The entire EXTENDED DESCRIPTION section shall apply only to implementations supporting the User Portability Utilities
option.
The mailx utility cannot guarantee support for all character encodings in all circumstances. For example, inter-system
mail may be restricted to 7-bit data by the underlying network, 8-bit data need not be portable to non-internationalized systems,
and so on. Under these circumstances, it is recommended that only characters defined in the ISO/IEC 646:1991 standard
International Reference Version (equivalent to ASCII) 7-bit range of characters be used.
When mailx is invoked using one of the Receive Mode synopsis forms, it shall write a page of header-summary lines (if
-N was not specified and there are messages, see below), followed by a prompt indicating that mailx can accept
regular commands (see Commands in mailx ); this is termed command mode. The page of
header-summary lines shall contain the first new message if there are new messages, or the first unread message if there are unread
messages, or the first message. When mailx is invoked using the Send Mode synopsis and standard input is a terminal, if no
subject is specified on the command line and the asksub variable is set, a prompt for the subject shall be written. At this
point, mailx shall be in input mode. This input mode shall also be entered when using one of the Receive Mode synopsis forms
and a reply or new message is composed using the reply, Reply, followup, Followup, or mail
commands and standard input is a terminal. When the message is typed and the end of the message is encountered, the message shall
be passed to the mail delivery software. Commands can be entered by beginning a line with the escape character (by default, tilde (
'˜' )) followed by a single command letter and optional arguments. See Commands in
mailx for a summary of these commands. It is unspecified what effect these commands will have if standard input is not a
terminal when a message is entered using either the Send Mode synopsis, or the Read Mode commands reply, Reply,
followup, Followup, or mail.
- Note:
- For notational convenience, this section uses the default escape character, tilde, in all references and examples.
At any time, the behavior of mailx shall be governed by a set of environmental and internal variables. These are flags
and valued parameters that can be set and cleared via the mailx set and unset commands.
Regular commands are of the form:
[command] [msglist] [argument ...]
If no command is specified in command mode, next shall be assumed. In input mode, commands shall be recognized by
the escape character, and lines not treated as commands shall be taken as input for the message.
In command mode, each message shall be assigned a sequential number, starting with 1.
All messages have a state that shall affect how they are displayed in the header summary and how they are retained or deleted
upon termination of mailx. There is at any time the notion of a current message, which shall be marked by a
'>' at the beginning of a line in the header summary. When mailx is invoked using one of the Receive Mode
synopsis forms, the current message shall be the first new message, if there is a new message, or the first unread message if there
is an unread message, or the first message if there are any messages, or unspecified if there are no messages in the mailbox. Each
command that takes an optional list of messages (msglist) or an optional single message (message) on which to operate
shall leave the current message set to the highest-numbered message of the messages specified, unless the command deletes messages,
in which case the current message shall be set to the first undeleted message (that is, a message not in the deleted state) after
the highest-numbered message deleted by the command, if one exists, or the first undeleted message before the highest-numbered
message deleted by the command, if one exists, or to an unspecified value if there are no remaining undeleted messages. All
messages shall be in one of the following states:
- new
- The message is present in the system mailbox and has not been viewed by the user or moved to any other state. Messages in state
new when mailx quits shall be retained in the system mailbox.
- unread
- The message has been present in the system mailbox for more than one invocation of mailx and has not been viewed by the
user or moved to any other state. Messages in state unread when mailx quits shall be retained in the system
mailbox.
- read
- The message has been processed by one of the following commands: ˜f, ˜m, ˜F,
˜M, copy, mbox, next, pipe, print, Print, top, type,
Type, undelete. The delete, dp, and dt commands may also cause the next message to be marked as
read, depending on the value of the autoprint variable. Messages that are in the system mailbox and in state
read when mailx quits shall be saved in the mbox, unless the internal variable hold was set. Messages
that are in the mbox or in a secondary mailbox and in state read when mailx quits shall be retained in their
current location.
- deleted
- The message has been processed by one of the following commands: delete, dp, dt. Messages in state
deleted when mailx quits shall be deleted. Deleted messages shall be ignored until mailx quits or changes
mailboxes or they are specified to the undelete command; for example, the message specification / string shall only search
the subject lines of messages that have not yet been deleted, unless the command operating on the list of messages is
undelete. No deleted message or deleted message header shall be displayed by any mailx command other than
undelete.
- preserved
- The message has been processed by a preserve command. When mailx quits, the message shall be retained in its
current location.
- saved
- The message has been processed by one of the following commands: save or write. If the current mailbox is the
system mailbox, and the internal variable keepsave is set, messages in the state saved shall be saved to the file designated
by the MBOX variable (see the ENVIRONMENT VARIABLES section). If the current mailbox is the system mailbox, messages in the
state saved shall be deleted from the current mailbox, when the quit or file command is used to exit the
current mailbox.
