed> shall be inserted
1038 after each message.
1039 Display Message with Headers
1041 Synopsis:
1042 P[rint] [msglist]
1043 T[ype] [msglist]
1044 Write the specified messages, including all header lines, to standard
1046 output. Override suppression of lines by the discard, ignore, and
1047 retain commands. If crt is set, the messages longer than the number of
1048 lines specified by the crt variable shall be paged through the command
1049 specified by the PAGER environment variable.
1050 Display Message
1052 Synopsis:
1053 p[rint] [msglist]
1054 t[ype] [msglist]
1055 Write the specified messages to standard output. If crt is set, the
1057 messages longer than the number of lines specified by the crt variable
1058 shall be paged through the command specified by the PAGER environment
1059 variable.
1060 Quit
1062 Synopsis:
1063 q[uit]
1064 end-of-file
1065 Terminate mailx, storing messages that were read in mbox (if the cur‐
1067 rent mailbox is the system mailbox and unless hold is set), deleting
1068 messages that have been explicitly saved (unless keepsave is set), dis‐
1069 carding messages that have been deleted, and saving all remaining mes‐
1070 sages in the mailbox.
1071 Reply to a Message List
1073 Synopsis:
1074 R[eply] [msglist]
1075 R[espond] [msglist]
1076 Mail a reply message to the sender of each message in the msglist. The
1078 subject line shall be formed by concatenating Re:<space> (unless it
1079 already begins with that string) and the subject from the first mes‐
1080 sage. If record is set to a filename, the response shall be saved at
1081 the end of that file.
1082 See also the flipr variable.
1084 Reply to a Message
1086 Synopsis:
1087 r[eply] [message]
1088 r[espond] [message]
1089 Mail a reply message to all recipients included in the header of the
1091 message. The subject line shall be formed by concatenating Re:<space>
1092 (unless it already begins with that string) and the subject from the
1093 message. If record is set to a filename, the response shall be saved at
1094 the end of that file.
1095 See also the flipr variable.
1097 Retain Header Fields
1099 Synopsis:
1100 ret[ain] [header-field...]
1101 Retain the specified header fields when writing messages. This command
1103 shall override all discard and ignore commands. The comparison of
1104 header fields shall be in a case-insensitive manner. If no arguments
1105 are specified, write a list of the currently retained header fields to
1106 standard output; the listing need not reflect the same order of header
1107 fields that were entered.
1108 Save Messages
1110 Synopsis:
1111 s[ave] [file]
1112 s[ave] [msglist] file
1113 S[ave] [msglist]
1114 Save the specified messages in the file named by the pathname file, or
1116 the mbox if the file argument is omitted. The file shall be created if
1117 it does not exist; otherwise, the messages shall be appended to the
1118 file. The message shall be put in the state saved, and shall behave as
1119 specified in the description of the saved state when the current mail‐
1120 box is exited by the quit or file command.
1121 In the capitalized form, save the specified messages in a file whose
1123 name is derived from the author of the first message. The name of the
1124 file shall be taken to be the author's name with all network addressing
1125 stripped off. See also the Copy, followup, and Followup commands and
1126 outfolder variable.
1127 Set Variables
1129 Synopsis:
1130 se[t] [name[=[string]] ...] [name=number ...] [noname ...]
1131 Define one or more variables called name. The variable can be given a
1133 null, string, or numeric value. Quoting and <backslash>-escapes can
1134 occur anywhere in string, as described previously, as if the string
1135 portion of the argument were the entire argument. The forms name and
1136 name= shall be equivalent to name="" for variables that take string
1137 values. The set command without arguments shall write a list of all
1138 defined variables and their values. The no name form shall be equiva‐
1139 lent to unset name.
1140 Invoke a Shell
1142 Synopsis:
1143 sh[ell]
1144 Invoke an interactive command interpreter (see also SHELL).
1146 Display Message Size
1148 Synopsis:
1149 si[ze] [msglist]
1150 Write the size in bytes of each of the specified messages.
1152 Read mailx Commands From a File
1154 Synopsis:
1155 so[urce] file
1156 Read and execute commands from the file named by the pathname file and
1158 return to command mode.
1159 Display Beginning of Messages
1161 Synopsis:
1162 to[p] [msglist]
1163 Write the top few lines of each of the specified messages. If the
1165 toplines variable is set, it is taken as the number of lines to write.
