MAILX(1P) POSIX Programmer's Manual MAILX(1P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
Linux manual page for details of Linux behavior), or the interface may
not be implemented on Linux.
NAME
mailx - process messages
SYNOPSIS
Send Mode
mailx [-s subject] address...
Receive Mode
mailx -e
mailx [-HiNn][-F][-u user]
mailx -f[-HiNn][-F][file]
DESCRIPTION
The mailx utility provides a message sending and receiving facility.
It has two major modes, selected by the options used: Send Mode and
Receive Mode.
On systems that do not support the User Portability Utilities option,
an application using mailx shall have the ability to send messages in
an unspecified manner (Send Mode). Unless the first character of one or
more lines is tilde ( '~' ), all characters in the input message shall
appear in the delivered message, but additional characters may be
inserted in the message before it is retrieved.
On systems supporting the User Portability Utilities option, mail-
receiving capabilities and other interactive features, Receive Mode,
described below, also shall be enabled.
Send Mode
Send Mode can be used by applications or users to send messages from
the text in standard input.
Receive Mode
Receive Mode is more oriented towards interactive users. Mail can be
read and sent in this interactive mode.
When reading mail, mailx provides commands to facilitate saving, delet-
ing, and responding to messages. When sending mail, mailx allows edit-
ing, reviewing, and other modification of the message as it is entered.
Incoming mail shall be stored in one or more unspecified locations for
each user, collectively called the system mailbox for that user. When
mailx is invoked in Receive Mode, the system mailbox shall be the
default place to find new mail. As messages are read, they shall be
marked to be moved to a secondary file for storage, unless specific
action is taken. This secondary file is called the mbox and is normally
located in the directory referred to by the HOME environment variable
(see MBOX in the ENVIRONMENT VARIABLES section for a description of
this file). Messages shall remain in this file until explicitly
removed. When the -f option is used to read mail messages from sec-
ondary files, messages shall be retained in those files unless specifi-
cally removed. All three of these locations-system mailbox, mbox, and
secondary file-are referred to in this section as simply "mailboxes",
unless more specific identification is required.
OPTIONS
The mailx utility shall conform to the Base Definitions volume of
IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported. (Only the -s subject option
shall be required on all systems. The other options are required only
on systems supporting the User Portability Utilities option.)
-e Test for the presence of mail in the system mailbox. The mailx
utility shall write nothing and exit with a successful return
code if there is mail to read.
-f Read messages from the file named by the file operand instead of
the system mailbox. (See also folder.) If no file operand is
specified, read messages from mbox instead of the system mail-
box.
-F Record the message in a file named after the first recipient.
The name is the login-name portion of the address found first on
the To: line in the mail header. Overrides the record variable,
if set (see Internal Variables in mailx .)
-H Write a header summary only.
-i Ignore interrupts. (See also ignore.)
-n Do not initialize from the system default start-up file. See the
EXTENDED DESCRIPTION section.
-N Do not write an initial header summary.
-s subject
Set the Subject header field to subject. All characters in the
subject string shall appear in the delivered message. The
results are unspecified if subject is longer than {LINE_MAX} -
10 bytes or contains a <newline>.
-u user
Read the system mailbox of the login name user. This shall only
be successful if the invoking user has the appropriate privi-
leges to read the system mailbox of that user.
OPERANDS
The following operands shall be supported:
address
Addressee of message. When -n is specified and no user start-up
files are accessed (see the EXTENDED DESCRIPTION section), the
user or application shall ensure this is an address to pass to
the mail delivery system. Any system or user start-up files may
enable aliases (see alias under Commands in mailx ) that may
modify the form of address before it is passed to the mail
delivery system.
file A pathname of a file to be read instead of the system mailbox
when -f is specified. The meaning of the file option-argument
shall be affected by the contents of the folder internal vari-
able; see Internal Variables in mailx .
STDIN
When mailx is invoked in Send Mode (the first synopsis line), standard
input shall be the message to be delivered to the specified addresses.
When in Receive Mode, user commands shall be accepted from stdin. If
the User Portability Utilities option is not supported, standard input
lines beginning with a tilde ( '~' ) character produce unspecified
results.