The header-summary line for each message shall indicate the state of the message.
Many commands take an optional list of messages ( msglist) on which to operate, which defaults to the current message. A
msglist is a list of message specifications separated by <blank>s, which can include:
- n
- Message number n.
- +
- The next undeleted message, or the next deleted message for the undelete command.
- -
- The next previous undeleted message, or the next previous deleted message for the undelete command.
- .
- The current message.
- ^
- The first undeleted message, or the first deleted message for the undelete command.
- $
- The last message.
- *
- All messages.
- n-m
- An inclusive range of message numbers.
- address
- All messages from address; any address as shown in a header summary shall be matchable in this form.
- /string
- All messages with string in the subject line (case ignored).
- :c
- All messages of type c, where c shall be one of:
- d
- Deleted messages.
- n
- New messages.
- o
- Old messages (any not in state read or new).
- r
- Read messages.
- u
- Unread messages.
Other commands take an optional message ( message) on which to operate, which defaults to the current message. All of the
forms allowed for msglist are also allowed for message, but if more than one message is specified, only the first
shall be operated on.
Other arguments are usually arbitrary strings whose usage depends on the command involved.
Start-Up in mailx
At start-up time, mailx shall take the following steps in sequence:
-
Establish all variables at their stated default values.
-
Process command line options, overriding corresponding default values.
-
Import any of the DEAD , EDITOR , MBOX , LISTER , PAGER , SHELL , or VISUAL
variables that are present in the environment, overriding the corresponding default values.
-
Read mailx commands from an unspecified system start-up file, unless the -n option is given, to initialize any
internal mailx variables and aliases.
-
Process the start-up file of mailx commands named in the user MAILRC variable.
Most regular mailx commands are valid inside start-up files, the most common use being to set up initial display options
and alias lists. The following commands shall be invalid in the start-up file: !, edit, hold, mail,
preserve, reply, Reply, shell, visual, Copy, followup, and Followup. Any
errors in the start-up file shall either cause mailx to terminate with a diagnostic message and a non-zero status or to
continue after writing a diagnostic message, ignoring the remainder of the lines in the start-up file.
A blank line in a start-up file shall be ignored.
Internal Variables in mailx
The following variables are internal mailx variables. Each internal variable can be set via the mailx set
command at any time. The unset and set no name commands can be used to erase variables.
In the following list, variables shown as:
variable
represent Boolean values. Variables shown as:
variable=value
shall be assigned string or numeric values. For string values, the rules in Commands in mailx
concerning filenames and quoting shall also apply.
The defaults specified here may be changed by the implementation-defined system start-up file unless the user specifies the
-n option.
- allnet
- All network names whose login name components match shall be treated as identical. This shall cause the msglist message
specifications to behave similarly. The default shall be noallnet. See also the alternates command and the
metoo variable.
- append
- Append messages to the end of the mbox file upon termination instead of placing them at the beginning. The default shall
be noappend. This variable shall not affect the save command when saving to mbox.
- ask, asksub
- Prompt for a subject line on outgoing mail if one is not specified on the command line with the -s option. The
ask and asksub forms are synonyms; the system shall refer to asksub and noasksub in its messages, but
shall accept ask and noask as user input to mean asksub and noasksub. It shall not be possible to set
both ask and noasksub, or noask and asksub. The default shall be asksub, but no prompting shall
be done if standard input is not a terminal.
- askbcc
- Prompt for the blind copy list. The default shall be noaskbcc.
- askcc
- Prompt for the copy list. The default shall be noaskcc.
- autoprint
- Enable automatic writing of messages after delete and undelete commands. The default shall be
noautoprint.
- bang
- Enable the special-case treatment of exclamation marks ( '!' ) in escape command lines; see the escape command
and Command Escapes in mailx . The default shall be nobang, disabling the expansion of
'!' in the command argument to the ˜! command and the ˜<! command escape.
- cmd=command
Set the default command to be invoked by the pipe command. The default shall be nocmd.- crt=number
- Pipe messages having more than number lines through the command specified by the value of the PAGER variable. The
default shall be nocrt. If it is set to null, the value used is implementation-defined.
- debug
- [XSI]
![[Option Start]](../images/opt-start.gif)
Enable verbose diagnostics for debugging. Messages are not delivered. The default shall be nodebug. ![[Option End]](../images/opt-end.gif)
- dot
- When dot is set, a period on a line by itself during message input from a terminal shall also signify end-of-file (in
addition to normal end-of-file). The default shall be nodot. If ignoreeof is set (see below), a setting of
nodot shall be ignored and the period is the only method to terminate input mode.
