1MAILX(P) POSIX Programmer's Manual MAILX(P)
2
6 mailx - process messages
7
9 Send Mode
10 mailx [-s subject] address...
11 Receive Mode
13 mailx -e
14 mailx [-HiNn][-F][-u user]
19 mailx -f[-HiNn][-F][file]
23
26 The mailx utility provides a message sending and receiving facility.
27 It has two major modes, selected by the options used: Send Mode and
28 Receive Mode.
29 On systems that do not support the User Portability Utilities option,
31 an application using mailx shall have the ability to send messages in
32 an unspecified manner (Send Mode). Unless the first character of one or
33 more lines is tilde ( '~' ), all characters in the input message shall
34 appear in the delivered message, but additional characters may be
35 inserted in the message before it is retrieved.
36 On systems supporting the User Portability Utilities option, mail-
38 receiving capabilities and other interactive features, Receive Mode,
39 described below, also shall be enabled.
40 Send Mode
42 Send Mode can be used by applications or users to send messages from
43 the text in standard input.
44 Receive Mode
46 Receive Mode is more oriented towards interactive users. Mail can be
47 read and sent in this interactive mode.
48 When reading mail, mailx provides commands to facilitate saving, delet‐
50 ing, and responding to messages. When sending mail, mailx allows edit‐
51 ing, reviewing, and other modification of the message as it is entered.
52 Incoming mail shall be stored in one or more unspecified locations for
54 each user, collectively called the system mailbox for that user. When
55 mailx is invoked in Receive Mode, the system mailbox shall be the
56 default place to find new mail. As messages are read, they shall be
57 marked to be moved to a secondary file for storage, unless specific
58 action is taken. This secondary file is called the mbox and is normally
59 located in the directory referred to by the HOME environment variable
60 (see MBOX in the ENVIRONMENT VARIABLES section for a description of
61 this file). Messages shall remain in this file until explicitly
62 removed. When the -f option is used to read mail messages from sec‐
63 ondary files, messages shall be retained in those files unless specifi‐
64 cally removed. All three of these locations-system mailbox, mbox, and
65 secondary file-are referred to in this section as simply "mailboxes",
66 unless more specific identification is required.
67
69 The mailx utility shall conform to the Base Definitions volume of
70 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
71 The following options shall be supported. (Only the -s subject option
73 shall be required on all systems. The other options are required only
74 on systems supporting the User Portability Utilities option.)
75 -e Test for the presence of mail in the system mailbox. The mailx
77 utility shall write nothing and exit with a successful return
78 code if there is mail to read.
79 -f Read messages from the file named by the file operand instead of
81 the system mailbox. (See also folder.) If no file operand is
82 specified, read messages from mbox instead of the system mail‐
83 box.
84 -F Record the message in a file named after the first recipient.
86 The name is the login-name portion of the address found first on
87 the To: line in the mail header. Overrides the record variable,
88 if set (see Internal Variables in mailx .)
89 -H Write a header summary only.
91 -i Ignore interrupts. (See also ignore.)
93 -n Do not initialize from the system default start-up file. See the
95 EXTENDED DESCRIPTION section.
96 -N Do not write an initial header summary.
98 -s subject
100 Set the Subject header field to subject. All characters in the
101 subject string shall appear in the delivered message. The
102 results are unspecified if subject is longer than {LINE_MAX} -
103 10 bytes or contains a <newline>.
104 -u user
106 Read the system mailbox of the login name user. This shall only
107 be successful if the invoking user has the appropriate privi‐
108 leges to read the system mailbox of that user.
109
112 The following operands shall be supported:
113 address
115 Addressee of message. When -n is specified and no user start-up
116 files are accessed (see the EXTENDED DESCRIPTION section), the
117 user or application shall ensure this is an address to pass to
118 the mail delivery system. Any system or user start-up files may
119 enable aliases (see alias under Commands in mailx ) that may
120 modify the form of address before it is passed to the mail
121 delivery system.
122 file A pathname of a file to be read instead of the system mailbox
124 when -f is specified. The meaning of the file option-argument
125 shall be affected by the contents of the folder internal vari‐
126 able; see Internal Variables in mailx .
127
130 When mailx is invoked in Send Mode (the first synopsis line), standard
131 input shall be the message to be delivered to the specified addresses.
132 When in Receive Mode, user commands shall be accepted from stdin. If
133 the User Portability Utilities option is not supported, standard input
134 lines beginning with a tilde ( '~' ) character produce unspecified
135 results.
136 If the User Portability Utilities option is supported, then in both
138 Send and Receive Modes, standard input lines beginning with the escape
139 character (usually tilde ( '~' )) shall affect processing as described
140 in Command Escapes in mailx .
141
143 When mailx is used as described by this volume of IEEE Std 1003.1-2001,
144 the file option-argument (see the -f option) and the mbox shall be text
145 files containing mail messages, formatted as described in the OUTPUT
146 FILES section. The nature of the system mailbox is unspecified; it need
147 not be a file.
148
150 The following environment variables shall affect the execution of
151 mailx:
152 DEAD Determine the pathname of the file in which to save partial mes‐
154 sages in case of interrupts or delivery errors. The default
155 shall be dead.letter in the directory named by the HOME vari‐
156 able. The behavior of mailx in saving partial messages is
157 unspecified if the User Portability Utilities option is not sup‐
158 ported and DEAD is not defined with the value /dev/null.
159 EDITOR Determine the name of a utility to invoke when the edit (see
161 Commands in mailx ) or ~e (see Command Escapes in mailx ) com‐
162 mand is used. The default editor is unspecified. On XSI-con‐
163 formant systems it is ed. The effects of this variable are
164 unspecified if the User Portability Utilities option is not sup‐
165 ported.
166 HOME Determine the pathname of the user's home directory.
168 LANG Provide a default value for the internationalization variables
170 that are unset or null. (See the Base Definitions volume of
171 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
172 ables for the precedence of internationalization variables used
173 to determine the values of locale categories.)
174 LC_ALL If set to a non-empty string value, override the values of all
176 the other internationalization variables.
177 LC_CTYPE
179 Determine the locale for the interpretation of sequences of
180 bytes of text data as characters (for example, single-byte as
181 opposed to multi-byte characters in arguments and input files)
182 and the handling of case-insensitive address and header-field
183 comparisons.
184 LC_TIME
186 Determine the format and contents of the date and time strings
187 written by mailx.
188 LC_MESSAGES
190 Determine the locale that should be used to affect the format
191 and contents of diagnostic messages written to standard error
192 and informative messages written to standard output.
193 LISTER Determine a string representing the command for writing the con‐
195 tents of the folder directory to standard output when the fold‐
196 ers command is given (see folders in Commands in mailx ). Any
197 string acceptable as a command_string operand to the sh -c com‐
198 mand shall be valid. If this variable is null or not set, the
199 output command shall be ls. The effects of this variable are
200 unspecified if the User Portability Utilities option is not sup‐
201 ported.
202 MAILRC Determine the pathname of the start-up file. The default shall
204 be .mailrc in the directory referred to by the HOME environment
205 variable. The behavior of mailx is unspecified if the User
206 Portability Utilities option is not supported and MAILRC is not
207 defined with the value /dev/null.