1166 The default shall be 5.
1167 Touch Messages
1169 Synopsis:
1170 tou[ch] [msglist]
1171 Touch the specified messages. If any message in msglist is not specifi‐
1173 cally deleted nor saved in a file, it shall be placed in the mbox upon
1174 normal termination. See exit and quit.
1175 Delete Aliases
1177 Synopsis:
1178 una[lias] [alias]...
1179 Delete the specified alias names. If a specified alias does not exist,
1181 the results are unspecified.
1182 Undelete Messages
1184 Synopsis:
1185 u[ndelete] [msglist]
1186 Change the state of the specified messages from deleted to read. If
1188 autoprint is set, the last message of those restored shall be written.
1189 If msglist is not specified, the message shall be selected as follows:
1190 * If there are any deleted messages that follow the current message,
1192 the first of these shall be chosen.
1193 * Otherwise, the last deleted message that also precedes the current
1195 message shall be chosen.
1196 Unset Variables
1198 Synopsis:
1199 uns[et] name...
1200 Cause the specified variables to be erased.
1202 Edit Message with Full-Screen Editor
1204 Synopsis:
1205 v[isual] [msglist]
1206 Edit the given messages with a screen editor. Each message shall be
1208 placed in a temporary file, and the utility named by the VISUAL vari‐
1209 able shall be invoked to edit each file in sequence. The default editor
1210 shall be vi.
1211 The visual command does not modify the contents of those messages in
1213 the mailbox.
1214 Write Messages to a File
1216 Synopsis:
1217 w[rite] [msglist] file
1218 Write the given messages to the file specified by the pathname file,
1220 minus the message header. Otherwise, it shall be equivalent to the save
1221 command.
1222 Scroll Header Display
1224 Synopsis:
1225 z[+|−]
1226 Scroll the header display forward (if '+' is specified or if no option
1228 is specified) or backward (if '−' is specified) one screenful. The num‐
1229 ber of headers written shall be set by the screen variable.
1230 Invoke Shell Command
1232 Synopsis:
1233 !command
1234 Invoke the command interpreter specified by SHELL with two arguments:
1236 −c and command. (See also sh −c.) If the bang variable is set, each
1237 unescaped occurrence of '!' in command shall be replaced with the com‐
1238 mand executed by the previous ! command or ~! command escape.
1239 Null Command
1241 Synopsis:
1242 # comment
1243 This null command (comment) shall be ignored by mailx.
1245 Display Current Message Number
1247 Synopsis:
1248 =
1249 Write the current message number.
1251 Command Escapes in mailx
1253 The following commands can be entered only from input mode, by begin‐
1254 ning a line with the escape character (by default, <tilde> ('~')). See
1255 the escape variable description for changing this special character.
1256 The format for the commands shall be:
1257 <escape-character><command-char><separator>[<arguments>]
1259 where the <separator> can be zero or more <blank> characters.
1261 In the following descriptions, the application shall ensure that the
1263 argument command (but not mailx-command) is a shell command string. Any
1264 string acceptable to the command interpreter specified by the SHELL
1265 variable when it is invoked as SHELL −c command_string shall be valid.
1266 The command can be presented as multiple arguments (that is, quoting is
1267 not required).
1268 Command escapes that are listed with msglist or mailx-command arguments
1270 are invalid in Send Mode and produce unspecified results.
1271 ~! command
1273 Invoke the command interpreter specified by SHELL with two
1274 arguments: −c and command; and then return to input mode. If
1275 the bang variable is set, each unescaped occurrence of '!'
1276 in command shall be replaced with the command executed by the
1277 previous ! command or ~! command escape.
1278 ~. Simulate end-of-file (terminate message input).
1280 ~: mailx-command, ~_ mailx-command
1282 Perform the command-level request.
1283 ~? Write a summary of command escapes.
1285 ~A This shall be equivalent to ~i Sign.
1287 ~a This shall be equivalent to ~i sign.
1289 ~b name...
1291 Add the names to the blind carbon copy (Bcc) list.
1292 ~c name...
1294 Add the names to the carbon copy (Cc) list.
1295 ~d Read in the dead-letter file. See DEAD for a description of
1297 this file.
1298 ~e Invoke the editor, as specified by the EDITOR environment
1300 variable, on the partial message.
1301 ~f [msglist]
1303 Forward the specified messages. The specified messages shall
1304 be inserted into the current message without alteration. This
1305 command escape also shall insert message headers into the
1306 message with field selection affected by the discard, ignore,
1307 and retain commands.
