comsat - The biff server
The comsat server receives reports of incoming mail and notifies users who
request this service. comsat is invoked by the inetd(8) daemon when it
receives messages on a datagram port associated with the biff(1) service
specification in /etc/services(4). The datagram contains a 1-line message
of the form:
If the user specified is logged in and the associated terminal has the
owner execute bit turned on (with biff y), offset is used as a seek offset
into the file named in mailbox. The first 7 lines or 560 characters of the
message are printed on the user's system. The message excludes mail header
lines other than the From or Subject lines.
The comsat command always tries to convert incoming mail messages from the
mail interchange codeset to the user's application codeset. It determines
the mail interchange code first by checking the mail message itself to see
if it contains the required information. Otherwise, the system-wide default
mail interchange code in the file /usr/lib/mail-codesets will be used. If
no such system file exists, no codeset conversion will be performed.
The determination of the user's application code in each terminal session
is by one of the following methods.
+ The application codeset defined in the user's Asian tty driver.
+ The codeset name stored in the ~/.codesetdevname file, where devname
is the name of the terminal device for the current terminal session.
You can obtain the value of devname by issuing the tty command. For
example, if the tty command returns /dev/ttys8, use ttys8 as the value
+ The lang valued option defined in $HOME/.mailrc or
Specifies the command path.
Includes information about logged-in users and their associated ttys.
File containing mailx subcommands to customize mailx for a specific
File containing mailx subcommands to change mailx for all users on the
Commands: biff(1), inetd(8), mailx(1), mh(1)
Files: services(4), inetd.conf(4), tty(7)