208 MBOX Determine a pathname of the file to save messages from the sys‐
210 tem mailbox that have been read. The exit command shall override
211 this function, as shall saving the message explicitly in another
212 file. The default shall be mbox in the directory named by the
213 HOME variable. The effects of this variable are unspecified if
214 the User Portability Utilities option is not supported.
215 NLSPATH
217 Determine the location of message catalogs for the processing of
218 LC_MESSAGES .
219 PAGER Determine a string representing an output filtering or pagina‐
221 tion command for writing the output to the terminal. Any string
222 acceptable as a command_string operand to the sh -c command
223 shall be valid. When standard output is a terminal device, the
224 message output shall be piped through the command if the mailx
225 internal variable crt is set to a value less the number of lines
226 in the message; see Internal Variables in mailx . If the PAGER
227 variable is null or not set, the paginator shall be either more
228 or another paginator utility documented in the system documenta‐
229 tion. The effects of this variable are unspecified if the User
230 Portability Utilities option is not supported.
231 SHELL Determine the name of a preferred command interpreter. The
233 default shall be sh. The effects of this variable are unspeci‐
234 fied if the User Portability Utilities option is not supported.
235 TERM If the internal variable screen is not specified, determine the
237 name of the terminal type to indicate in an unspecified manner
238 the number of lines in a screenful of headers. If TERM is not
239 set or is set to null, an unspecified default terminal type
240 shall be used and the value of a screenful is unspecified. The
241 effects of this variable are unspecified if the User Portability
242 Utilities option is not supported.
243 TZ This variable may determine the timezone used to calculate date
245 and time strings written by mailx. If TZ is unset or null, an
246 unspecified default timezone shall be used.
247 VISUAL Determine a pathname of a utility to invoke when the visual com‐
249 mand (see Commands in mailx ) or ~v command-escape (see Command
250 Escapes in mailx ) is used. If this variable is null or not set,
251 the full-screen editor shall be vi. The effects of this vari‐
252 able are unspecified if the User Portability Utilities option is
253 not supported.
254
257 When mailx is in Send Mode and standard input is not a terminal, it
258 shall take the standard action for all signals.
259 In Receive Mode, or in Send Mode when standard input is a terminal, if
261 a SIGINT signal is received:
262 1. If in command mode, the current command, if there is one, shall be
264 aborted, and a command-mode prompt shall be written.
265 2. If in input mode:
267 a. If ignore is set, mailx shall write "@\n" , discard the current
269 input line, and continue processing, bypassing the message-
270 abort mechanism described in item 2b.
271 b. If the interrupt was received while sending mail, either when
273 in Receive Mode or in Send Mode, a message shall be written,
274 and another subsequent interrupt, with no other intervening
275 characters typed, shall be required to abort the mail message.
276 If in Receive Mode and another interrupt is received, a com‐
277 mand-mode prompt shall be written. If in Send Mode and another
278 interrupt is received, mailx shall terminate with a non-zero
279 status.
280 In both cases listed in item b, if the message is not empty:
282 i. If save is enabled and the file named by DEAD can be
284 created, the message shall be written to the file named
285 by DEAD . If the file exists, the message shall be
286 written to replace the contents of the file.
287 ii. If save is not enabled, or the file named by DEAD can‐
289 not be created, the message shall not be saved.
290 The mailx utility shall take the standard action for all other signals.
292
294 In command and input modes, all output, including prompts and messages,
295 shall be written to standard output.
296
298 The standard error shall be used only for diagnostic messages.
299
301 Various mailx commands and command escapes can create or add to files,
302 including the mbox, the dead-letter file, and secondary mailboxes. When
303 mailx is used as described in this volume of IEEE Std 1003.1-2001,
304 these files shall be text files, formatted as follows: line beginning
305 with From<space>
306 [one or more header-lines; see Commands in mailx ]
307 empty line
308 [zero or more body lines
309 empty line]
310 [line beginning with From<space>...]
311 where each message begins with the From <space> line shown, preceded by
313 the beginning of the file or an empty line. (The From <space> line is
314 considered to be part of the message header, but not one of the header-
315 lines referred to in Commands in mailx ; thus, it shall not be affected
316 by the discard, ignore, or retain commands.) The formats of the remain‐
317 der of the From <space> line and any additional header lines are
318 unspecified, except that none shall be empty. The format of a message
319 body line is also unspecified, except that no line following an empty
320 line shall start with From <space>; mailx shall modify any such user-
321 entered message body lines (following an empty line and beginning with
322 From <space>) by adding one or more characters to precede the 'F' ; it
323 may add these characters to From <space> lines that are not preceded by
324 an empty line.
325 When a message from the system mailbox or entered by the user is not a
327 text file, it is implementation-defined how such a message is stored in
328 files written by mailx.
329
331 The entire EXTENDED DESCRIPTION section shall apply only to implementa‐
332 tions supporting the User Portability Utilities option.
333 The mailx utility cannot guarantee support for all character encodings
335 in all circumstances. For example, inter-system mail may be restricted
336 to 7-bit data by the underlying network, 8-bit data need not be porta‐
337 ble to non-internationalized systems, and so on. Under these circum‐
338 stances, it is recommended that only characters defined in the
339 ISO/IEC 646:1991 standard International Reference Version (equivalent
340 to ASCII) 7-bit range of characters be used.
341 When mailx is invoked using one of the Receive Mode synopsis forms, it
343 shall write a page of header-summary lines (if -N was not specified and
344 there are messages, see below), followed by a prompt indicating that
345 mailx can accept regular commands (see Commands in mailx ); this is
346 termed command mode. The page of header-summary lines shall contain the
347 first new message if there are new messages, or the first unread mes‐
348 sage if there are unread messages, or the first message. When mailx is
349 invoked using the Send Mode synopsis and standard input is a terminal,
350 if no subject is specified on the command line and the asksub variable
351 is set, a prompt for the subject shall be written. At this point, mailx
352 shall be in input mode. This input mode shall also be entered when
353 using one of the Receive Mode synopsis forms and a reply or new message
354 is composed using the reply, Reply, followup, Followup, or mail com‐
355 mands and standard input is a terminal. When the message is typed and
356 the end of the message is encountered, the message shall be passed to
357 the mail delivery software. Commands can be entered by beginning a line
358 with the escape character (by default, tilde ( '~' )) followed by a
359 single command letter and optional arguments. See Commands in mailx
360 for a summary of these commands. It is unspecified what effect these
361 commands will have if standard input is not a terminal when a message
362 is entered using either the Send Mode synopsis, or the Read Mode com‐
363 mands reply, Reply, followup, Followup, or mail.
364 Note: For notational convenience, this section uses the default escape
366 character, tilde, in all references and examples.
367 At any time, the behavior of mailx shall be governed by a set of envi‐
370 ronmental and internal variables. These are flags and valued parameters
371 that can be set and cleared via the mailx set and unset commands.
372 Regular commands are of the form:
374 [command] [msglist] [argument ...]
377 If no command is specified in command mode, next shall be assumed. In
379 input mode, commands shall be recognized by the escape character, and
380 lines not treated as commands shall be taken as input for the message.
381 In command mode, each message shall be assigned a sequential number,
383 starting with 1.