1308 ~F [msglist]
1310 This shall be the equivalent of the ~f command escape, except
1311 that all headers shall be included in the message, regardless
1312 of previous discard, ignore, and retain commands.
1313 ~h If standard input is a terminal, prompt for a Subject line
1315 and the To, Cc, and Bcc lists. Other implementation-defined
1316 headers may also be presented for editing. If the field is
1317 written with an initial value, it can be edited as if it had
1318 just been typed.
1319 ~i string Insert the value of the named variable, followed by a <new‐
1321 line>, into the text of the message. If the string is unset
1322 or null, the message shall not be changed.
1323 ~m [msglist]
1325 Insert the specified messages into the message, prefixing
1326 non-empty lines with the string in the indentprefix variable.
1327 This command escape also shall insert message headers into
1328 the message, with field selection affected by the discard,
1329 ignore, and retain commands.
1330 ~M [msglist]
1332 This shall be the equivalent of the ~m command escape, except
1333 that all headers shall be included in the message, regardless
1334 of previous discard, ignore, and retain commands.
1335 ~p Write the message being entered. If the message is longer
1337 than crt lines (see Internal Variables in mailx), the output
1338 shall be paginated as described for the PAGER variable.
1339 ~q Quit (see the quit command) from input mode by simulating an
1341 interrupt. If the body of the message is not empty, the par‐
1342 tial message shall be saved in the dead-letter file. See DEAD
1343 for a description of this file.
1344 ~r file, ~< file, ~r !command, ~< !command
1346 Read in the file specified by the pathname file. If the
1347 argument begins with an <exclamation-mark> ('!'), the rest of
1348 the string shall be taken as an arbitrary system command; the
1349 command interpreter specified by SHELL shall be invoked with
1350 two arguments: −c and command. The standard output of com‐
1351 mand shall be inserted into the message.
1352 ~s string Set the subject line to string.
1354 ~t name...
1356 Add the given names to the To list.
1357 ~v Invoke the full-screen editor, as specified by the VISUAL
1359 environment variable, on the partial message.
1360 ~w file Write the partial message, without the header, onto the file
1362 named by the pathname file. The file shall be created or the
1363 message shall be appended to it if the file exists.
1364 ~x Exit as with ~q, except the message shall not be saved in the
1366 dead-letter file.
1367 ~| command
1369 Pipe the body of the message through the given command by
1370 invoking the command interpreter specified by SHELL with two
1371 arguments: −c and command. If the command returns a success‐
1372 ful exit status, the standard output of the command shall
1373 replace the message. Otherwise, the message shall remain
1374 unchanged. If the command fails, an error message giving the
1375 exit status shall be written.
1376
1378 When the −e option is specified, the following exit values are
1379 returned:
1380 0 Mail was found.
1382 >0 Mail was not found or an error occurred.
1384 Otherwise, the following exit values are returned:
1386 0 Successful completion; note that this status implies that all
1388 messages were sent, but it gives no assurances that any of them
1389 were actually delivered.
1390 >0 An error occurred.
1392
1394 When in input mode (Receive Mode) or Send Mode:
1395 * If an error is encountered processing an input line beginning with
1397 a <tilde> ('~') character, (see Command Escapes in mailx), a diag‐
1398 nostic message shall be written to standard error, and the message
1399 being composed may be modified, but this condition shall not pre‐
1400 vent the message from being sent.
1401 * Other errors shall prevent the sending of the message.
1403 When in command mode:
1405 * Default.
1407 The following sections are informative.
1409
1411 Delivery of messages to remote systems requires the existence of commu‐
1412 nication paths to such systems. These need not exist.
1413 Input lines are limited to {LINE_MAX} bytes, but mailers between sys‐
1415 tems may impose more severe line-length restrictions. This volume of
1416 POSIX.1‐2008 does not place any restrictions on the length of messages
1417 handled by mailx, and for delivery of local messages the only limita‐
1418 tions should be the normal problems of available disk space for the
1419 target mail file. When sending messages to external machines, applica‐
1420 tions are advised to limit messages to less than 100000 bytes because
1421 some mail gateways impose message-length restrictions.
