Linux and Unix mailx command

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About mailx
Syntax
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About mailx

Send and receive mail.

Syntax

mailx [-BDdEFintv~] [-s subject] [-a attachment ] [-c cc-addr] 
      [-b bcc-addr] [-r from-addr] [-h hops] [-A account] 
      [-S variable[=value]] to-addr . . .
mailx [-BDdeEHiInNRv~] [-T name] [-A account] 
      [-S variable[=value]] -f [name]
mailx [-BDdeEinNRv~] [-A account] [-S variable[=value]] [-u user] 

Description

mailx is an intelligent mail processing system, which has a command syntax reminiscent of ed with lines replaced by messages. It is based on Berkeley Mail 8.1, is intended to provide the functionality of the mail command, and offers extensions for MIME, IMAP, POP3, SMTP, and S/MIME. mailx provides enhanced features for interactive use, such as caching and disconnected operation for IMAP, message threading, scoring, and filtering. It is also usable as a mail batch language, both for sending and receiving mail.

Options

-A name Executes an account command (see below) for name after the startup files have been read.
-a file Attach the given file to the message.
-B Make standard input and standard output line-buffered.
-b list Send blind carbon copies to list. list should be a comma-separated list of names.
-c list Send carbon copies to list of addresses.
-D Start in disconnected mode; see the description of the disconnected variable option.
-d Enables debugging messages and disables the actual delivery of messages. Unlike -v, this option is intended for development purposes only.
-e Just check if mail is present in the system mailbox. If yes, return an exit status of zero, else, a non-zero value.
-E If an outgoing message does not contain any text in its first or only message part, do not send it but discard it silently, effectively setting the skipemptybody variable at program startup. This is useful for sending messages from scripts started by cron.
-f [file] Read in the contents of the user's mailbox (or file, if specified) for processing; when mailx is quit, it writes undeleted messages back to this file. The string file is handled as described for the folder command below.
-F Save the message to send in a file named after the local part of the first recipient's address.
-H Print header summaries for all messages and exit.
-h hops Invoke sendmail with the specified hop count. This option has no effect when SMTP is used for sending mail.
-i Ignore tty interrupt signals. This is particularly useful when using mailx on noisy phone lines.
-I Shows the 'Newsgroup:' or 'Article-Id:' fields in the header summary. Only applies when used in combination with -f.
-n Inhibits reading /etc/mail.rc upon startup. This option should be activated for mailx scripts that are invoked on more than one machine, because the contents of that file may differ between them.
-N Inhibits the initial display of message headers when reading mail or editing a mail folder.
-q file Start the message with the contents of the specified file. May be given in send mode only.
-r address Sets the From address. Overrides any from variable specified in environment variables or startup files. Tilde escapes are disabled. The -r address options are passed to the mail transfer agent unless SMTP is used. This option exists for compatibility only; it is recommended to set the from variable directly instead.
-R If opening folders, opens them read-only.
-s subject Specify subject on command line (only the first argument after the -s flag is used as a subject; be careful to quote subjects containing spaces).
-S variable[=value] Sets the internal option variable variable to the optional value value.
-T name Writes the 'Message-Id:' and 'Article-Id:' header fields of each message read in the file name. Implies -I. Compressed files are handled as described for the folder command below.
-t The message to be sent is expected to contain a message header with 'To:', 'Cc:', or 'Bcc:' fields giving its recipients. Recipients specified on the command line are ignored.
-u user Reads the mailbox of user user.
-v Verbose mode. The details of delivery are displayed on the user's terminal.
-V Display version information and exit.
-~ Enable tilde escapes even if not in interactive mode.

Sending Mail

To send a message to one or more people, mailx can be invoked with arguments which are the names of people to whom the mail will be sent. The user is then expected to type in his message, followed by an 'control-D' at the beginning of a line, which signals the end of the message, and implicit approval to send it.

Reading Mail

In normal usage mailx is given no arguments and checks the user's mail out of the mail server, then prints out a one line header of each message found. The current message is initially the first message (numbered 1) and can be printed using the print command which can be abbreviated 'p'). The user can move among the messages much as he moves between lines in ed, with the commands '+' and '-' moving backwards and forwards, and simple numbers.

Disposing of Mail

After examining a message the user can delete ('d') the message, or reply 'r') to it. Deletion causes the mailx program to forget about the message. This is not irreversible; the message can be undeleted ('u') by giving its number, or the mailx session can be aborted by giving the exit ('x') command. Deleted messages will, however, usually disappear never to be seen again.

Specifying Messages

Commands such as print and delete can be given a list of message numbers as arguments to apply to a number of messages at once. Thus 'delete 1 2' deletes messages 1 and 2, while 'delete 1-5' deletes messages 1 through 5. In sorted or threaded mode (see the sort and thread commands), 'delete 1-5' deletes the messages that are located between (and including) messages 1 through 5 in the sorted/threaded order, as shown in the header summary. The following special message names exist:

:n All new messages.
:o All old messages (any not in state read or new).
:u All unread messages.
:d All deleted messages (for the undelete command).
:r All read messages.
:f All 'flagged' messages.
:a All answered messages (see the markanswered variable).
:t All messages marked as draft.
:k All 'killed' messages.
:j All messages that have been classified as junk.
. The current message.
; The message that was previously the current message.
, The parent message of the current message, that is the message with the Message-ID given in the 'In-Reply-To:' field or the last entry of the 'References:' field of the current message.
- The next previous undeleted message, or the next previous deleted message for the undelete command. In sorted/threaded mode, the next previous such message in the sorted/threaded order.
+ The next undeleted message, or the next deleted message for the undelete command. In sorted/threaded mode, the next such message in the sorted/threaded order.
^ The first undeleted message, or the first deleted message for the undelete command. In sorted/threaded mode, the first such message in the sorted/threaded order.
$ The last message. In sorted/threaded mode, the last message in the sorted/threaded order.
&x In threaded mode, selects the message addressed with x, where x is any other message specification, and all messages from the thread that begins at it. Otherwise, it is identical to x. If x is omitted, the thread beginning with the current message is selected.
* All messages.
' All messages that were included in the message list for the previous command.
/string All messages that contain string in the subject field (case ignored). See also the searchheaders variable. If string is empty, the string from the previous specification of that type is used again.
address All messages from address address.
(criterion) All messages that satisfy the given IMAP-style SEARCH criterion. This addressing mode is available with all types of folders; for folders not located on IMAP servers, or for servers unable to execute the SEARCH command, mailx will perform the search locally. Strings must be enclosed by double quotes '"' in their entirety if they contain white space or parentheses; within the quotes, only backslash '\' is recognized as an escape character. All string searches are case-insensitive. When the description indicates that the 'envelope' representation of an address field is used, this means that the search string is checked against both a list constructed as

("real name" "source-route" "local-part" "domain-part")
for each address, and the addresses without real names from the respective header field. Criteria can be nested using parentheses.
(criterion1 criterion2 ... criterionN) All messages that satisfy all of the given criteria.
(or criterion1 criterion2) All messages that satisfy either criterion1 or criterion2, or both. To connect more than two criteria using 'or', (or) specifications have to be nested using additional parentheses, as with '(or a (or b c))'; '(or a b c)' means ((a or b) and c). For a simple 'or' operation of independent criteria on the lowest nesting level, it is possible to achieve similar effects by using three separate criteria, as with '(a) (b) (c)'.
(not criterion) All messages that do not satisfy criterion.
(bcc string) All messages that contain string in the 'envelope' representation of the Bcc: field.
(cc string) All messages that contain string in the 'envelope' representation of the Cc: field.
(from string) All messages that contain string in the 'envelope' representation of the From: field.
(subject string) All messages that contain string in the Subject: field.
(to string) All messages that contain string in the 'envelope' representation of the To: field.
(header name string) All messages that contain string in the specified Name: field.
(body string) All messages that contain string in their body.
(text string) All messages that contain string in their header or body.
(larger size) All messages that are larger than size (in bytes).
(smaller size) All messages that are smaller than size (in bytes).
(before date) All messages that were received before date; date must be in the form d[d]-mon-yyyy, where d[d] is the day of the month as one or two digits, mon is the name of the month (one of 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', or 'Dec'), and yyyy is the year as four digits; e.g. "30-Aug-2004".
(on date) All messages that were received on the specified date.
(since date) All messages that were received since the specified date.
(sentbefore date) All messages that were sent on the specified date.
(senton date) All messages that were sent on the specified date.
(sentsince date) All messages that were sent since the specified date.
() The same criterion as for the previous search. This specification cannot be used as part of another criterion. If the previous command line contained more than one independent criterion, the last of those criteria is used.

A practical method to read a set of messages is to issue a from command with the search criteria first to check for appropriate messages, and then to read each single message by typing ''' (single quote) repeatedly.

Replying To or Originating Mail

The reply command can be used to set up a response to a message, sending it back to the person who it was from. Text the user types in then, up to an end-of-file, defines the contents of the message. While the user is composing a message, mailx treats lines beginning with the character '~' specially. For instance, typing '~m' (alone on a line) will place a copy of the current message into the response right shifting it by a tabstop (see indentprefix variable, below). Other escapes will set up subject fields, add and delete recipients to the message, attach files to it and allow the user to escape to an editor to revise the message or to a shell to run some commands.