384 All messages have a state that shall affect how they are displayed in
386 the header summary and how they are retained or deleted upon termina‐
387 tion of mailx. There is at any time the notion of a current message,
388 which shall be marked by a '>' at the beginning of a line in the header
389 summary. When mailx is invoked using one of the Receive Mode synopsis
390 forms, the current message shall be the first new message, if there is
391 a new message, or the first unread message if there is an unread mes‐
392 sage, or the first message if there are any messages, or unspecified if
393 there are no messages in the mailbox. Each command that takes an
394 optional list of messages (msglist) or an optional single message (mes‐
395 sage) on which to operate shall leave the current message set to the
396 highest-numbered message of the messages specified, unless the command
397 deletes messages, in which case the current message shall be set to the
398 first undeleted message (that is, a message not in the deleted state)
399 after the highest-numbered message deleted by the command, if one
400 exists, or the first undeleted message before the highest-numbered mes‐
401 sage deleted by the command, if one exists, or to an unspecified value
402 if there are no remaining undeleted messages. All messages shall be in
403 one of the following states:
404 new The message is present in the system mailbox and has not been
406 viewed by the user or moved to any other state. Messages in
407 state new when mailx quits shall be retained in the system mail‐
408 box.
409 unread The message has been present in the system mailbox for more than
411 one invocation of mailx and has not been viewed by the user or
412 moved to any other state. Messages in state unread when mailx
413 quits shall be retained in the system mailbox.
414 read The message has been processed by one of the following commands:
416 ~f, ~m, ~F, ~M, copy, mbox, next, pipe, print, Print, top, type,
417 Type, undelete. The delete, dp, and dt commands may also cause
418 the next message to be marked as read, depending on the value of
419 the autoprint variable. Messages that are in the system mailbox
420 and in state read when mailx quits shall be saved in the mbox,
421 unless the internal variable hold was set. Messages that are in
422 the mbox or in a secondary mailbox and in state read when mailx
423 quits shall be retained in their current location.
424 deleted
426 The message has been processed by one of the following commands:
427 delete, dp, dt. Messages in state deleted when mailx quits shall
428 be deleted. Deleted messages shall be ignored until mailx quits
429 or changes mailboxes or they are specified to the undelete com‐
430 mand; for example, the message specification / string shall only
431 search the subject lines of messages that have not yet been
432 deleted, unless the command operating on the list of messages is
433 undelete. No deleted message or deleted message header shall be
434 displayed by any mailx command other than undelete.
435 preserved
437 The message has been processed by a preserve command. When mailx
438 quits, the message shall be retained in its current location.
439 saved The message has been processed by one of the following commands:
441 save or write. If the current mailbox is the system mailbox, and
442 the internal variable keepsave is set, messages in the state
443 saved shall be saved to the file designated by the MBOX variable
444 (see the ENVIRONMENT VARIABLES section). If the current mailbox
445 is the system mailbox, messages in the state saved shall be
446 deleted from the current mailbox, when the quit or file command
447 is used to exit the current mailbox.
448 The header-summary line for each message shall indicate the state of
451 the message.
452 Many commands take an optional list of messages ( msglist) on which to
454 operate, which defaults to the current message. A msglist is a list of
455 message specifications separated by <blank>s, which can include:
456 n Message number n.
458 + The next undeleted message, or the next deleted message for the
460 undelete command.
461 - The next previous undeleted message, or the next previous
463 deleted message for the undelete command.
464 . The current message.
466 ^ The first undeleted message, or the first deleted message for
468 the undelete command.
469 $ The last message.
471 * All messages.
473 n-m An inclusive range of message numbers.
475 address
477 All messages from address; any address as shown in a header sum‐
478 mary shall be matchable in this form.
479 /string
481 All messages with string in the subject line (case ignored).
482 :c All messages of type c, where c shall be one of:
484 d
486 Deleted messages.
487 n
489 New messages.
490 o
492 Old messages (any not in state read or new).
493 r
495 Read messages.
496 u
498 Unread messages.
499 Other commands take an optional message ( message) on which to operate,
503 which defaults to the current message. All of the forms allowed for
504 msglist are also allowed for message, but if more than one message is
505 specified, only the first shall be operated on.
506 Other arguments are usually arbitrary strings whose usage depends on
508 the command involved.
509 Start-Up in mailx
511 At start-up time, mailx shall take the following steps in sequence:
512 1. Establish all variables at their stated default values.
514 2. Process command line options, overriding corresponding default val‐
516 ues.
517 3. Import any of the DEAD , EDITOR , MBOX , LISTER , PAGER , SHELL ,
519 or VISUAL variables that are present in the environment, overriding
520 the corresponding default values.
521 4. Read mailx commands from an unspecified system start-up file,
523 unless the -n option is given, to initialize any internal mailx
524 variables and aliases.
525 5. Process the start-up file of mailx commands named in the user
527 MAILRC variable.
528 Most regular mailx commands are valid inside start-up files, the most
530 common use being to set up initial display options and alias lists. The
531 following commands shall be invalid in the start-up file: !, edit,
532 hold, mail, preserve, reply, Reply, shell, visual, Copy, followup, and
533 Followup. Any errors in the start-up file shall either cause mailx to
534 terminate with a diagnostic message and a non-zero status or to con‐
535 tinue after writing a diagnostic message, ignoring the remainder of the
536 lines in the start-up file.
537 A blank line in a start-up file shall be ignored.
539 Internal Variables in mailx
541 The following variables are internal mailx variables. Each internal
542 variable can be set via the mailx set command at any time. The unset
543 and set no name commands can be used to erase variables.
544 In the following list, variables shown as:
546 variable
549 represent Boolean values. Variables shown as:
551 variable=value
554 shall be assigned string or numeric values. For string values, the
556 rules in Commands in mailx concerning filenames and quoting shall also
557 apply.
558 The defaults specified here may be changed by the implementation-
560 defined system start-up file unless the user specifies the -n option.
561 allnet All network names whose login name components match shall be
563 treated as identical. This shall cause the msglist message spec‐
564 ifications to behave similarly. The default shall be noallnet.
565 See also the alternates command and the metoo variable.
566 append Append messages to the end of the mbox file upon termination
568 instead of placing them at the beginning. The default shall be
569 noappend. This variable shall not affect the save command when
570 saving to mbox.
571 ask, asksub
573 Prompt for a subject line on outgoing mail if one is not speci‐
574 fied on the command line with the -s option. The ask and asksub
575 forms are synonyms; the system shall refer to asksub and
576 noasksub in its messages, but shall accept ask and noask as user
577 input to mean asksub and noasksub. It shall not be possible to
578 set both ask and noasksub, or noask and asksub. The default
579 shall be asksub, but no prompting shall be done if standard
580 input is not a terminal.
581 askbcc Prompt for the blind copy list. The default shall be noaskbcc.
583 askcc Prompt for the copy list. The default shall be noaskcc.
585 autoprint
587 Enable automatic writing of messages after delete and undelete
588 commands. The default shall be noautoprint.
589 bang Enable the special-case treatment of exclamation marks ( '!' )
591 in escape command lines; see the escape command and Command
592 Escapes in mailx . The default shall be nobang, disabling the
593 expansion of '!' in the command argument to the ~! command and
594 the ~<! command escape.
595 cmd=command
597 Set the default command to be invoked by the pipe command. The
599 default shall be nocmd.
