WALL(1) (Essential Utilities) WALL(1)
NAME
wall - write to all users
SYNOPSIS
/etc/wall
DESCRIPTION
wall reads its standard input until an end-of-file. It then
sends this message to all currently logged-in users preceded
by:
Broadcast Message from ...
It is used to warn all users, typically prior to shutting
down the system.
The sender must be super-user to override any protections
the users may have invoked (see mesg(1)).
FILES
/dev/tty*
SEE ALSO
mesg(1), write(1).
DIAGNOSTICS
``Cannot send to ...'' when the open on a user's tty file
fails.
Page 1 May 1989