Ending A Mail Processing Session

The user can end a mailx session with the quit ('q') command. Messages which have been examined go to the user's mailbox file, unless they have been deleted, in which case they are discarded. Unexamined messages go back to the post office (see the -f option above).

Personal And Systemwide Distribution Lists

It is also possible to create a personal distribution lists so that, for instance, the user can send mail to the word 'cohorts' and have it go to a group of people. Such lists can be defined by placing a line like

alias cohorts bill ozalp jkf mark kridle@ucbcory 

in the file .mailrc in the user's home directory. The current list of such aliases can be displayed with the alias command in mailx. System wide distribution lists can be created by editing /etc/aliases (see sendmail); these are kept in a different syntax. In mail the user sends, personal aliases will be expanded in mail sent to others so that they will be able to reply to the recipients. System wide aliases are not expanded when the mail is sent, but any reply returned to the machine will have the system wide alias expanded as all mail goes through sendmail.

Recipient Address Specifications

When an address is used to name a recipient (in any of To, Cc, or Bcc), names of local mail folders and pipes to external commands can also be specified; the message text is then written to them. The rules are: Any name which starts with a '|' character specifies a pipe, the command string following the '|' is executed and the message is sent to its standard input; any other name which contains a '@' character is treated as a mail address; any other name which starts with a '+' character specifies a folder name; any other name which contains a '/' character but no '!' or '%' character before also specifies a folder name; what remains is treated as a mail address. Compressed folders are handled as described for the folder command below.

MIME Types

For any outgoing attachment, mailx tries to determine the content type. It does this by reading MIME type files whose lines have the following syntax:

type/subtype extension [extension . . .] 

where type/subtype are strings describing the file contents, and extension is the part of a filename starting after the last dot. Any line not immediately beginning with an ASCII alphabetical character is ignored by mailx. If there is a match with the extension of the file to attach, the given type/subtype pair is used. Otherwise, or if the filename has no extension, the content types text/plain or application/octet-stream are used, the first for text or international text files, the second for any file that contains formatting characters other than newlines and horizontal tabs.

Character Sets

mailx normally detects the character set of the terminal using the LC_CTYPE locale setting. If the locale cannot be used appropriately, the ttycharset variable should be set to provide an explicit value. When reading messages, their text is converted to the terminal character set if possible. Unprintable characters and illegal byte sequences are detected and replaced by Unicode substitute characters or question marks ("?") unless the print-all-chars option is set at initialization time.

The character set for outgoing messages is not necessarily the same as the one used on the terminal. If an outgoing text message contains characters not representable in US-ASCII, the character set being used must be declared within its header. Permissible values can be declared using the sendcharsets variable, separated by commas; mailx tries each of the values in order and uses the first appropriate one. If the message contains characters that cannot be represented in any of the given character sets, the message will not be sent, and its text will be saved to the 'dead.letter' file. Messages that contain NUL bytes are not converted.

Outgoing attachments are converted if they are plain text. If the sendcharsets variable contains more than one character set name, the ~@ tilde escape will ask for the character sets for individual attachments if it is invoked without arguments.

Best results are usually achieved when mailx is run in a UTF-8 locale on a UTF-8 capable terminal. In this setup, characters from various countries can be displayed, while it is still possible to use more simple character sets for sending to retain maximum compatibility with older mail clients.

Commands

Each command is typed on a line by itself, and may take arguments following the command word. The command need not be typed in its entirety - the first command which matches the typed prefix is used. For commands which take message lists as arguments, if no message list is given, then the next message forward which satisfies the command's requirements is used. If there are no messages forward of the current message, the search proceeds backwards, and if there are no good messages at all, mailx types 'applicable messages' and aborts the command. If the command begins with a # sign, the line is ignored.

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 are treated literally as part of the argument. A double-quote will be treated literally within single-quotes and vice versa. These special properties of the quote marks occur only when they are paired at the beginning and end of the argument.
  • A backslash outside of the enclosing quotes is discarded and the following character is treated literally as part of the argument.
  • An unquoted backslash at the end of a command line is discarded and the next line continues the command.

Filenames, where expected, are subjected to the following transformations, in sequence:

  • If the filename begins with an unquoted plus sign, and the folder variable is defined, the plus sign will 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 will be unchanged.
  • Shell word expansions are applied to the filename. If more than a single pathname results from this expansion and the command is expecting one file, an error results.

The following commands are provided:

command abbreviation description
-   Print out the preceding message. If given a numeric argument n, goes to the n'th previous message and prints it.
?   Prints a brief summary of commands.
!   Executes the shell (see sh and csh) command which follows.
|   A synonym for the pipe command.
account ac Creates, selects or lists an email account. An account is formed by a group of commands, primarily of those to set variables. With two arguments, of which the second is a '{', the first argument gives an account name, and the following lines create a group of commands for that account until a line containing a single '}' appears. With one argument, the previously created group of commands for the account name is executed, and a folder command is executed for the system mailbox or inbox of that account. Without arguments, the list of accounts and their contents are printed. As an example,

account myisp {
    set folder=imaps://mylogin@imap.myisp.example
    set record=+Sent
    set from="myname@myisp.example (My Name)"
    set smtp=smtp.myisp.example
}
creates an account named 'myisp' which can later be selected by specifying 'account myisp'.
alias a With no arguments, prints out all currently-defined aliases. With one argument, prints out that alias. With more than one argument, creates a new alias or changes an old one.
alternates alt The alternates command is useful if the user has accounts on several machines. It can be used to inform mailx that the listed addresses all belong to the invoking user. When he or she replies to messages, mailx will not send a copy of the message to any of the addresses listed on the alternates list. If the alternates command is given with no argument, the current set of alternate names is displayed.
answered ans Takes a message list and marks each message as a having been answered. This mark has no technical meaning in the mail system; it just causes messages to be marked in the header summary, and makes them specially addressable.
cache   Only applicable to cached IMAP mailboxes; takes a message list and reads the specified messages into the IMAP cache.
call   Calls a macro (see the define command for more information).
cd   Same as chdir.
certsave   Only applicable to S/MIME signed messages. Takes a message list and a file name and saves the certificates contained within the message signatures to the named file in both human-readable and PEM format. The certificates can later be used to send encrypted messages to the messages' originators by setting the smime-encrypt-user@host variable.
chdir   (ch) Changes the user's working directory to that specified, if given. If no directory is given, then changes to the user's login directory.
classify cl Takes a list of messages and examines their contents for characteristics of junk mail using Bayesian filtering. Messages considered to be junk are then marked as such. The junk mail database is not changed.
collapse coll Only applicable to threaded mode. Takes a message list and makes all replies to these messages invisible in header summaries, unless they are in state 'new'.
connect conn If operating in disconnected mode on an IMAP mailbox, switch to online mode and connect to the mail server while retaining the mailbox status. See the description of the disconnected variable for more information.
copy c The copy command does the same thing that save does, except that it does not mark the messages it is used on for deletion when the user quits. Compressed files and IMAP mailboxes are handled as described for the folder command.
Copy C Similar to copy, but saves the messages in a file named after the local part of the sender address of the first message.
decrypt dec For unencrypted messages, this command is identical to copy. Encrypted messages are first decrypted, if possible, and then copied.
Decrypt Dec Similar to decrypt, but saves the messages in a file named after the local part of the sender address of the first message.
define def Defines a macro. A macro definition is a sequence of commands in the following form:

define name { command1 command2 ... commandN } 
Once defined, a macro can be explicitly invoked using the call command, or can be implicitly invoked by setting the folder-hook or folder-hook-fullname variables.
defines   Prints the currently defined macros including their contents.
delete d Takes a list of messages as argument and marks them all as deleted. Deleted messages will not be saved in mbox, nor will they be available for most other commands.
discard   Same as ignore.
disconnect disco If operating in online mode on an IMAP mailbox, switch to disconnected mode while retaining the mailbox status. See the description of the disconnected variable for more information. A list of messages may optionally be given as argument; the respective messages are then read into the cache before the connection is closed. Thus 'disco *' makes the entire current mailbox available for disconnected use.
dp, dt   Deletes the current message and prints the next message. If there is no next message, mailx says 'at EOF'.
draft   Takes a message list and marks each message as a draft. This mark has no technical meaning in the mail system; it just causes messages to be marked in the header summary, and makes them specially addressable.
echo   Echoes its arguments, resolving special names as documented for the folder command. The escape sequences '\a', '\b', '\c', '\f', '\n', '\r', '\t', '\v', '\\', and '\0num' are interpreted as with the echo command.
edit e Takes a list of messages and points the text editor at each one in turn. Modified contents are discarded unless the writebackedited variable is set.
else   Marks the end of the then-part of an if statement and the beginning of the part to take effect if the condition of the if statement is false.
endif   Marks the end of an if statement.
exit ex, x Effects an immediate return to the Shell without modifying the user's system mailbox, his mbox file, or his edit file in -f.
file fi The same as folder.
flag fl Takes a message list and marks the messages as 'flagged' for urgent/special attention. This mark has no technical meaning in the mail system; it merely causes messages to be highlighted in the header summary, and makes them specially addressable.
folders   With no arguments, list the names of the folders in the folder directory. With an existing folder as an argument, lists then names of folders below the named folder; e.g. the command 'folders @' lists the folders on the base level of the current IMAP server. See also the imap-list-depth variable.
folder fold The folder command switches to a new mail file or folder. With no arguments, it tells the user which file he is currently reading. If an argument is given, it will write out changes (such as deletions) the user has made in the current file and read in the new file. Some special conventions are recognized for the name. # means the previous file, % means the invoking user's system mailbox, %user means user's system mailbox, & means the invoking user's mbox file, and +file means a file in the folder directory. %:filespec expands to the same value as filespec, but the file is handled as a system mailbox, e.g. by the mbox and save commands. If the name matches one of the strings defined with the shortcut command, it is replaced by its long form and expanded. If the name ends with .gz or .bz2, it is treated as compressed with gzip or bzip2, respectively. Likewise, if name does not exist, but either name.gz or name.bz2 exists, the compressed file is used. If name refers to a directory with the subdirectories 'tmp', 'new', and 'cur', it is treated as a folder in maildir format. A name of the form