600 crt=number
602 Pipe messages having more than number lines through the command
603 specified by the value of the PAGER variable. The default shall
604 be nocrt. If it is set to null, the value used is implementa‐
605 tion-defined.
606 debug Enable verbose diagnostics for debugging. Messages are not
608 delivered. The default shall be nodebug.
609 dot When dot is set, a period on a line by itself during message
611 input from a terminal shall also signify end-of-file (in addi‐
612 tion to normal end-of-file). The default shall be nodot. If
613 ignoreeof is set (see below), a setting of nodot shall be
614 ignored and the period is the only method to terminate input
615 mode.
616 escape=c
618 Set the command escape character to be the character 'c' . By
619 default, the command escape character shall be tilde. If escape
620 is unset, tilde shall be used; if it is set to null, command
621 escaping shall be disabled.
622 flipr Reverse the meanings of the R and r commands. The default shall
624 be noflipr.
625 folder=directory
627 The default directory for saving mail files. User-specified
629 filenames beginning with a plus sign ( '+' ) shall be expanded
630 by preceding the filename with this directory name to obtain the
631 real pathname. If directory does not start with a slash ( '/' ),
632 the contents of HOME shall be prefixed to it. The default shall
633 be nofolder. If folder is unset or set to null, user-specified
634 filenames beginning with '+' shall refer to files in the current
635 directory that begin with the literal '+' character. See also
636 outfolder below. The folder value need not affect the process‐
637 ing of the files named in MBOX and DEAD .
638 header Enable writing of the header summary when entering mailx in
640 Receive Mode. The default shall be header.
641 hold Preserve all messages that are read in the system mailbox
643 instead of putting them in the mbox save file. The default shall
644 be nohold.
645 ignore Ignore interrupts while entering messages. The default shall be
647 noignore.
648 ignoreeof
650 Ignore normal end-of-file during message input. Input can be
651 terminated only by entering a period ( '.' ) on a line by itself
652 or by the ~. command escape. The default shall be noignoreeof.
653 See also dot above.
654 indentprefix=string
656 A string that shall be added as a prefix to each line that is
658 inserted into the message by the ~m command escape. This vari‐
659 able shall default to one <tab>.
660 keep When a system mailbox, secondary mailbox, or mbox is empty,
662 truncate it to zero length instead of removing it. The default
663 shall be nokeep.
664 keepsave
666 Keep the messages that have been saved from the system mailbox
667 into other files in the file designated by the variable MBOX ,
668 instead of deleting them. The default shall be nokeepsave.
669 metoo Suppress the deletion of the login name of the user from the
671 recipient list when replying to a message or sending to a group.
672 The default shall be nometoo.
673 onehop When responding to a message that was originally sent to several
675 recipients, the other recipient addresses are normally forced to
676 be relative to the originating author's machine for the
677 response. This flag disables alteration of the recipients'
678 addresses, improving efficiency in a network where all machines
679 can send directly to all other machines (that is, one hop away).
680 The default shall be noonehop.
681 outfolder
683 Cause the files used to record outgoing messages to be located
684 in the directory specified by the folder variable unless the
685 pathname is absolute. The default shall be nooutfolder. See the
686 record variable.
687 page Insert a <form-feed> after each message sent through the pipe
689 created by the pipe command. The default shall be nopage.
690 prompt=string
692 Set the command-mode prompt to string. If string is null or if
694 noprompt is set, no prompting shall occur. The default shall be
695 to prompt with the string "? " .
696 quiet Refrain from writing the opening message and version when enter‐
698 ing mailx. The default shall be noquiet.
699 record=file
701 Record all outgoing mail in the file with the pathname file.
702 The default shall be norecord. See also outfolder above.
703 save Enable saving of messages in the dead-letter file on interrupt
705 or delivery error. See the variable DEAD for the location of the
706 dead-letter file. The default shall be save.
707 screen=number
709 Set the number of lines in a screenful of headers for the head‐
711 ers and z commands. If screen is not specified, a value based on
712 the terminal type identified by the TERM environment variable,
713 the window size, the baud rate, or some combination of these
714 shall be used.
715 sendwait
717 Wait for the background mailer to finish before returning. The
718 default shall be nosendwait.
719 showto When the sender of the message was the user who is invoking
721 mailx, write the information from the To: line instead of the
722 From: line in the header summary. The default shall be noshowto.
723 sign=string
725 Set the variable inserted into the text of a message when the ~a
726 command escape is given. The default shall be nosign. The char‐
727 acter sequences '\t' and '\n' shall be recognized in the vari‐
728 able as <tab>s and <newline>s, respectively. (See also ~i in
729 Command Escapes in mailx .)
730 Sign=string
732 Set the variable inserted into the text of a message when the ~A
733 command escape is given. The default shall be noSign. The char‐
734 acter sequences '\t' and '\n' shall be recognized in the vari‐
735 able as <tab>s and <newline>s, respectively.
736 toplines=number
738 Set the number of lines of the message to write with the top
740 command. The default shall be 5.
741 Commands in mailx
744 The following mailx commands shall be provided. In the following list,
745 header refers to lines from the message header, as shown in the OUTPUT
746 FILES section. Header-line refers to lines within the header that begin
747 with one or more non-white-space characters, immediately followed by a
748 colon and white space and continuing until the next line beginning with
749 a non-white-space character or an empty line. Header-field refers to
750 the portion of a header line prior to the first colon in that line.
751 For each of the commands listed below, the command can be entered as
753 the abbreviation (those characters in the Synopsis command word preced‐
754 ing the '[' ), the full command (all characters shown for the command
755 word, omitting the '[' and ']' ), or any truncation of the full command
756 down to the abbreviation. For example, the exit command (shown as
757 ex[it] in the Synopsis) can be entered as ex, exi, or exit.
758 The arguments to commands can be quoted, using the following methods:
760 * An argument can be enclosed between paired double-quotes ( "" ) or
762 single-quotes ( '' ); any white space, shell word expansion, or
763 backslash characters within the quotes shall be treated literally as
764 part of the argument. A double-quote shall be treated literally
765 within single-quotes and vice versa. These special properties of
766 the quote marks shall occur only when they are paired at the begin‐
767 ning and end of the argument.
768 * A backslash outside of the enclosing quotes shall be discarded and
770 the following character treated literally as part of the argument.
771 * An unquoted backslash at the end of a command line shall be dis‐
773 carded and the next line shall continue the command.
774 Filenames, where expected, shall be subjected to the following trans‐
776 formations, in sequence:
777 * If the filename begins with an unquoted plus sign, and the folder
779 variable is defined (see the folder variable), the plus sign shall
780 be replaced by the value of the folder variable followed by a slash.
781 If the folder variable is unset or is set to null, the filename
782 shall be unchanged.
783 * Shell word expansions shall be applied to the filename (see Word
785 Expansions ). If more than a single pathname results from this
786 expansion and the command is expecting one file, the effects are
787 unspecified.
788 Declare Aliases
790 Synopsis:
791 a[lias] [alias [address...]]g[roup] [alias [address...]]