If the User Portability Utilities option is supported, then in both
Send and Receive Modes, standard input lines beginning with the escape
character (usually tilde ( '~' )) shall affect processing as described
in Command Escapes in mailx .
INPUT FILES
When mailx is used as described by this volume of IEEE Std 1003.1-2001,
the file option-argument (see the -f option) and the mbox shall be text
files containing mail messages, formatted as described in the OUTPUT
FILES section. The nature of the system mailbox is unspecified; it need
not be a file.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of
mailx:
DEAD Determine the pathname of the file in which to save partial mes-
sages in case of interrupts or delivery errors. The default
shall be dead.letter in the directory named by the HOME vari-
able. The behavior of mailx in saving partial messages is
unspecified if the User Portability Utilities option is not sup-
ported and DEAD is not defined with the value /dev/null.
EDITOR Determine the name of a utility to invoke when the edit (see
Commands in mailx ) or ~e (see Command Escapes in mailx ) com-
mand is used. The default editor is unspecified. On XSI-con-
formant systems it is ed. The effects of this variable are
unspecified if the User Portability Utilities option is not sup-
ported.
HOME Determine the pathname of the user's home directory.
LANG Provide a default value for the internationalization variables
that are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari-
ables for the precedence of internationalization variables used
to determine the values of locale categories.)
LC_ALL If set to a non-empty string value, override the values of all
the other internationalization variables.
LC_CTYPE
Determine the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte as
opposed to multi-byte characters in arguments and input files)
and the handling of case-insensitive address and header-field
comparisons.
LC_TIME
Determine the format and contents of the date and time strings
written by mailx.
LC_MESSAGES
Determine the locale that should be used to affect the format
and contents of diagnostic messages written to standard error
and informative messages written to standard output.
LISTER Determine a string representing the command for writing the con-
tents of the folder directory to standard output when the fold-
ers command is given (see folders in Commands in mailx ). Any
string acceptable as a command_string operand to the sh -c com-
mand shall be valid. If this variable is null or not set, the
output command shall be ls. The effects of this variable are
unspecified if the User Portability Utilities option is not sup-
ported.
MAILRC Determine the pathname of the start-up file. The default shall
be .mailrc in the directory referred to by the HOME environment
variable. The behavior of mailx is unspecified if the User
Portability Utilities option is not supported and MAILRC is not
defined with the value /dev/null.
MBOX Determine a pathname of the file to save messages from the sys-
tem mailbox that have been read. The exit command shall override
this function, as shall saving the message explicitly in another
file. The default shall be mbox in the directory named by the
HOME variable. The effects of this variable are unspecified if
the User Portability Utilities option is not supported.
NLSPATH
Determine the location of message catalogs for the processing of
LC_MESSAGES .
PAGER Determine a string representing an output filtering or pagina-
tion command for writing the output to the terminal. Any string
acceptable as a command_string operand to the sh -c command
shall be valid. When standard output is a terminal device, the
message output shall be piped through the command if the mailx
internal variable crt is set to a value less the number of lines
in the message; see Internal Variables in mailx . If the PAGER
variable is null or not set, the paginator shall be either more
or another paginator utility documented in the system documenta-
tion. The effects of this variable are unspecified if the User
Portability Utilities option is not supported.
SHELL Determine the name of a preferred command interpreter. The
default shall be sh. The effects of this variable are unspeci-
fied if the User Portability Utilities option is not supported.
TERM If the internal variable screen is not specified, determine the
name of the terminal type to indicate in an unspecified manner
the number of lines in a screenful of headers. If TERM is not
set or is set to null, an unspecified default terminal type
shall be used and the value of a screenful is unspecified. The
effects of this variable are unspecified if the User Portability
Utilities option is not supported.
TZ This variable may determine the timezone used to calculate date
and time strings written by mailx. If TZ is unset or null, an
unspecified default timezone shall be used.
VISUAL Determine a pathname of a utility to invoke when the visual com-
mand (see Commands in mailx ) or ~v command-escape (see Command
Escapes in mailx ) is used. If this variable is null or not set,
the full-screen editor shall be vi. The effects of this vari-
able are unspecified if the User Portability Utilities option is
not supported.