protocol://[user@]host[:port][/file] 
is taken as an Internet mailbox specification. The supported protocols are currently imap (IMAP v4r1), imaps (IMAP with SSL/TLS encryption), pop3 (POP3), and pop3s (POP3 with SSL/TLS encryption). If user contains special characters, in particular '/' or '%', they must be escaped in URL notation, as '%2F' or '%25'. The optional file part applies to IMAP only; if it is omitted, the default 'INBOX' is used. If mailx is connected to an IMAP server, a name of the form @mailbox refers to the mailbox on that server. If the 'folder' variable refers to an IMAP account, the special name '%' selects the 'INBOX' on that account.
Followup F Similar to Respond, but saves the message in a file named after the local part of the first recipient's address.
followup fo Similar to respond, but saves the message in a file named after the local part of the first recipient's address.
followupall   Similar to followup, but responds to all recipients regardless of the flipr and Replyall variables.
followupsender   Similar to Followup, but responds to the sender only regardless of the flipr and Replyall variables.
forward fwd Takes a message and the address of a recipient and forwards the message to him. The text of the original message is included in the new one, with the value of the fwdheading variable printed before. The fwdignore and fwdretain commands specify which header fields are included in the new message. Only the first part of a multipart message is included unless the forward-as-attachment option is set.
Forward Fwd Similar to forward, but saves the message in a file named after the local part of the recipient's address.
from f Takes a list of messages and prints their message headers, piped through the pager if the output does not fit on the screen.
fwdignore   Specifies which header fields are to be ignored with the forward command. This command has no effect when the forward-as-attachment option is set.
fwdretain   Specifies which header fields are to be retained with the forward command. fwdretain overrides fwdignore. This command has no effect when the forward-as-attachment option is set.
good go Takes a list of messages and marks all of them as not being junk mail. Data from these messages is then inserted into the junk mail database for future classification.
headers h Lists the current range of headers, which is an 18-message group. If a '+' argument is given, then the next 18-message group is printed, and if a '-' argument is given, the previous 18-message group is printed.
help   A synonym for ?.
hold ho, or preserve Takes a message list and marks each message therein to be saved in the user's system mailbox instead of in mbox. Does not override the delete command. mailx deviates from the POSIX standard with this command, as a 'next' command issued after 'hold' will display the following message, not the current one.
if   Commands in mailx's startup files can be executed conditionally depending on whether the user is sending or receiving mail with the if command. For example:

if receive 
    commands . . . 
endif 
An else form is also available:

if receive 
    commands . . . 
else 
    commands . . . 
endif 
Note that the only allowed conditions are receive, send, and term (execute command if standard input is a tty).
ignore   Add the list of header fields named to the ignored list. Header fields in the ignore list are not printed on the terminal when a message is printed. This command is very handy for suppression of certain machine-generated header fields. The Type and Print commands can be used to print a message in its entirety, including ignored fields. If ignore is executed with no arguments, it lists the current set of ignored fields.
imap   Sends command strings directly to the current IMAP server. Mailx operates always in IMAP selected state on the current mailbox; commands that change this will produce undesirable results and should be avoided. Useful IMAP commands are:
create Takes the name of an IMAP mailbox as an argument and creates it.
getquotaroot Takes the name of an IMAP mailbox as an argument and prints the quotas that apply to the mailbox. Not all IMAP servers support this command.
namespace Takes no arguments and prints the Personal Namespaces, the Other User's Namespaces, and the Shared Namespaces. Each namespace type is printed in parentheses; if there are multiple namespaces of the same type, inner parentheses separate them. For each namespace, a namespace prefix and a hierarchy separator is listed. Not all IMAP servers support this command.
inc   Same as newmail.
junk j Takes a list of messages and marks all of them as junk mail. Data from these messages is then inserted into the junk mail database for future classification.
kill k Takes a list of messages and 'kills' them. Killed messages are not printed in header summaries, and are ignored by the next command. The kill command also sets the score of the messages to negative infinity, so that subsequent score commands will not unkill them again. Killing is only effective for the current session on a folder; when it is quit, all messages are automatically unkilled.
list   Prints the names of all available commands.
Mail M Similar to mail, but saves the message in a file named after the local part of the first recipient's address.
mail m Takes as argument login names and distribution group names and sends mail to those people.
mbox   Indicate that a list of messages be sent to mbox in the user's home directory when mailx is quit. This is the default action for messages if unless the hold option is set. mailx deviates from the POSIX standard with this command, as a 'next' command issued after 'mbox' will display the following message, not the current one.
move mv Acts like copy, but marks the messages for deletion if they were transferred successfully.
Move Mv Similar to move, but moves the messages to a file named after the local part of the sender address of the first message.
newmail   Checks for new mail in the current folder without committing any changes before. If new mail is present, a message is printed. If the header variable is set, the headers of each new message are also printed.
next n Like +, or CR: goes to the next message in sequence and types it. With an argument list, types the next matching message.
New   Same as unread.
new   Same as unread.
online   Same as connect.
noop   If the current folder is located on an IMAP or POP3 server, a NOOP (No Operation) command is sent. This is a common way to send a "keepalive" request, which keeps a connection from terminating due to inactivity.