794 Add the given addresses to the alias specified by alias. The names
797 shall be substituted when alias is used as a recipient address speci‐
798 fied by the user in an outgoing message (that is, other recipients
799 addressed indirectly through the reply command shall not be substituted
800 in this manner). Mail address alias substitution shall apply only when
801 the alias string is used as a full address; for example, when hlj is an
802 alias, hlj@posix.com does not trigger the alias substitution. If no
803 arguments are given, write a listing of the current aliases to standard
804 output. If only an alias argument is given, write a listing of the
805 specified alias to standard output. These listings need not reflect the
806 same order of addresses that were entered.
807 Declare Alternatives
809 Synopsis:
810 alt[ernates] name...
813 (See also the metoo command.) Declare a list of alternative names for
816 the user's login. When responding to a message, these names shall be
817 removed from the list of recipients for the response. The comparison
818 of names shall be in a case-insensitive manner. With no arguments,
819 alternates shall write the current list of alternative names.
820 Change Current Directory
822 Synopsis:
823 cd [directory]ch[dir] [directory]
826 Change directory. If directory is not specified, the contents of HOME
829 shall be used.
830 Copy Messages
832 Synopsis:
833 c[opy] [file]c[opy] [msglist] fileC[opy] [msglist]
836 Copy messages to the file named by the pathname file without marking
839 the messages as saved. Otherwise, it shall be equivalent to the save
840 command.
841 In the capitalized form, save the specified messages in a file whose
843 name is derived from the author of the message to be saved, without
844 marking the messages as saved. Otherwise, it shall be equivalent to the
845 Save command.
846 Delete Messages
848 Synopsis:
849 d[elete] [msglist]
852 Mark messages for deletion from the mailbox. The deletions shall not
855 occur until mailx quits (see the quit command) or changes mailboxes
856 (see the folder command). If autoprint is set and there are messages
857 remaining after the delete command, the current message shall be writ‐
858 ten as described for the print command (see the print command); other‐
859 wise, the mailx prompt shall be written.
860 Discard Header Fields
862 Synopsis:
863 di[scard] [header-field...]ig[nore] [header-field...]
866 Suppress the specified header fields when writing messages. Specified
869 header-fields shall be added to the list of suppressed header fields.
870 Examples of header fields to ignore are status and cc. The fields shall
871 be included when the message is saved. The Print and Type commands
872 shall override this command. The comparison of header fields shall be
873 in a case-insensitive manner. If no arguments are specified, write a
874 list of the currently suppressed header fields to standard output; the
875 listing need not reflect the same order of header fields that were
876 entered.
877 If both retain and discard commands are given, discard commands shall
879 be ignored.
880 Delete Messages and Display
882 Synopsis:
883 dp [msglist]dt [msglist]
886 Delete the specified messages as described for the delete command,
889 except that the autoprint variable shall have no effect, and the cur‐
890 rent message shall be written only if it was set to a message after the
891 last message deleted by the command. Otherwise, an informational mes‐
892 sage to the effect that there are no further messages in the mailbox
893 shall be written, followed by the mailx prompt.
894 Echo a String
896 Synopsis:
897 ec[ho] string ...
900 Echo the given strings, equivalent to the shell echo utility.
903 Edit Messages
905 Synopsis:
906 e[dit] [msglist]
909 Edit the given messages. The messages shall be placed in a temporary
912 file and the utility named by the EDITOR variable is invoked to edit
913 each file in sequence. The default EDITOR is unspecified.
914 The edit command does not modify the contents of those messages in the
916 mailbox.
917 Exit
919 Synopsis:
920 ex[it]x[it]
923 Exit from mailx without changing the mailbox. No messages shall be
926 saved in the mbox (see also quit).
927 Change Folder
929 Synopsis:
930 fi[le] [file]fold[er] [file]
933 Quit (see the quit command) from the current file of messages and read
936 in the file named by the pathname file. If no argument is given, the
937 name and status of the current mailbox shall be written.
938 Several unquoted special characters shall be recognized when used as
940 file names, with the following substitutions:
941 % The system mailbox for the invoking user.
943 %user The system mailbox for user.
945 # The previous file.
947 & The current mbox.
949 +file The named file in the folder directory. (See the folder vari‐
951 able.)
952 The default file shall be the current mailbox.
955 Display List of Folders
957 Synopsis:
958 folders
961 Write the names of the files in the directory set by the folder vari‐
964 able. The command specified by the LISTER environment variable shall be
965 used (see the ENVIRONMENT VARIABLES section).
966 Follow Up Specified Messages
968 Synopsis:
969 fo[llowup] [message]F[ollowup] [msglist]
972 In the lowercase form, respond to a message, recording the response in
975 a file whose name is derived from the author of the message. See also
976 the save and copy commands and outfolder.
977 In the capitalized form, respond to the first message in the msglist,
979 sending the message to the author of each message in the msglist. The
980 subject line shall be taken from the first message and the response
981 shall be recorded in a file whose name is derived from the author of
982 the first message. See also the Save and Copy commands and outfolder.
983 Both forms shall override the record variable, if set.
985 Display Header Summary for Specified Messages
987 Synopsis:
988 f[rom] [msglist]
991 Write the header summary for the specified messages.
994 Display Header Summary
996 Synopsis:
997 h[eaders] [message]
1000 Write the page of headers that includes the message specified. If the
1003 message argument is not specified, the current message shall not
1004 change. However, if the message argument is specified, the current mes‐
1005 sage shall become the message that appears at the top of the page of
1006 headers that includes the message specified. The screen variable sets
1007 the number of headers per page. See also the z command.
1008 Help
1010 Synopsis:
1011 hel[p]?
1014 Write a summary of commands.
1017 Hold Messages
1019 Synopsis:
1020 ho[ld] [msglist]pre[serve] [msglist]
1023 Mark the messages in msglist to be retained in the mailbox when mailx
1026 terminates. This shall override any commands that might previously have
1027 marked the messages to be deleted. During the current invocation of
1028 mailx, only the delete, dp, or dt commands shall remove the preserve
1029 marking of a message.
1030 Execute Commands Conditionally
1032 Synopsis:
1033 i[f] s|r
1036 mail-commands
1037 el[se]
1038 mail-commands
1039 en[dif]
1040 Execute commands conditionally, where if s executes the following mail-
1043 commands, up to an else or endif, if the program is in Send Mode, and
1044 if r shall cause the mail-commands to be executed only in Receive Mode.
1045 List Available Commands
1047 Synopsis:
1048 l[ist]
1051 Write a list of all commands available. No explanation shall be given.
1054 Mail a Message
1056 Synopsis:
1057 m[ail] address...
1060 Mail a message to the specified addresses or aliases.
1063 Direct Messages to mbox
1065 Synopsis:
1066 mb[ox] [msglist]
1069 Arrange for the given messages to end up in the mbox save file when
1072 mailx terminates normally. See MBOX . See also the exit and quit com‐
1073 mands.
1074 Process Next Specified Message
1076 Synopsis:
1077 n[ext] [message]
1080 If the current message has not been written (for example, by the print
1083 command) since mailx started or since any other message was the current
1084 message, behave as if the print command was entered. Otherwise, if
1085 there is an undeleted message after the current message, make it the
1086 current message and behave as if the print command was entered. Other‐
1087 wise, an informational message to the effect that there are no further
1088 messages in the mailbox shall be written, followed by the mailx prompt.
