At startup time, mail will execute commands in the system command file, /etc/mail.rc , unless explicitly told not to by using the -n option. Next, the commands in the user's personal command file ~/.mailrc are executed. mail then examines its command line options to determine whether the user requested a new message to be sent or existing messages in a mailbox to be examined.

To send a message to one or more people, mail can be invoked with arguments which are the names of people to whom the mail will be sent. You are then expected to type in your message, followed by a control-D at the beginning of a line. The section below, Replying to or originating mail , describes some features of mail available to help you compose your letter.

In normal usage, mail is given no arguments and checks your mail out of the post office, then prints out a one line header of each message found. The current message is initially set to the first message (numbered 1) and can be printed using the print command (which can be abbreviated p ) . Moving among the messages is much like moving between lines in ed(1) ; you may use + and - to shift forwards and backwards, or simply enter a message number to move directly.

After examining a message you can delete or reply to it. Deletion causes the mail program to forget about the message. This is not irreversible; the message can be undeleted by giving its number, or the mail session can be aborted by giving the exit command. Deleted messages, however, will usually disappear, never to be seen again.

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. The special name addresses all messages and addresses the last message; thus the command top which prints the first few lines of a message could be used in top * to print the first few lines of all messages.

You can use the reply command to set up a response to a message, sending it back to the person who it was from. Text you then type in, up to an end-of-file, defines the contents of the message. While you are composing a message, mail treats lines beginning with the tilde 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 single tab-stop (see the indentprefix variable, below). Other escapes will set up subject fields, add and delete recipients to the message, and allow you to escape to an editor to revise the message or to a shell to run some commands. (These options are given in the summary below.)

You can end a mail session with the quit command. Messages which have been examined go to your mbox 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).

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

in the file .mailrc in your home directory. The current list of such aliases can be displayed with the alias command in mail . System wide distribution lists can be created by editing /etc/aliases , (see aliases() and sendmail(8) ) ; these are kept in a different syntax. In mail you send, 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()

See mailaddr() for a description of network addresses.

mail has a number of options which can be set in the .mailrc file to alter its behavior; thus set askcc enables the askcc feature. (These options are summarized below.)

Here is a summary of the tilde escapes, which are used when composing messages to perform special functions. Tilde escapes are only recognized at the beginning of lines. The name is somewhat of a misnomer since the actual escape character can be set by the option escape .

~! Ns command

Execute the indicated shell command, then return to the message.

~b Ns name ...

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).

~c Ns name ...

Add the given names to the list of carbon copy recipients.

~d

Read the file dead.letter from your home directory into the message.

~e

Invoke the text editor on the message collected so far. After the editing session is finished, you may continue appending text to the message.

~f Ns messages

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.

~F Ns messages

Identical to ~f , except all message headers are included.

~h

Edit the message header fields 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.

~m Ns messages

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.

~M Ns messages

Identical to ~m , except all message headers are included.

~p

Print out the message collected so far, prefaced by the message header fields.

~q

Abort the message being sent, copying the message to dead.letter in your home directory if save is set.

~R Ns string

Use string as the Reply-To field.

~r Ns filename

Read the named file into the message.

~s Ns string

Cause the named string to become the current subject field.

~t Ns name ...

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 you quit the editor, you may resume appending text to the end of your message.

~w Ns filename

Write the message onto the named file.

~| Ns 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.

~: Ns mail-command

Execute the given mail command. Not all commands, however, are allowed.

~~ Ns string

Insert the string of text in the message prefaced by a single ~. If you have changed the escape character, then you should double that character in order to send it.

Options are controlled via set and unset commands. 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. The binary options include the following:

append

Causes messages saved in mbox to be appended to the end rather than prepended. This should always be set (perhaps in /etc/mail.rc ) .

ask , asksub

Causes mail to prompt you for the subject of each message you send. If you respond with simply a newline, no subject field will be sent.

askbcc

Causes you to be prompted for additional blind carbon copy recipients at the end of each message. Responding with a newline indicates your satisfaction with the current list.

askcc

Causes you to be prompted for additional carbon copy recipients at the end of each message. Responding with a newline indicates your satisfaction with the current list.

autoinc

Causes new mail to be automatically incorporated when it arrives. Setting this is similar to issuing the inc command at each prompt, except that the current message is not reset when new mail arrives.

autoprint

Causes the delete command to behave like dp ; thus, after deleting a message, the next one will be typed automatically.

debug

Setting the binary option debug is the same as specifying -d on the command line and causes mail to output all sorts of information useful for debugging mail .

dot

The binary option dot causes mail to interpret a period alone on a line as the terminator of a message you are sending.

hold

This option is used to hold messages in the system mailbox by default.

ignore

Causes interrupt signals from your terminal to be ignored and echoed as @'s.

ignoreeof

An option related to dot is ignoreeof which makes mail refuse to accept a control-D as the end of a message. ignoreeof also applies to mail command mode.

keep

Setting this option causes to truncate your system mailbox instead of deleting it when it's empty.

keepsave

Messages saved with the save command are not normally saved in mbox at quit time. Use this option to retain those messages.

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.

noheader

Setting the option noheader is the same as giving the -N flag on the command line.

nosave

Normally, when you abort a message with two interrupt characters (usually control-C), mail copies the partial letter to the file dead.letter in your home directory. Setting the binary option nosave prevents this.

Replyall

Reverses the sense of reply and Reply commands.

quiet

Suppresses the printing of the version when first invoked.

searchheaders

If this option is set, then a message-list specifier in the form will expand to all messages containing the substring in the header field The string search is case insensitive. If is omitted, it will default to the header field. The form is a special case, and will expand to all messages containing the substring in the or header fields. The check for is case sensitive, so that can be used to limit the search for to just the field.

verbose

Setting the option verbose is the same as using the -v flag on the command line. When runs in verbose mode, the actual delivery of messages is displayed on the user's terminal.

EDITOR

Pathname of the text editor to use in the edit command and ~e escape. If not defined, /usr/bin/ex is used.

LISTER

Pathname of the directory lister to use in the folders command. Default is /bin/ls .

MBOX

The name of the mbox file. It can be the name of a folder. The default is in the user's home directory.

PAGER

Pathname of the program to use in the more command or when the crt variable is set. The default paginator more() is used if this option is not defined.

REPLYTO

If set, will be used to initialize the Reply-To field for outgoing messages.

SHELL

Pathname of the shell to use in the ! command and the ~! escape. A default shell is used if this option is not defined.

VISUAL

Pathname of the text editor to use in the visual command and ~v escape. If not defined, /usr/bin/vi is used.

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(1) ) .

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. If this name begins with a mail considers it to be an absolute pathname; otherwise, the folder directory is found relative to your home directory.

indentprefix

String used by the ~m tilde escape for indenting messages, in place of the normal tab character Be sure to quote the value if it contains spaces or tabs.

record

If defined, gives the pathname of the file used to record all outgoing mail. If not defined, then outgoing mail is not so saved.

screen

Size of window of message headers for z .

sendmail

Pathname to an alternative mail delivery system.

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.