1422 The format of the system mailbox is intentionally unspecified. Not all
1424 systems implement system mailboxes as flat files, particularly with the
1425 advent of multimedia mail messages. Some system mailboxes may be multi‐
1426 ple files, others records in a database. The internal format of the
1427 messages themselves is specified with the historical format from Ver‐
1428 sion 7, but only after the messages have been saved in some file other
1429 than the system mailbox. This was done so that many historical applica‐
1430 tions expecting text-file mailboxes are not broken.
1431 Some new formats for messages can be expected in the future, probably
1433 including binary data, bit maps, and various multimedia objects. As
1434 described here, mailx is not prohibited from handling such messages,
1435 but it must store them as text files in secondary mailboxes (unless
1436 some extension, such as a variable or command line option, is used to
1437 change the stored format). Its method of doing so is implementation-
1438 defined and might include translating the data into text file-compati‐
1439 ble or readable form or omitting certain portions of the message from
1440 the stored output.
1441 The discard and ignore commands are not inverses of the retain command.
1443 The retain command discards all header-fields except those explicitly
1444 retained. The discard command keeps all header-fields except those
1445 explicitly discarded. If headers exist on the retained header list,
1446 discard and ignore commands are ignored.
1447
1449 None.
1450
1452 The standard developers felt strongly that a method for applications to
1453 send messages to specific users was necessary. The obvious example is a
1454 batch utility, running non-interactively, that wishes to communicate
1455 errors or results to a user. However, the actual format, delivery mech‐
1456 anism, and method of reading the message are clearly beyond the scope
1457 of this volume of POSIX.1‐2008.
1458 The intent of this command is to provide a simple, portable interface
1460 for sending messages non-interactively. It merely defines a ``front-
1461 end'' to the historical mail system. It is suggested that implementa‐
1462 tions explicitly denote the sender and recipient in the body of the
1463 delivered message. Further specification of formats for either the mes‐
1464 sage envelope or the message itself were deliberately not made, as the
1465 industry is in the midst of changing from the current standards to a
1466 more internationalized standard and it is probably incorrect, at this
1467 time, to require either one.
1468 Implementations are encouraged to conform to the various delivery mech‐
1470 anisms described in the CCITT X.400 standards or to the equivalent
1471 Internet standards, described in Internet Request for Comment (RFC)
1472 documents RFC 819, RFC 822, RFC 920, RFC 921, and RFC 1123.
1473 Many historical systems modified each body line that started with From
1475 by prefixing the 'F' with '>'. It is unnecessary, but allowed, to do
1476 that when the string does not follow a blank line because it cannot be
1477 confused with the next header.
1478 The edit and visual commands merely edit the specified messages in a
1480 temporary file. They do not modify the contents of those messages in
1481 the mailbox; such a capability could be added as an extension, such as
1482 by using different command names.
1483 The restriction on a subject line being {LINE_MAX}−10 bytes is based on
1485 the historical format that consumes 10 bytes for Subject: and the
1486 trailing <newline>. Many historical mailers that a message may
1487 encounter on other systems are not able to handle lines that long, how‐
1488 ever.
1489 Like the utilities logger and lp, mailx admittedly is difficult to
1491 test. This was not deemed sufficient justification to exclude this
1492 utility from this volume of POSIX.1‐2008. It is also arguable that it
1493 is, in fact, testable, but that the tests themselves are not portable.
1494 When mailx is being used by an application that wishes to receive the
1496 results as if none of the User Portability Utilities option features
1497 were supported, the DEAD environment variable must be set to /dev/null.
1498 Otherwise, it may be subject to the file creations described in mailx
1499 ASYNCHRONOUS EVENTS. Similarly, if the MAILRC environment variable is
1500 not set to /dev/null, historical versions of mailx and Mail read ini‐
1501 tialization commands from a file before processing begins. Since the
1502 initialization that a user specifies could alter the contents of mes‐
1503 sages an application is trying to send, such applications must set
1504 MAILRC to /dev/null.
1505 The description of LC_TIME uses ``may affect'' because many historical
1507 implementations do not or cannot manipulate the date and time strings
1508 in the incoming mail headers. Some headers found in incoming mail do
1509 not have enough information to determine the timezone in which the mail
1510 originated, and, therefore, mailx cannot convert the date and time
1511 strings into the internal form that then is parsed by routines like
1512 strftime() that can take LC_TIME settings into account. Changing all
1513 these times to a user-specified format is allowed, but not required.
