-xv
form also inhibits the cmail introduction message.
$CMAIL_DIR
or failing that, $CHESSDIR
,
$HOME/Chess or ~/Chess. It will be created if it does not exist.
$CMAIL_ARCDIR
or, in its absence, the same
directory as cmail keeps its working files (above).
$CMAIL_MAILPROG
or failing that
/usr/ucb/Mail, /usr/ucb/mail or Mail. You will need
to set this variable if none of the above paths fit your system.