DELIVER screens and automatically processes your incoming mail
    based on guidelines that you provide. Different actions can be
    taken based on a message's envelope or header addresses, subject,
    or content. These actions include delivering the message, filing
    the message away, forwarding the message, or even invoking a
    DCL command procedure to perform complex processing. Any actions
    taken occur immediately upon receipt of each message; you do not
    need to be logged in at the time a message is received in order
    for actions to be taken on your behalf.

    DELIVER is modelled after the MAILDELIVERY facility of the MMDF
    mail system. DELIVER is, however, completely distinct from MMDF
    and the formats of .MAILDELIVERY files for MMDF and MAIL.DELIVERY
    files for DELIVER are dissimilar.