1089 Pipe Message
1091 Synopsis:
1092 pi[pe] [[msglist] command]| [[msglist] command]
1095 Pipe the messages through the given command by invoking the command
1098 interpreter specified by SHELL with two arguments: -c and command. (See
1099 also sh -c.) The application shall ensure that the command is given as
1100 a single argument. Quoting, described previously, can be used to accom‐
1101 plish this. If no arguments are given, the current message shall be
1102 piped through the command specified by the value of the cmd variable.
1103 If the page variable is set, a <form-feed> shall be inserted after each
1104 message.
1105 Display Message with Headers
1107 Synopsis:
1108 P[rint] [msglist]T[ype] [msglist]
1111 Write the specified messages, including all header lines, to standard
1114 output. Override suppression of lines by the discard, ignore, and
1115 retain commands. If crt is set, the messages longer than the number of
1116 lines specified by the crt variable shall be paged through the command
1117 specified by the PAGER environment variable.
1118 Display Message
1120 Synopsis:
1121 p[rint] [msglist]t[ype] [msglist]
1124 Write the specified messages to standard output. If crt is set, the
1127 messages longer than the number of lines specified by the crt variable
1128 shall be paged through the command specified by the PAGER environment
1129 variable.
1130 Quit
1132 Synopsis:
1133 q[uit]
1136 end-of-file
1137 Terminate mailx, storing messages that were read in mbox (if the cur‐
1140 rent mailbox is the system mailbox and unless hold is set), deleting
1141 messages that have been explicitly saved (unless keepsave is set), dis‐
1142 carding messages that have been deleted, and saving all remaining mes‐
1143 sages in the mailbox.
1144 Reply to a Message List
1146 Synopsis:
1147 R[eply] [msglist]R[espond] [msglist]
1150 Mail a reply message to the sender of each message in the msglist. The
1153 subject line shall be formed by concatenating Re: <space> (unless it
1154 already begins with that string) and the subject from the first mes‐
1155 sage. If record is set to a filename, the response shall be saved at
1156 the end of that file.
1157 See also the flipr variable.
1159 Reply to a Message
1161 Synopsis:
1162 r[eply] [message]r[espond] [message]
1165 Mail a reply message to all recipients included in the header of the
1168 message. The subject line shall be formed by concatenating Re: <space>
1169 (unless it already begins with that string) and the subject from the
1170 message. If record is set to a filename, the response shall be saved at
1171 the end of that file.
1172 See also the flipr variable.
1174 Retain Header Fields
1176 Synopsis:
1177 ret[ain] [header-field...]
1180 Retain the specified header fields when writing messages. This command
1183 shall override all discard and ignore commands. The comparison of
1184 header fields shall be in a case-insensitive manner. If no arguments
1185 are specified, write a list of the currently retained header fields to
1186 standard output; the listing need not reflect the same order of header
1187 fields that were entered.
1188 Save Messages
1190 Synopsis:
1191 s[ave] [file]s[ave] [msglist] fileS[ave] [msglist]
1194 Save the specified messages in the file named by the pathname file, or
1197 the mbox if the file argument is omitted. The file shall be created if
1198 it does not exist; otherwise, the messages shall be appended to the
1199 file. The message shall be put in the state saved, and shall behave as
1200 specified in the description of the saved state when the current mail‐
1201 box is exited by the quit or file command.
1202 In the capitalized form, save the specified messages in a file whose
1204 name is derived from the author of the first message. The name of the
1205 file shall be taken to be the author's name with all network addressing
1206 stripped off. See also the Copy, followup, and Followup commands and
1207 outfolder variable.
1208 Set Variables
1210 Synopsis:
1211 se[t] [name[=[string]] ...] [name=number ...] [noname ...]
1214 Define one or more variables called name. The variable can be given a
1217 null, string, or numeric value. Quoting and backslash escapes can occur
1218 anywhere in string, as described previously, as if the string portion
1219 of the argument were the entire argument. The forms name and name=
1220 shall be equivalent to name="" for variables that take string values.
1221 The set command without arguments shall write a list of all defined
1222 variables and their values. The no name form shall be equivalent to
1223 unset name.
1224 Invoke a Shell
1226 Synopsis:
1227 sh[ell]
1230 Invoke an interactive command interpreter (see also SHELL ).
1233 Display Message Size
1235 Synopsis:
1236 si[ze] [msglist]
1239 Write the size in bytes of each of the specified messages.
1242 Read mailx Commands From a File
1244 Synopsis:
1245 so[urce] file
1248 Read and execute commands from the file named by the pathname file and
1251 return to command mode.
1252 Display Beginning of Messages
1254 Synopsis:
1255 to[p] [msglist]
1258 Write the top few lines of each of the specified messages. If the
1261 toplines variable is set, it is taken as the number of lines to write.
1262 The default shall be 5.
1263 Touch Messages
1265 Synopsis:
1266 tou[ch] [msglist]
1269 Touch the specified messages. If any message in msglist is not specifi‐
1272 cally deleted nor saved in a file, it shall be placed in the mbox upon
1273 normal termination. See exit and quit.
1274 Delete Aliases
1276 Synopsis:
1277 una[lias] [alias]...
1280 Delete the specified alias names. If a specified alias does not exist,
1283 the results are unspecified.
1284 Undelete Messages
1286 Synopsis:
1287 u[ndelete] [msglist]
1290 Change the state of the specified messages from deleted to read. If
1293 autoprint is set, the last message of those restored shall be written.
1294 If msglist is not specified, the message shall be selected as follows:
1295 * If there are any deleted messages that follow the current message,
1297 the first of these shall be chosen.
1298 * Otherwise, the last deleted message that also precedes the current
1300 message shall be chosen.
1301 Unset Variables
1303 Synopsis:
1304 uns[et] name...
1307 Cause the specified variables to be erased.
1310 Edit Message with Full-Screen Editor
1312 Synopsis:
1313 v[isual] [msglist]
1316 Edit the given messages with a screen editor. Each message shall be
1319 placed in a temporary file, and the utility named by the VISUAL vari‐
1320 able shall be invoked to edit each file in sequence. The default edi‐
1321 tor shall be vi.
1322 The visual command does not modify the contents of those messages in
1324 the mailbox.
1325 Write Messages to a File
1327 Synopsis:
1328 w[rite] [msglist] file
1331 Write the given messages to the file specified by the pathname file,
1334 minus the message header. Otherwise, it shall be equivalent to the save
1335 command.
1336 Scroll Header Display
1338 Synopsis:
1339 z[+|-]
1342 Scroll the header display forward (if '+' is specified or if no option
1345 is specified) or backward (if '-' is specified) one screenful. The num‐
1346 ber of headers written shall be set by the screen variable.
1347 Invoke Shell Command
1349 Synopsis:
1350 !command
1353 Invoke the command interpreter specified by SHELL with two arguments:
1356 -c and command. (See also sh -c.) If the bang variable is set, each
1357 unescaped occurrence of '!' in command shall be replaced with the com‐
1358 mand executed by the previous ! command or ~! command escape.
1359 Null Command
1361 Synopsis:
1362 # comment
1365 This null command (comment) shall be ignored by mailx.
1368 Display Current Message Number
1370 Synopsis:
1371 =
1374 Write the current message number.
1377 Command Escapes in mailx
1379 The following commands can be entered only from input mode, by begin‐
1380 ning a line with the escape character (by default, tilde ( '~' )). See
1381 the escape variable description for changing this special character.