Otherwise, no operation is performed.
Pipe Pi Like pipe but also pipes ignored header fields and all parts of MIME multipart/alternative messages.
pipe pi Takes a message list and a shell command and pipes the messages through the command. Without an argument, the current message is piped through the command given by the cmd variable. If the page variable is set, every message is followed by a formfeed character.
preserve pre A synonym for hold.
Print P Like print but also prints out ignored header fields and all parts of MIME multipart/alternative messages. See also print, ignore, and retain.
print p Takes a message list and types out each message on the user's terminal. If the message is a MIME multipart message, all parts with a content type of 'text' or 'message' are shown; the others are hidden except for their headers. Messages are decrypted and converted to the terminal character set if necessary.
probability prob For each word given as argument, the contents of its junk mail database entry are printed.
quit q Terminates the session, saving all undeleted, unsaved messages in the user's mbox file in his or her login directory, preserving all messages marked with hold or preserve or never referenced in his system mailbox, and removing all other messages from his system mailbox. If new mail has arrived during the session, the message 'You have new mail' is given. If given while editing a mailbox file with the -f flag, then the edit file is rewritten. A return to the Shell is effected, unless the rewrite of edit file fails, in which case the user can escape with the exit command.
redirect red Same as resend.
Redirect Red Same as Resend.
remove rem Removes the named folders. The user is asked for confirmation in interactive mode.
rename ren Takes the name of an existing folder and the name for the new folder and renames the first to the second one. Both folders must be of the same type and must be located on the current server for IMAP.
Reply R Reply to originator. Does not reply to other recipients of the original message.
reply r Takes a message list and sends mail to the sender and all recipients of the specified message. The default message must not be deleted.
replyall   Similar to reply, but responds to all recipients regardless of the flipr and Replyall variables.
replysender   Similar to Reply, but responds to the sender only regardless of the flipr and Replyall variables.
Resend   Like resend, but does not add any header lines. This is not a way to hide the sender's identity, but useful for sending a message again to the same recipients.
resend   Takes a list of messages and a user name and sends each message to the named user. 'Resent-From:' and related header fields are prepended to the new copy of the message.
Respond   Same as Reply.
respond   Same as reply.
respondall   Same as replyall.
respondsender   Same as replysender.
retain   Add the list of header fields named to the retained list. Only the header fields in the retain list are shown on the terminal when a message is printed. All other header fields are suppressed. The Type and Print commands can be used to print a message in its entirety. If retain is executed with no arguments, it lists the current set of retained fields.
Save S Similar to save, but saves the messages in a file named after the local part of the sender of the first message instead of taking a filename argument.
save s Takes a message list and a filename and appends each message in turn to the end of the file. If no filename is given, the mbox file is used. The filename in quotes, followed by the line count and character count is echoed on the user's terminal. If editing a system mailbox, the messages are marked for deletion. Compressed files and IMAP mailboxes are handled as described for the -f command line option above.
savediscard   Same as saveignore.
saveignore   Saveignore is to save what ignore is to print and type. Header fields thus marked are filtered out when saving a message by save or when automatically saving to mbox. This command should only be applied to header fields that do not contain information needed to decode the message, as MIME content fields do. If saving messages on an IMAP account, ignoring fields makes it impossible to copy the data directly on the server, thus operation usually becomes much slower.
saveretain   Saveretain is to save what retain is to print and type. Header fields thus marked are the only ones saved with a message when saving by save or when automatically saving to mbox. Saveretain overrides saveignore. The use of this command is strongly discouraged since it may strip header fields that are needed to decode the message correctly.
score sc Takes a message list and a floating point number and adds the number to the score of each given message. All messages start at score 0 when a folder is opened. When the score of a message becomes negative, it is 'killed' with the effects described for the kill command; otherwise if it was negative before and becomes positive, it is 'unkilled'. Scores only refer to the currently opened instance of a folder.
set se With no arguments, prints all variable values, piped through the pager if the output does not fit on the screen. Otherwise, sets option. Arguments are of the form option=value (no space before or after =) or option. Quotation marks may be placed around any part of the assignment statement to quote blanks or tabs, i.e. 'set indentprefix="->"'. If an argument begins with no, as in 'set nosave', the effect is the same as invoking the unset command with the remaining part of the variable ('unset save').
seen   Takes a message list and marks all messages as having been read.
shell sh Invokes an interactive version of the shell.
shortcut   Defines a shortcut name and its string for expansion, as described for the folder command. With no arguments, a list of defined shortcuts is printed.
show Sh Like print, but performs neither MIME decoding nor decryption so that the raw message text is shown.
size   Takes a message list and prints out the size in characters of each message.
sort   Create a sorted representation of the current folder, and change the next command and the addressing modes such that they refer to messages in the sorted order. Message numbers are the same as in regular mode. If the header variable is set, a header summary in the new order is also printed. Possible sorting criteria are:
date Sort the messages by their 'Date:' field, that is by the time they were sent.
from Sort messages by the value of their 'From:' field, that is by the address of the sender. If the showname variable is set, the sender's real name (if any) is used.
size Sort the messages by their size.
score Sort the messages by their score.
status Sort the messages by their message status (new, read, old, etc.).
subject Sort the messages by their subject.
thread Create a threaded order, as with the thread command.
to Sort messages by the value of their 'To:' field, that is by the address of the recipient. If the showname variable is set, the recipient's real name (if any) is used.
source   The source command reads commands from a file.
thread th Create a threaded representation of the current folder, i.e. indent messages that are replies to other messages in the header display, and change the next command and the addressing modes such that they refer to messages in the threaded order. Message numbers are the same as in unthreaded mode. If the header variable is set, a header summary in threaded order is also printed.
top   Takes a message list and prints the top few lines of each. The number of lines printed is controlled by the variable toplines and defaults to five.
touch   Takes a message list and marks the messages for saving in the mbox file. mailx deviates from the POSIX standard with this command, as a 'next' command issued after 'mbox' will display the following message, not the current one.
Type T Identical to the Print command.
type t A synonym for print.
unalias   Takes a list of names defined by alias commands and discards the remembered groups of users. The group names no longer have any significance.
unanswered   Takes a message list and marks each message as not having been answered.
uncollapse unc Only applicable to threaded mode. Takes a message list and makes the message and all replies to it visible in header summaries again. When a message becomes the current message, it is automatically made visible. Also when a message with collapsed replies is printed, all of these are automatically uncollapsed.
undef   Undefines each of the named macros. It is not an error to use a name that does not belong to one of the currently defined macros.
undelete u Takes a message list and marks each message as not being deleted.
undraft   Takes a message list and marks each message as a draft.
unflag   Takes a message list and marks each message as not being flagged.
unfwdignore   Removes the header field names from the list of ignored fields for the forward command.
unfwdretain   Removes the header field names from the list of retained fields for the forward command.
ungood   Takes a message list and undoes the effect of a good command that was previously applied on exactly these messages.
unignore   Removes the header field names from the list of ignored fields.
unjunk   Takes a message list and undoes the effect of a junk command that was previously applied on exactly these messages.
unkill   Takes a message list and 'unkills' each message. Also sets the score of the messages to 0.
Unread   Same as unread.
unread U Takes a message list and marks each message as not having been read.
unretain   Removes the header field names from the list of retained fields.
unsaveignore   Removes the header field names from the list of ignored fields for saving.
unsaveretain   Removes the header field names from the list of retained fields for saving.
unset   Takes a list of option names and discards their remembered values; the inverse of set.
unshortcut   Deletes the shortcut names given as arguments.
unsort   Disable sorted or threaded mode (see the sort and thread commands), return to normal message order and, if the header variable is set, print a header summary.
unthread unth Same as unsort.
verify verif Takes a message list and verifies each message. If a message is not an S/MIME signed message, verification will fail for it. The verification process checks if the message was signed using a valid certificate, if the message sender's email address matches one of those contained within the certificate, and if the message content has been altered.
visual v Takes a message list and invokes the display editor on each message. Modified contents are discarded unless the writebackedited variable is set.
write w For conventional messages, the body without all headers is written. The output is decrypted and converted to its native format, if necessary. If the output file exists, the text is appended. If a message is in MIME multipart format, its first part is written to the specified file as for conventional messages, and the user is asked for a filename to save each other part; if the contents of the first part are not to be saved, 'write /dev/null' can be used. For the second and subsequent parts, if the filename given starts with a '|' character, the part is piped through the remainder of the filename interpreted as a shell command. In non-interactive mode, only the parts of the multipart message that have a filename given in the part header are written; the others are discarded. The original message is never marked for deletion in the originating mail folder. For attachments, the contents of the destination file are overwritten if the file previously existed. No special handling of compressed files is performed.
xit x A synonym for exit.
z   Mailx presents message headers in windowfuls as described under the headers command. The z command scrolls to the next window of messages. If an argument is given, it specifies the window to use. A number prefixed by '+' or '-' indicates that the window is calculated in relation to the current position. A number without a prefix specifies an absolute window number, and a '$' lets mailx scroll to the last window of messages.
Z   Similar to z, but scrolls to the next or previous window that contains at least one new or 'flagged' message.

Tilde Escapes

"Tilde Escapes" are characters which are given a special command behavior when a tilde (the ~ character) is placed in front of them, at the beginning of a new line. The following tilde escapes are recognized by mailx:

~!command Execute the indicated shell command, then return to the message.
~. Same effect as typing the end-of-file character.
~<filename Identical to ~r.
~<!command command is executed using the shell. Its standard output is inserted into the message.
~@ [filename . . . ] With no arguments, edit the attachment list. First, the user can edit all existing attachment data. If an attachment's file name is left empty, that attachment is deleted from the list. When the end of the attachment list is reached, mailx will ask for further attachments, until an empty file name is given. If filename arguments are specified, all of them are appended to the end of the attachment list. Filenames which contain white space can only be specified with the first method (no filename arguments).
~A Inserts the string contained in the Sign variable (same as '~i Sign'). The escape sequences '\t' (tab) and '\n' (newline) are understood.
~a Inserts the string contained in the sign variable (same as '~i sign'). The escape sequences '\t' (tab) and '\n' (newline) are understood.
~bname . . . Add the given names to the list of carbon copy recipients but do not make the names visible in the Cc: line ('blind' carbon copy).
~cname . . . Add the given names to the list of carbon copy recipients.
~d Read the file 'dead.letter' from the user's home directory into the message.
~e Invoke the text editor on the message collected so far. After the editing session is finished, the user may continue appending text to the message.
~fmessages Read the named messages into the message being sent. If no messages are specified, read in the current message. Message headers currently being ignored (by the ignore or retain command) are not included. For MIME multipart messages, only the first printable part is included.
~Fmessages Identical to ~f, except all message headers and all MIME parts are included.
~h Edit the message header fields 'To:', 'Cc:', 'Bcc:', and 'Subject:' by typing each one in turn and allowing the user to append text to the end or modify the field by using the current terminal erase and kill characters.
~H Edit the message header fields 'From:', 'Reply-To:', 'Sender:', and 'Organization:' in the same manner as described for ~h. The default values for these fields originate from the from, replyto, and ORGANIZATION variables. If this tilde command has been used, changing the variables has no effect on the current message anymore.
~ivariable Insert the value of the specified variable into the message adding a newline character at the end. If the variable is unset or empty, the message remains unaltered. The escape sequences '\t' (tab) and '\n' (newline) are understood.
~mmessages Read the named messages into the message being sent, indented by a tab or by the value of indentprefix. If no messages are specified, read the current message. Message headers currently being ignored (by the ignore or retain command) are not included. For MIME multipart messages, only the first printable part is included.
~Mmessages Identical to ~m, except all message headers and all MIME parts are included.
~p Print out the message collected so far, prefaced by the message header fields and followed by the attachment list, if any. If the message text is longer than the screen size, it is piped through the pager.
~q Abort the message being sent, copying the message to 'dead.letter' in the user's home directory if save is set.
~rfilename Read the named file into the message.
~sstring Cause the named string to become the current subject field.
~tname . . . Add the given names to the direct recipient list.
~v Invoke an alternate editor (defined by the VISUAL option) on the message collected so far. Usually, the alternate editor will be a screen editor. After the editor is quit, the user may resume appending text to the end of the message.
~wfilename Write the message onto the named file. If the file exists, the message is appended to it.
~x Same as ~q, except that the message is not saved to the 'dead.letter' file.
~|command Pipe the message through the command as a filter. If the command gives no output or terminates abnormally, retain the original text of the message. The command fmt is often used as command to rejustify the message.
~:mailx-command Execute the given mailx command. Not all commands, however, are allowed.
~_mailx-command Identical to ~:.
~~string Insert the string of text in the message prefaced by a single ~. If the escape character has been changed, that character must be doubled in order to send it at the beginning of a line.