ASYNCHRONOUS EVENTS
When mailx is in Send Mode and standard input is not a terminal, it
shall take the standard action for all signals.
In Receive Mode, or in Send Mode when standard input is a terminal, if
a SIGINT signal is received:
1. If in command mode, the current command, if there is one, shall be
aborted, and a command-mode prompt shall be written.
2. If in input mode:
a. If ignore is set, mailx shall write "@\n", discard the current
input line, and continue processing, bypassing the message-
abort mechanism described in item 2b.
b. If the interrupt was received while sending mail, either when
in Receive Mode or in Send Mode, a message shall be written,
and another subsequent interrupt, with no other intervening
characters typed, shall be required to abort the mail message.
If in Receive Mode and another interrupt is received, a com-
mand-mode prompt shall be written. If in Send Mode and another
interrupt is received, mailx shall terminate with a non-zero
status.
In both cases listed in item b, if the message is not empty:
i. If save is enabled and the file named by DEAD can be
created, the message shall be written to the file named
by DEAD. If the file exists, the message shall be
written to replace the contents of the file.
ii. If save is not enabled, or the file named by DEAD can-
not be created, the message shall not be saved.
The mailx utility shall take the standard action for all other signals.
STDOUT
In command and input modes, all output, including prompts and messages,
shall be written to standard output.
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
Various mailx commands and command escapes can create or add to files,
including the mbox, the dead-letter file, and secondary mailboxes. When
mailx is used as described in this volume of IEEE Std 1003.1-2001,
these files shall be text files, formatted as follows: line beginning
with From<space>
[one or more header-lines; see Commands in mailx ]
empty line
[zero or more body lines
empty line]
[line beginning with From<space>...]
where each message begins with the From <space> line shown, preceded by
the beginning of the file or an empty line. (The From <space> line is
considered to be part of the message header, but not one of the header-
lines referred to in Commands in mailx ; thus, it shall not be affected
by the discard, ignore, or retain commands.) The formats of the remain-
der of the From <space> line and any additional header lines are
unspecified, except that none shall be empty. The format of a message
body line is also unspecified, except that no line following an empty
line shall start with From <space>; mailx shall modify any such user-
entered message body lines (following an empty line and beginning with
From <space>) by adding one or more characters to precede the 'F' ; it
may add these characters to From <space> lines that are not preceded by
an empty line.
When a message from the system mailbox or entered by the user is not a
text file, it is implementation-defined how such a message is stored in
files written by mailx.
EXTENDED DESCRIPTION
The entire EXTENDED DESCRIPTION section shall apply only to implementa-
tions 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 porta-
ble to non-internationalized systems, and so on. Under these circum-
stances, 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 mes-
sage 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 com-
mands 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 com-
mands 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 envi-
ronmental 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 termina-
tion 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 mes-
sage, 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 (mes-
sage) 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 mes-
sage 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 mail-
box.
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 com-
mand; 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 sum-
mary 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:
1. Establish all variables at their stated default values.
2. Process command line options, overriding corresponding default val-
ues.
3. Import any of the DEAD, EDITOR, MBOX, LISTER , PAGER, SHELL,
or VISUAL variables that are present in the environment, overriding
the corresponding default values.
4. Read mailx commands from an unspecified system start-up file,
unless the -n option is given, to initialize any internal mailx
variables and aliases.
5. 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 con-
tinue 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 spec-
ifications 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 speci-
fied 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 implementa-
tion-defined.
debug Enable verbose diagnostics for debugging. Messages are not
delivered. The default shall be nodebug.
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 addi-
tion 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 process-
ing 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 vari-
able 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 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 enter-
ing 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 head-
ers 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 char-
acter sequences '\t' and '\n' shall be recognized in the vari-
able 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 char-
acter sequences '\t' and '\n' shall be recognized in the vari-
able 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 preced-
ing 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 begin-
ning 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 dis-
carded and the next line shall continue the command.
Filenames, where expected, shall be subjected to the following trans-
formations, 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 speci-
fied 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 AT 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 writ-
ten as described for the print command (see the print command); other-
wise, 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 cur-
rent message shall be written only if it was set to a message after the
last message deleted by the command. Otherwise, an informational mes-
sage 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 vari-
able.)