- escape=c
- Set the command escape character to be the character 'c' . By default, the command escape character shall be tilde. If
escape is unset, tilde shall be used; if it is set to null, command escaping shall be disabled.
- flipr
- Reverse the meanings of the R and r commands. The default shall be noflipr.
- folder=directory
The default directory for saving mail files. User-specified filenames beginning with a plus sign ( '+' ) shall be expanded
by preceding the filename with this directory name to obtain the real pathname. If directory does not start with a slash (
'/' ), the contents of HOME shall be prefixed to it. The default shall be nofolder. If folder is
unset or set to null, user-specified filenames beginning with '+' shall refer to files in the current directory that begin
with the literal '+' character. See also outfolder below. The folder value need not affect the processing of
the files named in MBOX and DEAD .- header
- Enable writing of the header summary when entering mailx in Receive Mode. The default shall be header.
- hold
- Preserve all messages that are read in the system mailbox instead of putting them in the mbox save file. The default
shall be nohold.
- ignore
- Ignore interrupts while entering messages. The default shall be noignore.
- ignoreeof
- Ignore normal end-of-file during message input. Input can be terminated only by entering a period ( '.' ) on a line by
itself or by the ˜. command escape. The default shall be noignoreeof. See also dot above.
- indentprefix=string
A string that shall be added as a prefix to each line that is inserted into the message by the ˜m command escape. This
variable shall default to one <tab>.- keep
- When a system mailbox, secondary mailbox, or mbox is empty, truncate it to zero length instead of removing it. The
default shall be nokeep.
- keepsave
- Keep the messages that have been saved from the system mailbox into other files in the file designated by the variable MBOX
, instead of deleting them. The default shall be nokeepsave.
- metoo
- Suppress the deletion of the login name of the user from the recipient list when replying to a message or sending to a group.
The default shall be nometoo.
- onehop
- [XSI]
When responding to a message that was originally sent to several recipients, the other recipient addresses are normally forced to
be relative to the originating author's machine for the response. This flag disables alteration of the recipients' addresses,
improving efficiency in a network where all machines can send directly to all other machines (that is, one hop away). The default
shall be noonehop.
- outfolder
- Cause the files used to record outgoing messages to be located in the directory specified by the folder variable unless
the pathname is absolute. The default shall be nooutfolder. See the record variable.
- page
- Insert a <form-feed> after each message sent through the pipe created by the pipe command. The default shall be
nopage.
- prompt=string
Set the command-mode prompt to string. If string is null or if noprompt is set, no prompting shall occur. The
default shall be to prompt with the string "? " .- quiet
- Refrain from writing the opening message and version when entering mailx. The default shall be noquiet.
- record=file
- Record all outgoing mail in the file with the pathname file. The default shall be norecord. See also
outfolder above.
- save
- Enable saving of messages in the dead-letter file on interrupt or delivery error. See the variable DEAD for the location
of the dead-letter file. The default shall be save.
- screen=number
Set the number of lines in a screenful of headers for the headers and z commands. If screen is not specified,
a value based on the terminal type identified by the TERM environment variable, the window size, the baud rate, or some
combination of these shall be used.- sendwait
- Wait for the background mailer to finish before returning. The default shall be nosendwait.
- showto
- When the sender of the message was the user who is invoking mailx, write the information from the To: line
instead of the From: line in the header summary. The default shall be noshowto.
- sign=string
- Set the variable inserted into the text of a message when the ˜a command escape is given. The default shall be
nosign. The character sequences '\t' and '\n' shall be recognized in the variable as <tab>s and
<newline>s, respectively. (See also ˜i in Command Escapes in mailx .)
- Sign=string
- Set the variable inserted into the text of a message when the ˜A command escape is given. The default shall be
noSign. The character sequences '\t' and '\n' shall be recognized in the variable as <tab>s and
<newline>s, respectively.
- toplines=number
Set the number of lines of the message to write with the top command. The default shall be 5.
Commands in mailx
The following mailx commands shall be provided. In the following list, header refers to lines from the message header, as
shown in the OUTPUT FILES section. Header-line refers to lines within the header that begin with one or more non-white-space
characters, immediately followed by a colon and white space and continuing until the next line beginning with a non-white-space
character or an empty line. Header-field refers to the portion of a header line prior to the first colon in that line.
For each of the commands listed below, the command can be entered as the abbreviation (those characters in the Synopsis command
word preceding the '[' ), the full command (all characters shown for the command word, omitting the '[' and
']' ), or any truncation of the full command down to the abbreviation. For example, the exit command (shown as
ex[it] in the Synopsis) can be entered as ex, exi, or exit.