Variable Options

Variable Options are controlled via set and unset commands; see their entries for a syntax description. An option is also set if it is passed to mailx as part of the environment (this is not restricted to specific variables as in the POSIX standard). A value given in a startup file overrides a value imported from the environment. Options may be either binary, in which case it is only significant to see whether they are set or not; or string, in which case the actual value is of interest.

Binary Options

The binary options include the following:

allnet Causes only the local part to be evaluated when comparing addresses.
append Causes messages saved in mbox to be appended to the end rather than prepended. This should always be set.
ask, asksub Causes mailx to prompt for the subject of each message sent. If the user responds with simply a newline, no subject field will be sent.
askatend Causes the prompts for 'Cc:' and 'Bcc:' lists to appear after the message has been edited.
askattach If set, mailx asks for files to attach at the end of each message. Responding with a newline indicates not to include an attachment.
askcc Causes the user to be prompted for additional carbon copy recipients (at the end of each message if askatend or bsdcompat is set). Responding with a newline indicates the user's satisfaction with the current list.
askbcc Causes the user to be prompted for additional blind carbon copy recipients (at the end of each message if askatend or bsdcompat is set). Responding with a newline indicates the user's satisfaction with the current list.
asksign Causes the user to be prompted if the message is to be signed at the end of each message. The smime-sign variable is ignored when this variable is set.
autocollapse Causes threads to be collapsed automatically when threaded mode is entered (see the collapse command).
autoinc Same as newmail.
autoprint Causes the delete command to behave like dp; thus, after deleting a message, the next one will be typed automatically.
autothread Causes threaded mode (see the thread command) to be entered automatically when a folder is opened.
bang Enables the substitution of '!' by the contents of the last command line in shell escapes.
bsdannounce Causes automatic display of a header summary after executing a folder command.
bsdcompat Sets some cosmetical features to traditional BSD style; has the same affect as setting 'askatend' and all other variables prefixed with 'bsd', setting prompt to '& ', and changing the default pager to more.
bsdflags Changes the letters printed in the first column of a header summary to traditional BSD style.
bsdheadline Changes the display of columns in a header summary to traditional BSD style.
bsdmsgs Changes some informational messages to traditional BSD style.
bsdorder Causes the 'Subject:' field to appear immediately after the 'To:' field in message headers and with the ~h tilde command.
bsdset Changes the output format of the set command to traditional BSD style.
chained-junk-tokens Normally, the Bayesian junk mail filter bases its classifications on single word tokens extracted from messages. If this option is set, adjacent words are combined to pairs, which are then used as additional tokens. This usually improves the accuracy of the filter, but also increases the junk mail database five-to-tenfold.
datefield The date in a header summary is normally the date of the mailbox 'From ' line of the message. If this variable is set, the date as given in the 'Date:' header field is used, converted to local time.
debug Prints debugging messages and disables the actual delivery of messages. Unlike verbose, this option is intended for mailx development only.
disconnected When an IMAP mailbox is selected and this variable is set, no connection to the server is initiated. Instead, data is obtained from the local cache (see imap-cache). Mailboxes that are not present in the cache and messages that have not yet entirely been fetched from the server are not available; to fetch all messages in a mailbox at once, the command 'copy * /dev/null' can be used while still in online mode. Changes that are made to IMAP mailboxes in disconnected mode are queued and committed later when a connection to that server is opened in online mode. This procedure is not completely reliable since it cannot be guaranteed that the IMAP unique identifiers (UIDs) on the server still match the ones in the cache at that time. Data is saved to 'dead.letter' when this problem occurs.
disconnected-user@host The specified account is handled as described for the disconnected variable above, but other accounts are not affected.
dot The binary option dot causes mailx to interpret a period alone on a line as the terminator of a message the user is sending.
editheaders When a message is edited while being composed, its header is included in the editable text. 'To:', 'Cc:', 'Bcc:', 'Subject:', 'From:', 'Reply-To:', 'Sender:', and 'Organization:' fields are accepted within the header, other fields are ignored.
emptybox If set, an empty mailbox file is not removed. This may improve the interoperability with other mail user agents when using a common folder directory.
emptystart If the mailbox is empty, mailx normally prints 'No mail for user' and exits immediately. If this option is set, mailx starts even if the mailbox is empty.
flipr Exchanges the Respond with the respond commands and vice-versa.
forward-as-attachment Original messages are normally sent as inline text with the forward command, and only the first part of a multipart message is included. With this option, messages are sent as MIME message/rfc822 attachments, and all of their parts are included. The fwdignore and fwdretain options are ignored when the forward-as-attachment option is set.
fullnames When replying to a message, mailx normally removes the comment parts of email addresses, which by convention contain the full names of the recipients. If this variable is set, such stripping is not performed, and comments are retained.
header Causes the header summary to be written at startup and after commands that affect the number of messages or the order of messages in the current folder; enabled by default.
hold This option is used to hold messages in the system mailbox by default.
ignore Causes interrupt signals from the terminal to be ignored and echoed as @'s.
ignoreeof An option related to dot is ignoreeof which makes mailx refuse to accept a control-d as the end of a message. Ignoreeof also applies to mailx command mode.
imap-use-starttls Causes mailx to issue a STARTTLS command to make an unencrypted IMAP session SSL/TLS encrypted. This functionality is not supported by all servers, and is not used if the session is already encrypted by the IMAPS method.
imap-use-starttls-user@host Activates imap-use-starttls for a specific account.
keep This option causes mailx to truncate the user's system mailbox instead of deleting it when it is empty. This should always be set, since it prevents malicious users from creating fake mail folders in a world-writable spool directory.
keepsave When a message is saved, it is usually discarded from the originating folder when mailx is quit. Setting this option causes all saved message to be retained.
markanswered When a message is replied to and this variable is set, it is marked as having been answered. This mark has no technical meaning in the mail system; it just causes messages to be marked in the header summary, and makes them specially addressable.
metoo Usually, when a group is expanded that contains the sender, the sender is removed from the expansion. Setting this option causes the sender to be included in the group.
newmail Checks for new mail in the current folder each time the prompt is printed. For IMAP mailboxes, the server is then polled for new mail, which may result in delayed operation if the connection to the server is slow. A maildir folder must be re-scanned to determine if new mail has arrived.

If this variable is set to the special value nopoll, an IMAP server is not actively asked for new mail, but new mail may still be detected and announced with any other IMAP command that is sent to the server. A maildir folder is not scanned then.