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 vari-
able. 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 mes-
sage 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 com-
mands.
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. Other-
wise, 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 accom-
plish 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 cur-
rent mailbox is the system mailbox and unless hold is set), deleting
messages that have been explicitly saved (unless keepsave is set), dis-
carding messages that have been deleted, and saving all remaining mes-
sages 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 mes-
sage. 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 mail-
box 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 specifi-
cally 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 vari-
able shall be invoked to edit each file in sequence. The default edi-
tor 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 num-
ber 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 com-
mand 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 begin-
ning 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 argu-
ments: -c and command; and then return to input mode. If the
bang variable is set, each unescaped occurrence of '!' in com-
mand 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 vari-
able, on the partial message.
~f [msglist]
Forward the specified messages. The specified messages shall be
inserted into the current message without alteration. This com-
mand 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 mes-
sage, 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 argu-
ments: -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 envi-
ronment 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 invok-
ing the command interpreter specified by SHELL with two argu-
ments: -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.
EXIT STATUS
When the -e option is specified, the following exit values are
returned:
0 Mail was found.
>0 Mail was not found or an error occurred.
Otherwise, the following exit values are returned:
0 Successful completion; note that this status implies that all
messages were sent, but it gives no assurances that any of them
were actually delivered.
>0 An error occurred.
CONSEQUENCES OF ERRORS
When in input mode (Receive Mode) or Send Mode:
* If an error is encountered processing a command escape (see Command
Escapes in mailx ), a diagnostic message shall be written to stan-
dard error, and the message being composed may be modified, but this
condition shall not prevent the message from being sent.
* Other errors shall prevent the sending of the message.
When in command mode:
* Default.
The following sections are informative.
APPLICATION USAGE
Delivery of messages to remote systems requires the existence of commu-
nication paths to such systems. These need not exist.
Input lines are limited to {LINE_MAX} bytes, but mailers between sys-
tems may impose more severe line-length restrictions. This volume of
IEEE Std 1003.1-2001 does not place any restrictions on the length of
messages handled by mailx, and for delivery of local messages the only
limitations should be the normal problems of available disk space for
the target mail file. When sending messages to external machines,
applications are advised to limit messages to less than 100000 bytes
because some mail gateways impose message-length restrictions.
The format of the system mailbox is intentionally unspecified. Not all
systems implement system mailboxes as flat files, particularly with the
advent of multimedia mail messages. Some system mailboxes may be multi-
ple files, others records in a database. The internal format of the
messages themselves is specified with the historical format from Ver-
sion 7, but only after the messages have been saved in some file other
than the system mailbox. This was done so that many historical applica-
tions expecting text-file mailboxes are not broken.
Some new formats for messages can be expected in the future, probably
including binary data, bit maps, and various multimedia objects. As
described here, mailx is not prohibited from handling such messages,
but it must store them as text files in secondary mailboxes (unless
some extension, such as a variable or command line option, is used to
change the stored format). Its method of doing so is implementation-
defined and might include translating the data into text file-compati-
ble or readable form or omitting certain portions of the message from
the stored output.
The discard and ignore commands are not inverses of the retain command.
The retain command discards all header-fields except those explicitly
retained. The discard command keeps all header-fields except those
explicitly discarded. If headers exist on the retained header list,
discard and ignore commands are ignored.
EXAMPLES
None.
RATIONALE
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 mech-
anism, 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 enve-
lope or the message itself were deliberately not made, as the industry
is in the midst of changing from the current standards to a more inter-
nationalized standard and it is probably incorrect, at this time, to
require either one.
Implementations are encouraged to conform to the various delivery mech-
anisms 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, how-
ever.
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 ini-
tialization commands from a file before processing begins. Since the
initialization that a user specifies could alter the contents of mes-
sages 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 unspec-
ified 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 edi-
tor 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. How-
ever, 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 histor-
ical systems, but it is in System V and provides a logical set of com-
mands 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 com-
mand.
The "implementation-specific (unspecified) system start-up file" his-
torically 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. Con-
sider 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 com-
mand) would skip the message for which the user had searched.
FUTURE DIRECTIONS
None.
SEE ALSO
Shell Command Language, ed, ls, more, vi
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 MAILX(1P)
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