The arguments to commands can be quoted, using the following methods:
-
An argument can be enclosed between paired double-quotes ( "" ) or single-quotes ( '' ); any white space,
shell word expansion, or backslash characters within the quotes shall be treated literally as part of the argument. A double-quote
shall be treated literally within single-quotes and vice versa. These special properties of the quote marks shall occur only
when they are paired at the beginning and end of the argument.
-
A backslash outside of the enclosing quotes shall be discarded and the following character treated literally as part of the
argument.
-
An unquoted backslash at the end of a command line shall be discarded and the next line shall continue the command.
Filenames, where expected, shall be subjected to the following transformations, in sequence:
-
If the filename begins with an unquoted plus sign, and the folder variable is defined (see the folder variable),
the plus sign shall be replaced by the value of the folder variable followed by a slash. If the folder variable is
unset or is set to null, the filename shall be unchanged.
-
Shell word expansions shall be applied to the filename (see Word Expansions ). If
more than a single pathname results from this expansion and the command is expecting one file, the effects are unspecified.
Declare Aliases
- Synopsis:
-
a[lias] [alias [address...]]g[roup] [alias [address...]]
Add the given addresses to the alias specified by alias. The names shall be substituted when alias is used as a
recipient address specified by the user in an outgoing message (that is, other recipients addressed indirectly through the
reply command shall not be substituted in this manner). Mail address alias substitution shall apply only when the alias
string is used as a full address; for example, when hlj is an alias, hlj@posix.com does not trigger the alias
substitution. If no arguments are given, write a listing of the current aliases to standard output. If only an alias
argument is given, write a listing of the specified alias to standard output. These listings need not reflect the same order of
addresses that were entered.
Declare Alternatives
- Synopsis:
-
alt[ernates] name...
(See also the metoo command.) Declare a list of alternative names for the user's login. When responding to a message,
these names shall be removed from the list of recipients for the response. The comparison of names shall be in a case-insensitive
manner. With no arguments, alternates shall write the current list of alternative names.
Change Current Directory
- Synopsis:
-
cd [directory]ch[dir] [directory]
Change directory. If directory is not specified, the contents of HOME shall be used.
Copy Messages
- Synopsis:
-
c[opy] [file]c[opy] [msglist] fileC[opy] [msglist]
Copy messages to the file named by the pathname file without marking the messages as saved. Otherwise, it shall be
equivalent to the save command.
In the capitalized form, save the specified messages in a file whose name is derived from the author of the message to be saved,
without marking the messages as saved. Otherwise, it shall be equivalent to the Save command.
Delete Messages
- Synopsis:
-
d[elete] [msglist]
Mark messages for deletion from the mailbox. The deletions shall not occur until mailx quits (see the quit
command) or changes mailboxes (see the folder command). If autoprint is set and there are messages remaining after
the delete command, the current message shall be written as described for the print command (see the print
command); otherwise, the mailx prompt shall be written.
Discard Header Fields
- Synopsis:
-
di[scard] [header-field...]ig[nore] [header-field...]
Suppress the specified header fields when writing messages. Specified header-fields shall be added to the list of
suppressed header fields. Examples of header fields to ignore are status and cc. The fields shall be included when
the message is saved. The Print and Type commands shall override this command. The comparison of header fields shall
be in a case-insensitive manner. If no arguments are specified, write a list of the currently suppressed header fields to standard
output; the listing need not reflect the same order of header fields that were entered.
If both retain and discard commands are given, discard commands shall be ignored.
Delete Messages and Display
- Synopsis:
-
dp [msglist]dt [msglist]
Delete the specified messages as described for the delete command, except that the autoprint variable shall have
no effect, and the current message shall be written only if it was set to a message after the last message deleted by the command.
Otherwise, an informational message to the effect that there are no further messages in the mailbox shall be written, followed by
the mailx prompt.
Echo a String
- Synopsis:
-
ec[ho] string ...
Echo the given strings, equivalent to the shell echo utility.
Edit Messages
- Synopsis:
-
e[dit] [msglist]
Edit the given messages. The messages shall be placed in a temporary file and the utility named by the EDITOR variable is
invoked to edit each file in sequence. The default EDITOR is unspecified.
The edit command does not modify the contents of those messages in the mailbox.
Exit
- Synopsis:
-
ex[it]x[it]
Exit from mailx without changing the mailbox. No messages shall be saved in the mbox (see also quit).
Change Folder
- Synopsis:
-
fi[le] [file]fold[er] [file]
Quit (see the quit command) from the current file of messages and read in the file named by the pathname file. If
no argument is given, the name and status of the current mailbox shall be written.