1382 The format for the commands shall be:
1383 <escape-character><command-char><separator>[<arguments>]
1386 where the <separator> can be zero or more <blank>s.
1388 In the following descriptions, the application shall ensure that the
1390 argument command (but not mailx-command) is a shell command string. Any
1391 string acceptable to the command interpreter specified by the SHELL
1392 variable when it is invoked as SHELL -c command_string shall be valid.
1393 The command can be presented as multiple arguments (that is, quoting is
1394 not required).
1395 Command escapes that are listed with msglist or mailx-command arguments
1397 are invalid in Send Mode and produce unspecified results.
1398 ~! command
1400 Invoke the command interpreter specified by SHELL with two argu‐
1401 ments: -c and command; and then return to input mode. If the
1402 bang variable is set, each unescaped occurrence of '!' in com‐
1403 mand shall be replaced with the command executed by the previous
1404 ! command or ~! command escape.
1405 ~. Simulate end-of-file (terminate message input).
1407 ~: mailx-command, ~_ mailx-command
1409 Perform the command-level request.
1411 ~? Write a summary of command escapes.
1413 ~A This shall be equivalent to ~i Sign.
1415 ~a This shall be equivalent to ~i sign.
1417 ~b name...
1419 Add the names to the blind carbon copy ( Bcc) list.
1420 ~c name...
1422 Add the names to the carbon copy ( Cc) list.
1423 ~d Read in the dead-letter file. See DEAD for a description of this
1425 file.
1426 ~e Invoke the editor, as specified by the EDITOR environment vari‐
1428 able, on the partial message.
1429 ~f [msglist]
1431 Forward the specified messages. The specified messages shall be
1432 inserted into the current message without alteration. This com‐
1433 mand escape also shall insert message headers into the message
1434 with field selection affected by the discard, ignore, and retain
1435 commands.
1436 ~F [msglist]
1438 This shall be the equivalent of the ~f command escape, except
1439 that all headers shall be included in the message, regardless of
1440 previous discard, ignore, and retain commands.
1441 ~h If standard input is a terminal, prompt for a Subject line and
1443 the To, Cc, and Bcc lists. Other implementation-defined headers
1444 may also be presented for editing. If the field is written with
1445 an initial value, it can be edited as if it had just been typed.
1446 ~i string
1448 Insert the value of the named variable, followed by a <newline>,
1449 into the text of the message. If the string is unset or null,
1450 the message shall not be changed.
1451 ~m [msglist]
1453 Insert the specified messages into the message, prefixing non-
1454 empty lines with the string in the indentprefix variable. This
1455 command escape also shall insert message headers into the mes‐
1456 sage, with field selection affected by the discard, ignore, and
1457 retain commands.
1458 ~M [msglist]
1460 This shall be the equivalent of the ~m command escape, except
1461 that all headers shall be included in the message, regardless of
1462 previous discard, ignore, and retain commands.
1463 ~p Write the message being entered. If the message is longer than
1465 crt lines (see Internal Variables in mailx ), the output shall
1466 be paginated as described for the PAGER variable.
1467 ~q Quit (see the quit command) from input mode by simulating an
1469 interrupt. If the body of the message is not empty, the partial
1470 message shall be saved in the dead-letter file. See DEAD for a
1471 description of this file.
1472 ~r file, ~<
1474 file, ~r !command, ~< !command
1475 Read in the file specified by the pathname file. If the argument
1477 begins with an exclamation mark ( '!' ), the rest of the string
1478 shall be taken as an arbitrary system command; the command
1479 interpreter specified by SHELL shall be invoked with two argu‐
1480 ments: -c and command. The standard output of command shall be
1481 inserted into the message.
1482 ~s string
1484 Set the subject line to string.
1485 ~t name...
1487 Add the given names to the To list.
1488 ~v Invoke the full-screen editor, as specified by the VISUAL envi‐
1490 ronment variable, on the partial message.
1491 ~w file
1493 Write the partial message, without the header, onto the file
1494 named by the pathname file. The file shall be created or the
1495 message shall be appended to it if the file exists.
1496 ~x Exit as with ~q, except the message shall not be saved in the
1498 dead-letter file.
1499 ~| command
1501 Pipe the body of the message through the given command by invok‐
1502 ing the command interpreter specified by SHELL with two argu‐
1503 ments: -c and command. If the command returns a successful exit
1504 status, the standard output of the command shall replace the
1505 message. Otherwise, the message shall remain unchanged. If the
1506 command fails, an error message giving the exit status shall be
1507 written.
1508
1511 When the -e option is specified, the following exit values are
1512 returned:
1513 0 Mail was found.
1515 >0 Mail was not found or an error occurred.
1517 Otherwise, the following exit values are returned:
1520 0 Successful completion; note that this status implies that all
1522 messages were sent, but it gives no assurances that any of them
1523 were actually delivered.
1524 >0 An error occurred.
1526
1529 When in input mode (Receive Mode) or Send Mode:
1530 * If an error is encountered processing a command escape (see Command
1532 Escapes in mailx ), a diagnostic message shall be written to stan‐
1533 dard error, and the message being composed may be modified, but this
1534 condition shall not prevent the message from being sent.
1535 * Other errors shall prevent the sending of the message.
1537 When in command mode:
1539 * Default.
1541 The following sections are informative.
1543
1545 Delivery of messages to remote systems requires the existence of commu‐
1546 nication paths to such systems. These need not exist.
1547 Input lines are limited to {LINE_MAX} bytes, but mailers between sys‐
1549 tems may impose more severe line-length restrictions. This volume of
1550 IEEE Std 1003.1-2001 does not place any restrictions on the length of
1551 messages handled by mailx, and for delivery of local messages the only
1552 limitations should be the normal problems of available disk space for
1553 the target mail file. When sending messages to external machines,
1554 applications are advised to limit messages to less than 100000 bytes
1555 because some mail gateways impose message-length restrictions.
1556 The format of the system mailbox is intentionally unspecified. Not all
1558 systems implement system mailboxes as flat files, particularly with the
1559 advent of multimedia mail messages. Some system mailboxes may be multi‐
1560 ple files, others records in a database. The internal format of the
1561 messages themselves is specified with the historical format from Ver‐
1562 sion 7, but only after the messages have been saved in some file other
1563 than the system mailbox. This was done so that many historical applica‐
1564 tions expecting text-file mailboxes are not broken.
1565 Some new formats for messages can be expected in the future, probably
1567 including binary data, bit maps, and various multimedia objects. As
1568 described here, mailx is not prohibited from handling such messages,
1569 but it must store them as text files in secondary mailboxes (unless
1570 some extension, such as a variable or command line option, is used to
1571 change the stored format). Its method of doing so is implementation-
1572 defined and might include translating the data into text file-compati‐
1573 ble or readable form or omitting certain portions of the message from
1574 the stored output.
1575 The discard and ignore commands are not inverses of the retain command.
1577 The retain command discards all header-fields except those explicitly
1578 retained. The discard command keeps all header-fields except those
1579 explicitly discarded. If headers exist on the retained header list,
1580 discard and ignore commands are ignored.