1514 The paginator selected when PAGER is null or unset is partially unspec‐
1516 ified to allow the System V historical practice of using pg as the
1517 default. Bypassing the pagination function, such as by declaring that
1518 cat is the paginator, would not meet with the intended meaning of this
1519 description. However, any ``portable user'' would have to set PAGER
1520 explicitly to get his or her preferred paginator on all systems. The
1521 paginator choice was made partially unspecified, unlike the VISUAL edi‐
1522 tor choice (mandated to be vi) because most historical pagers follow a
1523 common theme of user input, whereas editors differ dramatically.
1524 Options to specify addresses as cc (carbon copy) or bcc (blind carbon
1526 copy) were considered to be format details and were omitted.
1527 A zero exit status implies that all messages were sent, but it gives no
1529 assurances that any of them were actually delivered. The reliability
1530 of the delivery mechanism is unspecified and is an appropriate market‐
1531 ing distinction between systems.
1532 In order to conform to the Utility Syntax Guidelines, a solution was
1534 required to the optional file option-argument to −f. By making file an
1535 operand, the guidelines are satisfied and users remain portable. How‐
1536 ever, it does force implementations to support usage such as:
1537 mailx −fin mymail.box
1539 The no name method of unsetting variables is not present in all histor‐
1541 ical systems, but it is in System V and provides a logical set of com‐
1542 mands corresponding to the format of the display of options from the
1543 mailx set command without arguments.
1544 The ask and asksub variables are the names selected by BSD and System
1546 V, respectively, for the same feature. They are synonyms in this volume
1547 of POSIX.1‐2008.
1548 The mailx echo command was not documented in the BSD version and has
1550 been omitted here because it is not obviously useful for interactive
1551 users.
1552 The default prompt on the System V mailx is a <question-mark>, on BSD
1554 Mail an <ampersand>. Since this volume of POSIX.1‐2008 chose the mailx
1555 name, it kept the System V default, assuming that BSD users would not
1556 have difficulty with this minor incompatibility (that they can over‐
1557 ride).
1558 The meanings of r and R are reversed between System V mailx and SunOS
1560 Mail. Once again, since this volume of POSIX.1‐2008 chose the mailx
1561 name, it kept the System V default, but allows the SunOS user to
1562 achieve the desired results using flipr, an internal variable in System
1563 V mailx, although it has not been documented in the SVID.
1564 The indentprefix variable, the retain and unalias commands, and the ~F
1566 and ~M command escapes were adopted from 4.3 BSD Mail.
1567 The version command was not included because no sufficiently general
1569 specification of the version information could be devised that would
1570 still be useful to a portable user. This command name should be used by
1571 suppliers who wish to provide version information about the mailx com‐
1572 mand.
1573 The ``implementation-specific (unspecified) system start-up file'' his‐
1575 torically has been named /etc/mailx.rc, but this specific name and
1576 location are not required.
1577 The intent of the wording for the next command is that if any command
1579 has already displayed the current message it should display a following
1580 message, but, otherwise, it should display the current message. Con‐
1581 sider the command sequence:
1582 next 3
1584 delete 3
1585 next
1586 where the autoprint option was not set. The normative text specifies
1588 that the second next command should display a message following the
1589 third message, because even though the current message has not been
1590 displayed since it was set by the delete command, it has been displayed
1591 since the current message was anything other than message number 3.
1592 This does not always match historical practice in some implementations,
1593 where the command file address followed by next (or the default com‐
1594 mand) would skip the message for which the user had searched.
1595
1597 None.
1598
1600 Chapter 2, Shell Command Language, ed, ls, more, vi
1601 The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
1603 Variables, Section 12.2, Utility Syntax Guidelines
1604
1606 Portions of this text are reprinted and reproduced in electronic form
1607 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
1608 -- Portable Operating System Interface (POSIX), The Open Group Base
1609 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
1610 cal and Electronics Engineers, Inc and The Open Group. (This is
1611 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
1612 event of any discrepancy between this version and the original IEEE and
1613 The Open Group Standard, the original IEEE and The Open Group Standard
1614 is the referee document. The original Standard can be obtained online
1615 at http://www.unix.org/online.html .
1616 Any typographical or formatting errors that appear in this page are
1618 most likely to have been introduced during the conversion of the source
1619 files to man page format. To report such errors, see https://www.ker‐
1620 nel.org/doc/man-pages/reporting_bugs.html .
1621IEEE/The Open Group 2013 MAILX(1P)