Several unquoted special characters shall be recognized when used as file names, with the following substitutions:
- %
- The system mailbox for the invoking user.
- %user
- The system mailbox for user.
- #
- The previous file.
- &
- The current mbox.
- +file
- The named file in the folder directory. (See the folder variable.)
The default file shall be the current mailbox.
Display List of Folders
- Synopsis:
-
folders
Write the names of the files in the directory set by the folder variable. The command specified by the LISTER
environment variable shall be used (see the ENVIRONMENT VARIABLES section).
Follow Up Specified Messages
- Synopsis:
-
fo[llowup] [message]F[ollowup] [msglist]
In the lowercase form, respond to a message, recording the response in a file whose name is derived from the author of the
message. See also the save and copy commands and outfolder.
In the capitalized form, respond to the first message in the msglist, sending the message to the author of each message
in the msglist. The subject line shall be taken from the first message and the response shall be recorded in a file whose
name is derived from the author of the first message. See also the Save and Copy commands and outfolder.
Both forms shall override the record variable, if set.
Display Header Summary for Specified Messages
- Synopsis:
-
f[rom] [msglist]
Write the header summary for the specified messages.
Display Header Summary
- Synopsis:
-
h[eaders] [message]
Write the page of headers that includes the message specified. If the message argument is not specified, the current
message shall not change. However, if the message argument is specified, the current message shall become the message that
appears at the top of the page of headers that includes the message specified. The screen variable sets the number of
headers per page. See also the z command.
Help
- Synopsis:
-
hel[p]?
Write a summary of commands.
Hold Messages
- Synopsis:
-
ho[ld] [msglist]pre[serve] [msglist]
Mark the messages in msglist to be retained in the mailbox when mailx terminates. This shall override any commands
that might previously have marked the messages to be deleted. During the current invocation of mailx, only the
delete, dp, or dt commands shall remove the preserve marking of a message.
Execute Commands Conditionally
- Synopsis:
-
i[f] s|r
mail-commands
el[se]
mail-commands
en[dif]
Execute commands conditionally, where if s executes the following mail-commands, up to an else or
endif, if the program is in Send Mode, and if r shall cause the mail-commands to be executed only in
Receive Mode.
List Available Commands
- Synopsis:
-
l[ist]
Write a list of all commands available. No explanation shall be given.
Mail a Message
- Synopsis:
-
m[ail] address...
Mail a message to the specified addresses or aliases.
Direct Messages to mbox
- Synopsis:
-
mb[ox] [msglist]
Arrange for the given messages to end up in the mbox save file when mailx terminates normally. See MBOX .
See also the exit and quit commands.
Process Next Specified Message
- Synopsis:
-
n[ext] [message]
If the current message has not been written (for example, by the print command) since mailx started or since any
other message was the current message, behave as if the print command was entered. Otherwise, if there is an undeleted
message after the current message, make it the current message and behave as if the print command was entered. Otherwise, an
informational message to the effect that there are no further messages in the mailbox shall be written, followed by the
mailx prompt.
Pipe Message
- Synopsis:
-
pi[pe] [[msglist] command]| [[msglist] command]
Pipe the messages through the given command by invoking the command interpreter specified by SHELL with two
arguments: -c and command. (See also sh -c.) The application shall
ensure that the command is given as a single argument. Quoting, described previously, can be used to accomplish this. If no
arguments are given, the current message shall be piped through the command specified by the value of the cmd variable. If
the page variable is set, a <form-feed> shall be inserted after each message.
Display Message with Headers
- Synopsis:
-
P[rint] [msglist]T[ype] [msglist]
Write the specified messages, including all header lines, to standard output. Override suppression of lines by the
discard, ignore, and retain commands. If crt is set, the messages longer than the number of lines
specified by the crt variable shall be paged through the command specified by the PAGER environment variable.
Display Message
- Synopsis:
-
p[rint] [msglist]t[ype] [msglist]
Write the specified messages to standard output. If crt is set, the messages longer than the number of lines specified by
the crt variable shall be paged through the command specified by the PAGER environment variable.
Quit
- Synopsis:
-
q[uit]
end-of-file
Terminate mailx, storing messages that were read in mbox (if the current mailbox is the system mailbox and unless
hold is set), deleting messages that have been explicitly saved (unless keepsave is set), discarding messages that
have been deleted, and saving all remaining messages in the mailbox.
Reply to a Message List
- Synopsis:
-
R[eply] [msglist]R[espond] [msglist]
Mail a reply message to the sender of each message in the msglist. The subject line shall be formed by concatenating
Re: <space> (unless it already begins with that string) and the subject from the first message. If record is
set to a filename, the response shall be saved at the end of that file.