In any case, the IMAP server may send notifications about messages that have been deleted on the server by another process or client. In this case, 'Expunged n messages' is printed regardless of this variable, and message numbers may have changed.
noheader Setting the option noheader is the same as giving the -N flag on the command line.
outfolder Causes the filename given in the record variable and the sender-based filenames for the Copy and Save commands to be interpreted relative to the directory given in the folder variable rather than to the current directory unless it is an absolute pathname.
page If set, each message the pipe command prints out is followed by a formfeed character.
piperaw Send messages to the pipe command without performing MIME and character set conversions.
pop3-use-apop If this variable is set, the APOP authentication method is used when a connection to a POP3 server is initiated. The advantage of this method over the usual USER/PASS authentication is that the password is not sent over the network in clear text. The connection fails if the server does not support the APOP command.
pop3-use-apop-user@host Enables pop3-use-apop for a specific account.
pop3-use-starttls Causes mailx to issue a STLS command to make an unencrypted POP3 session SSL/TLS encrypted. This functionality is not supported by all servers, and is not used if the session is already encrypted by the POP3S method.
pop3-use-starttls-user@host Activates pop3-use-starttls for a specific account.
print-all-chars This option causes all characters to be considered printable. It is only effective if given in a startup file. With this option set, some character sequences in messages may put the user's terminal in an undefined state when printed; it should only be used as a last resort if no working system locale can be found.
print-alternatives When a MIME message part of type "multipart/alternative" is displayed and it contains a subpart of type "text/plain", other parts are normally discarded. Setting this variable causes all subparts to be displayed, just as if the surrounding part was of type "multipart/mixed".
quiet Suppresses the printing of the version when first invoked.
record-resent If both this variable and the record variable are set, the resend and Resend commands save messages to the record folder as it is normally only done for newly composed messages.
reply-in-same-charset If this variable is set, mailx first tries to use the same character set of the original message for replies. If this fails, the sendcharsets variable is evaluated as usual.
Replyall Reverses the sense of reply and Reply commands.
save When the user aborts a message with two RUBOUT (interrupt) characters, mailx copies the partial letter to the file 'dead.letter' in the home directory. This option is set by default.
searchheaders If this option is set, then a message-list specifier in the form '/x:y' will expand to all messages containing the substring 'y' in the header field 'x'. The string search is case insensitive.
sendwait When sending a message, wait until the mail transfer agent exits before accepting further commands. If the mail transfer agent returns a non-zero exit status, the exit status of mailx will also be non-zero.
showlast Setting this option causes mailx to start at the last message instead of the first one when opening a mail folder.
showname Causes mailx to use the sender's real name instead of the plain address in the header field summary and in message specifications.
showto Causes the recipient of the message to be shown in the header summary if the message was sent by the user.
skipemptybody If an outgoing message does not contain any text in its first or only message part, do not send it but discard it silently (see also the -E option).
smime-force-encryption Causes mailx to refuse sending unencrypted messages.
smime-sign If this variable is set, outgoing messages are S/MIME signed with the user's private key. Signing a message enables a recipient to verify that the sender used a valid certificate, that the email addresses in the certificate match those in the message header, and that the message content has not been altered. It does not change the message text, and people will be able to read the message as usual.
smime-no-default-ca Do not load the default CA locations when verifying S/MIME signed messages. Only applicable if S/MIME support is built using OpenSSL.
smtp-use-starttls Causes mailx to issue a STARTTLS command to make an SMTP session SSL/TLS encrypted. Not all servers support this command; because of common implementation defects, it cannot be automatically determined whether a server supports it or not.
ssl-no-default-ca Do not load the default CA locations to verify SSL/TLS server certificates. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-v2-allow Accept SSLv2 connections. These are normally not allowed because this protocol version is insecure.
stealthmua Inhibits the generation of the 'Message-Id:' and 'User-Agent:' header fields that include obvious references to mailx. There are two pitfalls associated with this: First, the message id of outgoing messages is not known anymore. Second, an expert may still use the remaining information in the header to track down the originating mail user agent.
verbose Setting the option verbose is the same as using the -v flag on the command line. When mailx runs in verbose mode, details of the actual message delivery and protocol conversations for IMAP, POP3, and SMTP, as well as of other internal processes, are displayed on the user's terminal, This is sometimes useful to debug problems. Mailx prints all data that is sent to remote servers in clear texts, including passwords, so care should be taken that no unauthorized option can view the screen if this option is enabled.
writebackedited If this variable is set, messages modified using the edit or visual commands are written back to the current folder when it is quit. This is only possible for writable folders in mbox format. Setting this variable also disables MIME decoding and decryption for the editing commands.

String Options

The string options include the following:

attrlist A sequence of characters to print in the 'attribute' column of a header summary, each for one type of messages in the following order:
  • new
  • unread but old
  • new but read
  • read and old
  • saved
  • preserved
  • mboxed
  • flagged
  • answered
  • draft
  • killed
  • start of a collapsed thread
  • collapsed
  • classified as junk
The default is 'NUROSPMFATK+-J', or 'NU *HMFATK+-J' if bsdflags or the SYSV3 environment variable are set.
autobcc Specifies a list of recipients to which a blind carbon copy of each outgoing message will be sent automatically.
autocc Specifies a list of recipients to which a carbon copy of each outgoing message will be sent automatically.
autosort Causes sorted mode (see the sort command) to be entered automatically with the value of this option as sorting method when a folder is opened.
cmd The default value for the pipe command.
crt The valued option crt is used as a threshold to determine how long a message must be before PAGER is used to read it. If crt is set without a value, then the height of the terminal screen stored in the system is used to compute the threshold (see stty).
DEAD The name of the file to use for saving aborted messages. This defaults to 'dead.letter' in the user's home directory.
EDITOR Pathname of the text editor to use in the edit command and ~e escape. If not defined, then a default editor is used.
encoding The default MIME encoding to use in outgoing text messages and message parts. Valid values are 8bit or quoted-printable. The default is 8bit. In case the mail transfer system is not ESMTP compliant, quoted-printable should be used instead. If there is no need to encode a message, 7bit transfer mode is used, without regard to the value of this variable. Binary data is always encoded in base64 mode.
escape If defined, the first character of this option gives the character to use in the place of ~ to denote escapes.
folder The name of the directory to use for storing folders of messages. All folder names that begin with '+' refer to files below that directory. If the directory name begins with a '/', mailx considers it to be an absolute pathname; otherwise, the folder directory is found relative to the user's home directory.

The directory name may also refer to an IMAP account; any names that begin with '+' then refer to IMAP mailboxes on that account. An IMAP folder is normally given in the form

imaps://mylogin@imap.myisp.example 
In this case, the '+' and '@' prefixes for folder names have the same effect (see the folder command).

Some IMAP servers do not accept the creation of mailboxes in the hierarchy base; they require that they are created as subfolders of 'INBOX'. With such servers, a folder name of the form

imaps://mylogin@imap.myisp.example/INBOX. 
should be used (the last character is the server's hierarchy delimiter). Folder names prefixed by '+' will then refer to folders below 'INBOX', while folder names prefixed by '@' refer to folders below the hierarchy base. See the imap namespace command for a method to detect the appropriate prefix and delimiter.
folder-hook When a folder is opened and this variable is set, the macro corresponding to the value of this variable is executed. The macro is also invoked when new mail arrives, but message lists for commands executed from the macro only include newly arrived messages in that case.
folder-hook-fullname When a folder named fullname is opened, the macro corresponding to the value of this variable is executed. Unlike other folder specifications, the fully expanded name of a folder, without metacharacters, is used to avoid ambiguities. The macro specified with folder-hook is not executed if this variable is effective for a folder (unless it is explicitly invoked within the called macro).
from The address (or a list of addresses) to put into the 'From:' field of the message header. If replying to a message, these addresses are handled as if they were in the alternates list. If the machine's hostname is not valid at the Internet (for example at a dialup machine), either this variable or hostname have to be set to get correct Message-ID header fields. If from contains more than one address, the sender variable must also be set.
fwdheading The string to print before the text of a message with the forward command (unless the forward-as-attachment variable is set). Defaults to ''-------- Original Message --------'' if unset. If it is set to the empty string, no heading is printed.
headline A format string to use for the header summary, similar to printf formats. A '%' character introduces a format specifier. It may be followed by a number indicating the field width. If the field is a number, the width may be negative, which indicates that it is to be left-aligned. Valid format specifiers are: '%>%a%m %18f %16d %4l/%-5o %i%s' (default), or '%>%a%m %20f %16d %3l/%-5o %i%S' (if bsdcompat is set).
hostname Use this string as hostname when expanding local addresses instead of the value obtained from uname and getaddrinfo.
imap-auth Sets the IMAP authentication method. Valid values are 'login' for the usual password-based authentication (the default), 'cram-md5', which is a password-based authentication that does not send the password over the network in clear text, and 'gssapi' for GSSAPI-based authentication.
imap-auth-user@host Sets the IMAP authentication method for a specific account.
imap-cache Enables caching of IMAP mailboxes. The value of this variable must point to a directory that is either existent or can be created by mailx. All contents of the cache can be deleted by mailx at any time; it is not safe to make assumptions about them.
imap-keepalive IMAP servers may close the connection after a period of inactivity; the standard requires this to be at least 30 minutes, but practical experience may vary. Setting this variable to a numeric value greater than 0 causes a NOOP command to be sent each value seconds if no other operation is performed.
imap-list-depth When retrieving the list of folders on an IMAP server, the folders command stops after it has reached a certain depth to avoid possible infinite loops. The value of this variable sets the maximum depth allowed. The default is 2. If the folder separator on the current IMAP server is a slash '/', this variable has no effect, and the folders command does not descend to subfolders.
indentprefix String used by the '~m' and '~M' tilde escapes and by the quote option for indenting messages, in place of the normal tab character (^I). Be sure to quote the value if it contains spaces or tabs.
junkdb The location of the junk mail database. The string is treated like a folder name, as described for the folder command.