1581
1583 None.
1584
1586 The standard developers felt strongly that a method for applications to
1587 send messages to specific users was necessary. The obvious example is a
1588 batch utility, running non-interactively, that wishes to communicate
1589 errors or results to a user. However, the actual format, delivery mech‐
1590 anism, and method of reading the message are clearly beyond the scope
1591 of this volume of IEEE Std 1003.1-2001.
1592 The intent of this command is to provide a simple, portable interface
1594 for sending messages non-interactively. It merely defines a "front-end"
1595 to the historical mail system. It is suggested that implementations
1596 explicitly denote the sender and recipient in the body of the delivered
1597 message. Further specification of formats for either the message enve‐
1598 lope or the message itself were deliberately not made, as the industry
1599 is in the midst of changing from the current standards to a more inter‐
1600 nationalized standard and it is probably incorrect, at this time, to
1601 require either one.
1602 Implementations are encouraged to conform to the various delivery mech‐
1604 anisms described in the CCITT X.400 standards or to the equivalent
1605 Internet standards, described in Internet Request for Comment (RFC)
1606 documents RFC 819, RFC 822, RFC 920, RFC 921, and RFC 1123.
1607 Many historical systems modified each body line that started with From
1609 by prefixing the 'F' with '>' . It is unnecessary, but allowed, to do
1610 that when the string does not follow a blank line because it cannot be
1611 confused with the next header.
1612 The edit and visual commands merely edit the specified messages in a
1614 temporary file. They do not modify the contents of those messages in
1615 the mailbox; such a capability could be added as an extension, such as
1616 by using different command names.
1617 The restriction on a subject line being {LINE_MAX}-10 bytes is based on
1619 the historical format that consumes 10 bytes for Subject: and the
1620 trailing <newline>. Many historical mailers that a message may
1621 encounter on other systems are not able to handle lines that long, how‐
1622 ever.
1623 Like the utilities logger and lp, mailx admittedly is difficult to
1625 test. This was not deemed sufficient justification to exclude this
1626 utility from this volume of IEEE Std 1003.1-2001. It is also arguable
1627 that it is, in fact, testable, but that the tests themselves are not
1628 portable.
1629 When mailx is being used by an application that wishes to receive the
1631 results as if none of the User Portability Utilities option features
1632 were supported, the DEAD environment variable must be set to /dev/null.
1633 Otherwise, it may be subject to the file creations described in mailx
1634 ASYNCHRONOUS EVENTS. Similarly, if the MAILRC environment variable is
1635 not set to /dev/null, historical versions of mailx and Mail read ini‐
1636 tialization commands from a file before processing begins. Since the
1637 initialization that a user specifies could alter the contents of mes‐
1638 sages an application is trying to send, such applications must set
1639 MAILRC to /dev/null.
1640 The description of LC_TIME uses "may affect" because many historical
1642 implementations do not or cannot manipulate the date and time strings
1643 in the incoming mail headers. Some headers found in incoming mail do
1644 not have enough information to determine the timezone in which the mail
1645 originated, and, therefore, mailx cannot convert the date and time
1646 strings into the internal form that then is parsed by routines like
1647 strftime() that can take LC_TIME settings into account. Changing all
1648 these times to a user-specified format is allowed, but not required.
1649 The paginator selected when PAGER is null or unset is partially unspec‐
1651 ified to allow the System V historical practice of using pg as the
1652 default. Bypassing the pagination function, such as by declaring that
1653 cat is the paginator, would not meet with the intended meaning of this
1654 description. However, any "portable user" would have to set PAGER
1655 explicitly to get his or her preferred paginator on all systems. The
1656 paginator choice was made partially unspecified, unlike the VISUAL edi‐
1657 tor choice (mandated to be vi) because most historical pagers follow a
1658 common theme of user input, whereas editors differ dramatically.
1659 Options to specify addresses as cc (carbon copy) or bcc (blind carbon
1661 copy) were considered to be format details and were omitted.
1662 A zero exit status implies that all messages were sent, but it gives no
1664 assurances that any of them were actually delivered. The reliability of
1665 the delivery mechanism is unspecified and is an appropriate marketing
1666 distinction between systems.
1667 In order to conform to the Utility Syntax Guidelines, a solution was
1669 required to the optional file option-argument to -f. By making file an
1670 operand, the guidelines are satisfied and users remain portable. How‐
1671 ever, it does force implementations to support usage such as:
1672 mailx -fin mymail.box
1675 The no name method of unsetting variables is not present in all histor‐
1677 ical systems, but it is in System V and provides a logical set of com‐
1678 mands corresponding to the format of the display of options from the
1679 mailx set command without arguments.
1680 The ask and asksub variables are the names selected by BSD and System
1682 V, respectively, for the same feature. They are synonyms in this volume
1683 of IEEE Std 1003.1-2001.
1684 The mailx echo command was not documented in the BSD version and has
1686 been omitted here because it is not obviously useful for interactive
1687 users.
1688 The default prompt on the System V mailx is a question mark, on BSD
1690 Mail an ampersand. Since this volume of IEEE Std 1003.1-2001 chose the
1691 mailx name, it kept the System V default, assuming that BSD users would
1692 not have difficulty with this minor incompatibility (that they can
1693 override).
1694 The meanings of r and R are reversed between System V mailx and SunOS
1696 Mail. Once again, since this volume of IEEE Std 1003.1-2001 chose the
1697 mailx name, it kept the System V default, but allows the SunOS user to
1698 achieve the desired results using flipr, an internal variable in System
1699 V mailx, although it has not been documented in the SVID.
1700 The indentprefix variable, the retain and unalias commands, and the ~F
1702 and ~M command escapes were adopted from 4.3 BSD Mail.
1703 The version command was not included because no sufficiently general
1705 specification of the version information could be devised that would
1706 still be useful to a portable user. This command name should be used by
1707 suppliers who wish to provide version information about the mailx com‐
1708 mand.
1709 The "implementation-specific (unspecified) system start-up file" his‐
1711 torically has been named /etc/mailx.rc, but this specific name and
1712 location are not required.
1713 The intent of the wording for the next command is that if any command
1715 has already displayed the current message it should display a following
1716 message, but, otherwise, it should display the current message. Con‐
1717 sider the command sequence:
1718 next 3
1721 delete 3
1722 next
1723 where the autoprint option was not set. The normative text specifies
1725 that the second next command should display a message following the
1726 third message, because even though the current message has not been
1727 displayed since it was set by the delete command, it has been displayed
1728 since the current message was anything other than message number 3.
1729 This does not always match historical practice in some implementations,
1730 where the command file address followed by next (or the default com‐
1731 mand) would skip the message for which the user had searched.
1732
1734 None.
1735
1737 Shell Command Language , ed , ls , more , vi
1738
1740 Portions of this text are reprinted and reproduced in electronic form
1741 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
1742 -- Portable Operating System Interface (POSIX), The Open Group Base
1743 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
1744 Electrical and Electronics Engineers, Inc and The Open Group. In the
1745 event of any discrepancy between this version and the original IEEE and
1746 The Open Group Standard, the original IEEE and The Open Group Standard
1747 is the referee document. The original Standard can be obtained online
1748 at http://www.opengroup.org/unix/online.html .
1749IEEE/The Open Group 2003 MAILX(P)