See also the flipr variable.
Reply to a Message
- Synopsis:
-
r[eply] [message]r[espond] [message]
Mail a reply message to all recipients included in the header of the message. The subject line shall be formed by concatenating
Re: <space> (unless it already begins with that string) and the subject from the message. If record is set to a
filename, the response shall be saved at the end of that file.
See also the flipr variable.
Retain Header Fields
- Synopsis:
-
ret[ain] [header-field...]
Retain the specified header fields when writing messages. This command shall override all discard and ignore
commands. The comparison of header fields shall be in a case-insensitive manner. If no arguments are specified, write a list of the
currently retained header fields to standard output; the listing need not reflect the same order of header fields that were
entered.
Save Messages
- Synopsis:
-
s[ave] [file]s[ave] [msglist] fileS[ave] [msglist]
Save the specified messages in the file named by the pathname file, or the mbox if the file argument is
omitted. The file shall be created if it does not exist; otherwise, the messages shall be appended to the file. The message shall
be put in the state saved, and shall behave as specified in the description of the saved state when the current
mailbox is exited by the quit or file command.
In the capitalized form, save the specified messages in a file whose name is derived from the author of the first message. The
name of the file shall be taken to be the author's name with all network addressing stripped off. See also the Copy,
followup, and Followup commands and outfolder variable.
Set Variables
- Synopsis:
-
se[t] [name[=[string]] ...] [name=number ...] [noname ...]
Define one or more variables called name. The variable can be given a null, string, or numeric value. Quoting and
backslash escapes can occur anywhere in string, as described previously, as if the string portion of the argument
were the entire argument. The forms name and name= shall be equivalent to name="" for variables that take
string values. The set command without arguments shall write a list of all defined variables and their values. The no
name form shall be equivalent to unset name.
Invoke a Shell
- Synopsis:
-
sh[ell]
Invoke an interactive command interpreter (see also SHELL ).
Display Message Size
- Synopsis:
-
si[ze] [msglist]
Write the size in bytes of each of the specified messages.
Read mailx Commands From a File
- Synopsis:
-
so[urce] file
Read and execute commands from the file named by the pathname file and return to command mode.
Display Beginning of Messages
- Synopsis:
-
to[p] [msglist]
Write the top few lines of each of the specified messages. If the toplines variable is set, it is taken as the number of
lines to write. The default shall be 5.
Touch Messages
- Synopsis:
-
tou[ch] [msglist]
Touch the specified messages. If any message in msglist is not specifically deleted nor saved in a file, it shall be
placed in the mbox upon normal termination. See exit and quit.
Delete Aliases
- Synopsis:
-
una[lias] [alias]...
Delete the specified alias names. If a specified alias does not exist, the results are unspecified.
Undelete Messages
- Synopsis:
-
u[ndelete] [msglist]
Change the state of the specified messages from deleted to read. If autoprint is set, the last message of those restored
shall be written. If msglist is not specified, the message shall be selected as follows:
-
If there are any deleted messages that follow the current message, the first of these shall be chosen.
-
Otherwise, the last deleted message that also precedes the current message shall be chosen.
Unset Variables
- Synopsis:
-
uns[et] name...
Cause the specified variables to be erased.
Edit Message with Full-Screen Editor
- Synopsis:
-
v[isual] [msglist]
Edit the given messages with a screen editor. Each message shall be placed in a temporary file, and the utility named by the
VISUAL variable shall be invoked to edit each file in sequence. The default editor shall be vi.
The visual command does not modify the contents of those messages in the mailbox.
Write Messages to a File
- Synopsis:
-
w[rite] [msglist] file
Write the given messages to the file specified by the pathname file, minus the message header. Otherwise, it shall be
equivalent to the save command.
Scroll Header Display
- Synopsis:
-
z[+|-]
Scroll the header display forward (if '+' is specified or if no option is specified) or backward (if '-' is
specified) one screenful. The number of headers written shall be set by the screen variable.
Invoke Shell Command
- Synopsis:
-
!command
Invoke the command interpreter specified by SHELL with two arguments: -c and command. (See also sh -c.) If the bang variable is set, each unescaped occurrence of '!' in
command shall be replaced with the command executed by the previous ! command or ˜! command escape.
Null Command
- Synopsis:
-
# comment
This null command (comment) shall be ignored by mailx.
Display Current Message Number
- Synopsis:
-
=
Write the current message number.
Command Escapes in mailx
The following commands can be entered only from input mode, by beginning a line with the escape character (by default, tilde (
'˜' )). See the escape variable description for changing this special character. The format for the commands
shall be:
<escape-character><command-char><separator>[<arguments>]
where the <separator> can be zero or more <blank>s.