The files in the junk mail database are normally stored in compress format for saving space. If processing time is considered more important, uncompress can be used to store them in plain form. Mailx will then work using the uncompressed files.
LISTER Pathname of the directory lister to use in the folders command when operating on local mailboxes. Default is /bin/ls.
MAIL Is used as the user's mailbox, if set. Otherwise, a system-dependent default is used. Can be a protocol:// string (see the folder command for more information).
MAILX_HEAD A string to put at the beginning of each new message. The escape sequences '\t' (tab) and '\n' (newline) are understood.
MAILX_TAIL A string to put at the end of each new message. The escape sequences '\t' (tab) and '\n' (newline) are understood.
maximum-unencoded-line-length Messages that contain lines longer than the value of this variable are encoded in quoted-printable even if they contain only ASCII characters. The maximum effective value is 950. If set to 0, all ASCII text messages are encoded in quoted-printable. S/MIME signed messages are always encoded in quoted-printable regardless of the value of this variable.
MBOX The name of the mbox file. It can be the name of a folder. The default is 'mbox' in the user's home directory.
NAIL_EXTRA_RC The name of an optional startup file to be read after ~/.mailrc. This variable is ignored if it is imported from the environment; it has an effect only if it is set in /etc/mail.rc or ~/.mailrc to allow bypassing the configuration with, e.g., 'MAILRC=/dev/null'. Use this file for commands that are not understood by other mailx implementations.
newfolders If this variable has the value maildir, newly created local folders will be in maildir format.
nss-config-dir A directory that contains the files certN.db to retrieve certificates, keyN.db to retrieve private keys, and secmod.db, where N is a digit. These are usually taken from Mozilla installations, so an appropriate value might be '~/.mozilla/firefox/default.clm'. Mailx opens these files read-only and does not modify them. However, if the files are modified by Mozilla while mailx is running, it will print a 'Bad database' message. It may be necessary to create copies of these files that are exclusively used by mailx then. Only applicable if S/MIME and SSL/TLS support is built using Network Security Services (NSS).
ORGANIZATION The value to put into the 'Organization:' field of the message header.
PAGER Pathname of the program to use in the more command or when crt variable is set. The default paginator pg or, in BSD compatibility mode, more is used if this option is not defined.
password-user@host Set the password for user when connecting to host. If no such variable is defined for a host, the user will be asked for a password on standard input. Specifying passwords in a startup file is generally a security risk, the file should be readable by the invoking user only.
pipe-content/subcontent When a MIME message part of content/subcontent type is displayed or it is replied to, its text is filtered through the value of this variable interpreted as a shell command. Special care must be taken when using such commands as mail viruses may be distributed by this method; if messages of type application/x-sh were filtered through the shell, for example, a message sender could easily execute arbitrary code on the system mailx is running on.
pop3-keepalive POP3 servers may close the connection after a period of inactivity; the standard requires this to be at least 10 minutes, but practical experience may vary. Setting this variable to a numeric value greater than 0 causes a NOOP command to be sent each value seconds if no other operation is performed.
prompt The string printed when a command is accepted. Defaults to '? ', or to '& ' if the bsdcompat variable is set.
quote If set, mailx starts a replying message with the original message prefixed by the value of the variable indentprefix. Normally, a heading consisting of 'Fromheaderfield wrote:' is printed before the quotation. If the string noheading is assigned to the quote variable, this heading is omitted. If the string headers is assigned, the headers selected by the ignore/retain commands are printed above the message body, thus quote acts like an automatic ~m command in that case. If the string allheaders is assigned, all headers are printed above the message body, and all MIME parts are included, thus quote acts like an automatic ~M command in that case.
record If defined, gives the pathname of the folder used to record all outgoing mail. If not defined, then outgoing mail is not so saved. When saving to this folder fails, the message is not sent but saved to the 'dead.letter' file instead.
replyto A list of addresses to put into the 'Reply-To:' field of the message header. If replying to a message, such addresses are handled as if they were in the alternates list.
screen When mailx initially prints the message headers, it determines the number to print by looking at the speed of the terminal. The faster the terminal, the more it prints. This option overrides this calculation and specifies how many message headers are printed. This number is also used for scrolling with the z command.
sendcharsets A comma-separated list of character set names that can be used in Internet mail. When a message that contains characters not representable in US-ASCII is prepared for sending, mailx tries to convert its text to each of the given character sets in order and uses the first appropriate one. The default is 'utf-8'.

Character sets assigned to this variable should be ordered in ascending complexity. That is, the list should start with e.g. 'iso-8859-1' for compatibility with older mail clients, might contain some other language-specific character sets, and should end with 'utf-8' to handle messages that combine texts in multiple languages.
sender An address that is put into the 'Sender:' field of outgoing messages. This field needs not normally be present. It is, however, required if the 'From:' field contains more than one address. It can also be used to indicate that a message was sent on behalf of somebody other; in this case, 'From:' should contain the address of the person that took responsibility for the message, and 'Sender:' should contain the address of the person that actually sent the message. The sender address is handled as if it were in the alternates list.
sendmail To use an alternate mail delivery system, set this option to the full pathname of the program to use. This should be used with care.
SHELL Pathname of the shell to use in the ! command and the ~! escape. A default shell is used if this option is not defined.
Sign A string for use with the ~A command.
sign A string for use with the ~a command.
signature Must correspond to the name of a readable file if set. The file's content is then appended to each singlepart message and to the first part of each multipart message. Be warned that there is no possibility to edit the signature for an individual message.
smime-ca-dir Specifies a directory with CA certificates for verification of S/MIME signed messages. The format is the same as described in ssl_ctx_load_verify_locations. Only applicable if S/MIME support is built using OpenSSL.
smime-ca-file Specifies a file with CA certificates for verification of S/MIME signed messages. The format is the same as described in ssl_ctx_load_verify_locations. Only applicable if S/MIME support is built using OpenSSL.
smime-cipher-user@host Specifies a cipher to use when generating S/MIME encrypted messages for user@host. Valid ciphers are rc2-40 (RC2 with 40 bits), rc2-64 (RC2 with 64 bits), des (DES, 56 bits) and des-ede3 (3DES, 112/168 bits). The default is 3DES. It is not recommended to use the other ciphers unless a recipient's client is actually unable to handle 3DES since they are comparatively weak; but even so, the recipient should upgrade his software in preference.
smime-crl-file Specifies a file that contains a CRL in PEM format to use when verifying S/MIME messages. Only applicable if S/MIME support is built using OpenSSL.
smime-crl-dir Specifies a directory that contains files with CRLs in PEM format to use when verifying S/MIME messages. Only applicable if S/MIME support is built using OpenSSL.
smime-encrypt-user@host If this variable is set, messages to user@host are encrypted before sending. If S/MIME support is built using OpenSSL, the value of the variable must be set to the name of a file that contains a certificate in PEM format. If S/MIME support is built using NSS, the value of this variable is ignored, but if multiple certificates for user@host are available, the smime-nickname-user@host variable should be set. Otherwise a certificate for the recipient is automatically retrieved from the certificate database, if possible.

If a message is sent to multiple recipients, each of them for whom a corresponding variable is set will receive an individually encrypted message; other recipients will continue to receive the message in plain text unless the smime-force-encryption variable is set. It is recommended to sign encrypted messages, i.e. to also set the smime-sign variable.
smime-nickname-user@host Specifies the nickname of a certificate to be used when encrypting messages for user@host. Only applicable if S/MIME support is built using NSS.
smime-sign-cert Points to a file in PEM format that contains the user's private key as well as his certificate. Both are used with S/MIME for signing and decrypting messages. Only applicable if S/MIME support is built using OpenSSL.
smime-sign-cert-user@host Overrides smime-sign-cert for the specific addresses. When signing messages and the value of the from variable is set to user@host, the specific file is used. When decrypting messages, their recipient fields (To: and Cc:) are searched for addresses for which such a variable is set. Mailx always uses the first address that matches, so if the same message is sent to more than one of the user's addresses using different encryption keys, decryption might fail. Only applicable if S/MIME support is built using OpenSSL.
smime-sign-nickname Specifies that the named certificate be used for signing mail. If this variable is not set, but a single certificate matching the current from address is found in the database, that one is used automatically. Only applicable if S/MIME support is built using NSS.
smime-sign-nickname-user@host Overrides smime-sign-nickname for a specific address. Only applicable if S/MIME support is built using NSS.
smtp Normally, mailx invokes sendmail directly to transfer messages. If the smtp variable is set, a SMTP connection to the server specified by the value of this variable is used instead. If the SMTP server does not use the standard port, a value of server:port can be given, with port as a name or as a number.

There are two possible methods to get SSL/TLS encrypted SMTP sessions: First, the STARTTLS command can be used to encrypt a session after it has been initiated, but before any user-related data has been sent; see smtp-use-starttls above. Second, some servers accept sessions that are encrypted from their beginning on. This mode is configured by assigning smtps://server[:port] to the smtp variable.

The SMTP transfer is executed in a child process; unless either the sendwait or the verbose variable is set, this process runs asynchronously. If it receives a TERM signal, it will abort and save the message to the 'dead.letter' file.
smtp-auth Sets the SMTP authentication method. If set to 'login', or if unset and smtp-auth-user is set, AUTH LOGIN is used. If set to 'cram-md5', AUTH CRAM-MD5 is used; if set to 'plain', AUTH PLAIN is used. Otherwise, no SMTP authentication is performed.
smtp-auth-user@host Overrides smtp-auth for specific values of sender addresses, depending on the from variable.
smtp-auth-password Sets the global password for SMTP AUTH. Both user and password have to be given for AUTH LOGIN and AUTH CRAM-MD5.
smtp-auth-password-user@host Overrides smtp-auth-password for specific values of sender addresses, depending on the from variable.
smtp-auth-user Sets the global user name for SMTP AUTH. Both user and password have to be given for AUTH LOGIN and AUTH CRAM-MD5.

