Sends a message to one or more users. The MAIL command works like
    the SEND command.

    Mail first prompts you for the name of the user or users that you
    want to receive the message.

    MAIL> MAIL
    To:

    You reply with the user names or with the file names of
    distribution lists in the following format:

    [[nodename::]username(s),...] [,] [@listname[,...]]

    Next, Mail prompts you for the subject of the mail message. To
    avoid the Subj: prompt, specify the /SUBJECT= qualifier with the
    MAIL command, and enclose the subject string in quotation marks.

    You can include a file specification with the MAIL command. If
    you specify a file name with the MAIL command, the text in that
    file is sent to the specified users. If you do not specify a file
    name, Mail prompts you for the text of your message.

    Enter the message that you want to send; then press Ctrl/Z. Note
    that once you type a line and press Return, there is no way to
    edit it. If you decide not to send the message you are typing
    but want to stay within the Mail utility, press Ctrl/C to abort
    the message. You then receive the MAIL> prompt. You can also
    enter CTRL/Y to cancel sending a mail message, however note that
    CTRL/Y will also quit your Mail process and return you to the DCL
    prompt.

    Format

      MAIL  [file-spec]