In the following descriptions, the application shall ensure that the argument command (but not mailx-command) is a
shell command string. Any string acceptable to the command interpreter specified by the SHELL variable when it is invoked as
SHELL -c command_string shall be valid. The command can be presented as multiple arguments (that is, quoting
is not required).
Command escapes that are listed with msglist or mailx-command arguments are invalid in Send Mode and produce
unspecified results.
- ˜! command
- Invoke the command interpreter specified by SHELL with two arguments: -c and command; and then return to
input mode. If the bang variable is set, each unescaped occurrence of '!' in command shall be replaced with
the command executed by the previous ! command or ˜! command escape.
- ˜.
- Simulate end-of-file (terminate message input).
- ˜: mailx-command, ˜_ mailx-command
Perform the command-level request.- ˜?
- Write a summary of command escapes.
- ˜A
- This shall be equivalent to ˜i Sign.
- ˜a
- This shall be equivalent to ˜i sign.
- ˜b name...
- Add the names to the blind carbon copy ( Bcc) list.
- ˜c name...
- Add the names to the carbon copy ( Cc) list.
- ˜d
- Read in the dead-letter file. See DEAD for a description of this file.
- ˜e
- Invoke the editor, as specified by the EDITOR environment variable, on the partial message.
- ˜f [msglist]
- Forward the specified messages. The specified messages shall be inserted into the current message without alteration. This
command escape also shall insert message headers into the message with field selection affected by the discard,
ignore, and retain commands.
- ˜F [msglist]
- This shall be the equivalent of the ˜f command escape, except that all headers shall be included in the message,
regardless of previous discard, ignore, and retain commands.
- ˜h
- If standard input is a terminal, prompt for a Subject line and the To, Cc, and Bcc lists. Other
implementation-defined headers may also be presented for editing. If the field is written with an initial value, it can be edited
as if it had just been typed.
- ˜i string
- Insert the value of the named variable, followed by a <newline>, into the text of the message. If the string is unset or
null, the message shall not be changed.
- ˜m [msglist]
- Insert the specified messages into the message, prefixing non-empty lines with the string in the indentprefix variable.
This command escape also shall insert message headers into the message, with field selection affected by the discard,
ignore, and retain commands.
- ˜M [msglist]
- This shall be the equivalent of the ˜m command escape, except that all headers shall be included in the message,
regardless of previous discard, ignore, and retain commands.
- ˜p
- Write the message being entered. If the message is longer than crt lines (see Internal
Variables in mailx ), the output shall be paginated as described for the PAGER variable.
- ˜q
- Quit (see the quit command) from input mode by simulating an interrupt. If the body of the message is not empty, the
partial message shall be saved in the dead-letter file. See DEAD for a description of this file.
- ˜r file, ˜<
file, ˜r !command, ˜< !command
Read in the file specified by the pathname file. If the argument begins with an exclamation mark ( '!' ), the rest
of the string shall be taken as an arbitrary system command; the command interpreter specified by SHELL shall be invoked
with two arguments: -c and command. The standard output of command shall be inserted into the message.- ˜s string
- Set the subject line to string.
- ˜t name...
- Add the given names to the To list.
- ˜v
- Invoke the full-screen editor, as specified by the VISUAL environment variable, on the partial message.
- ˜w file
- Write the partial message, without the header, onto the file named by the pathname file. The file shall be created or
the message shall be appended to it if the file exists.
- ˜x
- Exit as with ˜q, except the message shall not be saved in the dead-letter file.
- ˜| command
- Pipe the body of the message through the given command by invoking the command interpreter specified by SHELL
with two arguments: -c and command. If the command returns a successful exit status, the standard output of
the command shall replace the message. Otherwise, the message shall remain unchanged. If the command fails, an error message
giving the exit status shall be written.
The standard developers felt strongly that a method for applications to send messages to specific users was necessary. The
obvious example is a batch utility, running non-interactively, that wishes to communicate errors or results to a user. However, the
actual format, delivery mechanism, and method of reading the message are clearly beyond the scope of this volume of
IEEE Std 1003.1-2001.
The intent of this command is to provide a simple, portable interface for sending messages non-interactively. It merely defines
a "front-end" to the historical mail system. It is suggested that implementations explicitly denote the sender and recipient in
the body of the delivered message. Further specification of formats for either the message envelope or the message itself were
deliberately not made, as the industry is in the midst of changing from the current standards to a more internationalized standard
and it is probably incorrect, at this time, to require either one.
Implementations are encouraged to conform to the various delivery mechanisms described in the CCITT X.400 standards or to the
equivalent Internet standards, described in Internet Request for Comment (RFC) documents RFC 819, RFC 822, RFC 920,
RFC 921, and RFC 1123.