If this variable is set but neither smtp-auth-password or a matching smtp-auth-password-user@host can be found, mailx will as for a password on the user's terminal.
smtp-auth-user-user@host Overrides smtp-auth-user for specific values of sender addresses, depending on the from variable.
ssl-ca-dir Specifies a directory with CA certificates for verification of SSL/TLS server certificates. See ssl_ctx_load_verify_locations for more information. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-ca-file Specifies a file with CA certificates for verification of SSL/TLS server certificates. See ssl_ctx_load_verify_locations for more information. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-cert Sets the file name for a SSL/TLS client certificate required by some servers. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-cert-user@host Sets an account-specific file name for a SSL/TLS client certificate required by some servers. Overrides ssl-cert for the specified account. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-cipher-list Specifies a list of ciphers for SSL/TLS connections. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-crl-file Specifies a file that contains a CRL in PEM format to use when verifying SSL/TLS server certificates. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-crl-dir Specifies a directory that contains files with CRLs in PEM format to use when verifying SSL/TLS server certificates. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-key Sets the file name for the private key of a SSL/TLS client certificate. If unset, the name of the certificate file is used. The file is expected to be in PEM format. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-key-user@host Sets an account-specific file name for the private key of a SSL/TLS client certificate. Overrides ssl-key for the specified account. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-method Selects a SSL/TLS protocol version; valid values are 'ssl2', 'ssl3', and 'tls1'. If unset, the method is selected automatically, if possible.
ssl-method-user@host Overrides ssl-method for a specific account.
ssl-rand-egd Gives the pathname to an entropy daemon socket, see rand_egd.
ssl-rand-file Gives the pathname to a file with entropy data, see rand_load_file. If the file is a regular file writable by the invoking user, new data is written to it after it has been loaded. Only applicable if SSL/TLS support is built using OpenSSL.
ssl-verify Sets the action to be performed if an error occurs during SSL/TLS server certificate validation. Valid values are 'strict' (fail and close connection immediately), 'ask' (ask whether to continue on standard input), 'warn' (print a warning and continue), 'ignore' (do not perform validation). The default is 'ask'.
ssl-verify-user@host Overrides ssl-verify for a specific account.
toplines If defined, gives the number of lines of a message to be printed out with the top command; normally, the first five lines are printed.
ttycharset The character set of the terminal mailx operates on. There is normally no need to set this variable since mailx can determine this automatically by looking at the LC_CTYPE locale setting; if this succeeds, the value is assigned at startup and will be displayed by the set command. Note that this is not necessarily a character set name that can be used in Internet messages.
VISUAL Pathname of the text editor to use in the visual command and ~v escape.

Environment Variables

Besides the variables described above, mailx uses the following environment strings:

HOME The user's home directory.
LANG, LC_ALL, LC_COLLATE, LC_CTYPE, LC_MESSAGES See locale.
MAILRC Is used as startup file instead of ~/.mailrc if set. When mailx scripts are invoked on behalf of other users, this variable should be set to '/dev/null' to avoid side-effects from reading their configuration files.
NAILRC If this variable is set and MAILRC is not set, it is read as startup file.
SYSV3 Changes the letters printed in the first column of a header summary.
TMPDIR Used as directory for temporary files instead of /tmp, if set.

Files

~/.mailrc File giving initial commands.
/etc/mail.rc System wide initialization file.
~/.mime.types Personal MIME types.
/etc/mime.types System wide MIME types.

Examples

The mailx command has two distinct usages, according to whether one wants to send or receive mail. Sending mail is simple: to send a message to a user whose email address is, say, bill@example.com, use the shell command

mailx bill@example.com 

and then type your message. Mailx will prompt you for a message subject first; after that, lines typed by you form the body of the message. When you reach the end of the message, type an End Of Transmission character (control-d) at the beginning of a line, which will cause mailx to echo 'EOT' and return you to the shell.

If, while you are composing the message you decide that you do not wish to send it after all, you can abort the letter with a RUBOUT (control-c). Typing a single RUBOUT causes mailx to print '(Interrupt -- one more to kill letter)'. Typing a second RUBOUT causes mailx to save your partial letter on the file 'dead.letter' in your home directory and abort the letter. Once you have sent mail to someone, there is no way to undo the send.

If you want to send the same message to several other people, you can list their email addresses on the command line, like this:

mailx sam@example.com bob@server.name 

will send the reminder to sam@example.com and bob@server.name.

To read your mail, at the command line, simply enter:

mailx 

Mailx will respond by typing its version number and date and then listing the messages you have waiting. Then it will type a prompt and await your command. The messages are assigned numbers starting with 1, and later you will refer to the messages with these numbers. Mailx keeps track of which messages are new (have been sent since you last read your mail) and read (have been read by you). New messages have an N next to them in the header listing and old, but unread messages have a U next to them. Mailx keeps track of new/old and read/unread messages by putting a header field called Status into your messages.

To look at a specific message, use the type command, which may be abbreviated to simply t. For example, if you had the following messages:

O 1 drfoo@myhost.example Wed Sep 1 19:52 18/631 "Fees" 
O 2 sam@friends.example Thu Sep 2 00:08 30/895

you could examine the first message by giving mailx the command:

type 1

which might cause it to respond with, for example:

Message 1:
From drfoo@myhost.example Wed Sep  1 19:52:25 2004
Subject: Fees
Status: R

Tuition fees are due next Wednesday. Don't forget!

Many mailx commands that operate on messages take a message number as an argument like the type command. For these commands, there is a notion of a current message. When you enter the mailx program, the current message is initially the first (or the first recent) one. Thus, you can often omit the message number and use, for example,

t 

to type the current message. As a further shorthand, you can type a message by simply giving its message number. Hence,

1 

would type the first message.

Frequently, it is useful to read the messages in your mailbox in order, one after another. You can read the next message in mailx by simply typing a newline. As a special case, you can type a newline as your first command to mailx to type the first message.

If, after typing a message, you want to immediately send a reply, you can do so with the reply command. This command, like type, takes a message number as an argument. mailx then begins a message addressed to the user who sent you the message. You may then type in your letter in reply, followed by control-d at the beginning of a line, as before.

Note that mailx copies the subject header from the original message. This is useful in that correspondence about a particular matter will tend to retain the same subject heading, making it easy to recognize. If there are other header fields in the message, like 'Cc:', the information found will also be used.

Sometimes you will receive a message that has been sent to several people and wish to reply only to the person who sent it. Reply with a capital R replies to a message, but sends a copy to the sender only.

If you want, while reading your mail, to send a message to someone, but not as a reply to one of your messages, you can send the message directly with the mail command, which takes as arguments the names of the recipients you want to send to. For example, to send a message to frank@machine.example, you enter the following from within mailx:

mail frank@machine.example 

To delete a message from the mail folder, you can use the delete command. In addition to not saving deleted messages, mailx will not let you type them, either. The effect is to make the message disappear altogether, along with its number.

Many features of mailx can be tailored to your liking with the set command. The set command has two forms, depending on whether you are setting a binary option or a valued option. Binary options are either on or off. For example, the askcc option informs mailx that each time you send a message, you want it to prompt you for a 'Cc:' header, to be included in the message. To set the askcc option, you would type

set askcc 

Valued options are values which mailx uses to adapt to your tastes. For example, the record option tells mailx where to save messages sent by you, and is specified by

set record=Sent 

for example. Note that no spaces are allowed in record=Sent.

Mailx includes a simple facility for maintaining groups of messages together in folders. To use the folder facility, you must tell mailx where you want to keep your folders. Each folder of messages will be a single file. For convenience, all of your folders are kept in a single directory of your choosing. To tell mailx where your folder directory is, put a line of the form

set folder=letters 

in your .mailrc file. If, as in the example above, your folder directory does not begin with a '/', mailx will assume that your folder directory is to be found starting from your home directory.

Anywhere a file name is expected, you can use a folder name, preceded with '+'. For example, to put a message into a folder with the save command, you can use:

save +classwork 

to save the current message in the classwork folder. If the classwork folder does not yet exist, it will be created. Note that messages which are saved with the save command are automatically removed from your system mailbox.

In order to make a copy of a message in a folder without causing that message to be removed from your system mailbox, use the copy command, which is identical in all other respects to the save command.

The folder command can be used to direct mailx to the contents of a different folder. For example,

folder +classwork 

directs mailx to read the contents of the classwork folder. All of the commands that you can use on your system mailbox are also applicable to folders, including type, delete, and reply. To inquire which folder you are currently editing, use simply:

folder

To list your current set of folders, use the folders command.

Finally, the help command is available to print out a brief summary of the most important mailx commands.

While typing in a message to be sent to others, it is often useful to be able to invoke the text editor on the partial message, print the message, execute a shell command, or do some other auxiliary function. Mailx provides these capabilities through tilde escapes, which consist of a tilde (~) at the beginning of a line, followed by a single character which indicates the function to be performed. For example, to print the text of the message so far, use:

~p 

which will print a line of dashes, the recipients of your message, and the text of the message so far. A list of the most important tilde escapes is available by typing '~?'.

Related commands

biff — Receive detailed mail notifications at the command line.
echo — Output text.
ed — A simple text editor.
ex — Line-editor mode of the vi text editor.
fmt — A formatter for simplifying and optimizing text files.
lp — Print a file on the System V operating system.
ls — List the contents of a directory or directories.
mail — Read, compose, and manage mail.
mailcompat — Provide SunOS 4.x compatibility for the Solaris mailbox format.
more — Display text one screen at a time.
newalias — Install new elm aliases.
pg — Browse page by page through text files.
sh — The Bourne shell command interpreter.
vacation — Reply to mail automatically.
vi — Text editor based on the visual mode of ex.