rwall - write to all users over a network
/usr/sbin/rwall hostname ...
/usr/sbin/rwall -n netgroup ...
/usr/sbin/rwall -h host -n netgroup
rwall reads a message from standard input until EOF, then sends the
message, preceded by the line Broadcast Message ..., to all users
logged in on the specified host machines. With the -n option, rwall
sends the message to the specified network hosts defined in
/etc/netgroup (see netgroup(4)).
A machine can only receive such a message if it is running rwalld,
which is normally started from /etc/inetd.conf by the inetd daemon
The timeout is kept fairly short so that the message can be sent to a
large group of machines (some of which may be down) in a reasonable
amount of time. Thus, the message may not get through to a heavily
rwall was developed by Sun Microsystems, Inc.
rwalld(1M), shutdown(1M), wall(1M), netgroup(4).
Hewlett-Packard Company - 1 - HP-UX Release 11i: November 2000