COMSAT(8)

NAME
comsat - biff server

SYNOPSIS
comsat

DESCRIPTION
The comsat utility is the server process which receives reports of incoming mail and notifies users if they have requested this service. The comsat utility receives messages on a datagram port associated with the “biff” service specification (see services(5) and inetd(8)). The one line messages are of the form:

    user@mailbox-offset[:mailbox-name]

If the user specified is logged in to the system and the associated terminal has the owner execute bit turned on (by a “biff y”), the offset is used as a seek offset into the appropriate mailbox file and the first 7 lines or 560 characters of the message are printed on the user's terminal. Lines which appear to be part of the message header other than the “From”, “To”, “Date”, or “Subject” lines are not included in the displayed message.

If the user specified is logged in to the system and the associated terminal has the group execute bit turned on (by a “biff b”), two bell characters (ASCII \007) are printed on the user's terminal.

If mailbox-name omitted, standard mailbox assumed.

FILES
/var/run/utmpx
    to find out who is logged on and on what terminals
/var/mail/user
    standard mailbox

SEE ALSO
biff(1), inetd(8)

HISTORY
The comsat utility appeared in 4.2BSD.

BUGS
The message header filtering is prone to error. The density of the information presented is near the theoretical minimum.

Users should be notified of mail which arrives on other machines than the one to which they are currently logged in.

The notification should appear in a separate window so it does not mess up the screen.