Commands directed to a mail server take the form of a mail
    message addressed to

    mailserv@mail-server-host

    where MAIL-SERVER-HOST is the host name of the machine running
    the mail server. You need to obtain this name from your system
    manager. The text of the message contains mail server commands,
    one command per line.

    For example, suppose the address of a mail server is
    mailserv@example.com. To obtain a help message from the server
    as well as a list of the available files and mailing lists, you
    would send a message much like the one shown below.

    Example 1  Sending Commands to a Mail Server

    $ MAIL
    MAIL> SEND
    To:     in%"mailserv@example.com"
    Subj:
    Enter your message below. Press CTRL/Z when complete, CTRL/C to quit:
    HELP
    INDEX
    LISTS
 <CTRL/Z>

    MAIL> EXIT
    $

    After a short while, you will receive back three messages from
    the mail server: the first message in response to the HELP
    command, the second in response to the INDEX command, and
    the third in response to the LISTS command. If your command
    specifications are in error, then the mail server will send you
    an error notification.

    Typically, mail from the mail server will have a reply address
    which differs from the address you use to send commands to
    it. This is intentional and is done to prevent potential mail
    loops. One consequence of this is that you cannot direct further
    commands to the server by replying to messages from it. You must
    always initiate a new message with the send command; you cannot
    use the reply command.

    A brief description of the available commands is given in the
    table below; complete descriptions are described under the
    "Commands" subtopic. Lines beginning with an exclamation point,
    !, are interpreted as comment lines.

    Table 2 Summary of Mail and List Server Commands

    Command          Description

    CONFIRM          Confirm a command from a previous message
    DIRECTORY        Obtain directory listing of available files
    DIRECTORY/LIST   Obtain directory listing of available mailing
                     lists
    ENCODING         Set default file transmission encoding
    END              Terminate processing, accept no additional
                     commands
    EXIT (see END)   Same as END
    FINISH (see      Same as END
    END)
    HELP             Retrieve the server-specific help information
    INDEX            Retrieve the index of available files
    LISTS            Retrieve the index of available mailing lists
    MAXIMUM          Set maximum message size; large messages will be
                     divided into several messages, each smaller than
                     this size
    MODE             Set the default file reading mode
    PURGE/LIST       Purge comment lines (such as unsubscribed
                     addresses) from the membership list
    QUIT (see END)   Same as END
    SEND             Retrieve the specified files
    SEND/LIST        Retrieve the membership list for a given mailing
                     list
    SEND/LIST/COMMENTRetrieve the membership list for a given mailing
    (see SEND/LIST)  list, including members' RFC 822 comment fields
    SEND/LIST/NOCOMMERetrieve the membership list for a given mailing
    (see SEND/LIST)  list, stripping members' RFC 822 comment fields
    STOP (see END)   Same as END
    SUBSCRIBE        Subscribe to a mailing list
    UNSUBSCRIBE      Unsubscribe from a mailing list