Many historical systems modified each body line that started with From by prefixing the 'F' with
'>' . It is unnecessary, but allowed, to do that when the string does not follow a blank line because it cannot be
confused with the next header.
The edit and visual commands merely edit the specified messages in a temporary file. They do not modify the
contents of those messages in the mailbox; such a capability could be added as an extension, such as by using different command
names.
The restriction on a subject line being {LINE_MAX}-10 bytes is based on the historical format that consumes 10 bytes for
Subject: and the trailing <newline>. Many historical mailers that a message may encounter on other systems are
not able to handle lines that long, however.
Like the utilities logger and lp,
mailx admittedly is difficult to test. This was not deemed sufficient justification to exclude this utility from this volume
of IEEE Std 1003.1-2001. It is also arguable that it is, in fact, testable, but that the tests themselves are not
portable.
When mailx is being used by an application that wishes to receive the results as if none of the User Portability
Utilities option features were supported, the DEAD environment variable must be set to /dev/null. Otherwise, it may
be subject to the file creations described in mailx ASYNCHRONOUS EVENTS. Similarly, if the MAILRC environment
variable is not set to /dev/null, historical versions of mailx and Mail read initialization commands from a
file before processing begins. Since the initialization that a user specifies could alter the contents of messages an application
is trying to send, such applications must set MAILRC to /dev/null.
The description of LC_TIME uses "may affect" because many historical implementations do not or cannot manipulate the
date and time strings in the incoming mail headers. Some headers found in incoming mail do not have enough information to determine
the timezone in which the mail originated, and, therefore, mailx cannot convert the date and time strings into the internal
form that then is parsed by routines like strftime() that can take LC_TIME
settings into account. Changing all these times to a user-specified format is allowed, but not required.
The paginator selected when PAGER is null or unset is partially unspecified to allow the System V historical practice of
using pg as the default. Bypassing the pagination function, such as by declaring that cat is the paginator, would not meet with the intended meaning of this description. However, any
"portable user" would have to set PAGER explicitly to get his or her preferred paginator on all systems. The paginator
choice was made partially unspecified, unlike the VISUAL editor choice (mandated to be vi) because most historical pagers follow a common theme of user input, whereas editors differ
dramatically.
Options to specify addresses as cc (carbon copy) or bcc (blind carbon copy) were considered to be format details
and were omitted.
A zero exit status implies that all messages were sent, but it gives no assurances that any of them were actually
delivered. The reliability of the delivery mechanism is unspecified and is an appropriate marketing distinction between
systems.
In order to conform to the Utility Syntax Guidelines, a solution was required to the optional file option-argument to
-f. By making file an operand, the guidelines are satisfied and users remain portable. However, it does force
implementations to support usage such as:
mailx -fin mymail.box
The no name method of unsetting variables is not present in all historical systems, but it is in System V and
provides a logical set of commands corresponding to the format of the display of options from the mailx set command without arguments.
The ask and asksub variables are the names selected by BSD and System V, respectively, for the same feature. They
are synonyms in this volume of IEEE Std 1003.1-2001.
The mailx echo command was not documented in the BSD version and has been
omitted here because it is not obviously useful for interactive users.
The default prompt on the System V mailx is a question mark, on BSD Mail an ampersand. Since this volume of
IEEE Std 1003.1-2001 chose the mailx name, it kept the System V default, assuming that BSD users would not have
difficulty with this minor incompatibility (that they can override).
The meanings of r and R are reversed between System V mailx and SunOS Mail. Once again, since this
volume of IEEE Std 1003.1-2001 chose the mailx name, it kept the System V default, but allows the SunOS user to
achieve the desired results using flipr, an internal variable in System V mailx, although it has not been documented
in the SVID.
The indentprefix variable, the retain and unalias commands, and the ˜F and ˜M
command escapes were adopted from 4.3 BSD Mail.
The version command was not included because no sufficiently general specification of the version information could be
devised that would still be useful to a portable user. This command name should be used by suppliers who wish to provide version
information about the mailx command.
The "implementation-specific (unspecified) system start-up file" historically has been named /etc/mailx.rc, but this
specific name and location are not required.
The intent of the wording for the next command is that if any command has already displayed the current message it should
display a following message, but, otherwise, it should display the current message. Consider the command sequence:
next 3
delete 3
next
where the autoprint option was not set. The normative text specifies that the second next command should display a
message following the third message, because even though the current message has not been displayed since it was set by the
delete command, it has been displayed since the current message was anything other than message number 3. This does not
always match historical practice in some implementations, where the command file address followed by next (or the default
command) would skip the message for which the user had searched.