32v 1m wall
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WALL(1M) UNIX Programmer's Manual WALL(1M)
NAME
wall - write to all users
SYNOPSIS
/etc/wall
DESCRIPTION
_W_a_l_l reads its standard input until an end-of-file. It then sends this message, preceded by `Broadcast Message ...', to all logged in users.
The sender should be super-user to override any protections the users may have invoked.
FILES
/dev/tty? /etc/utmp
SEE ALSO
mesg(1), write(1)
DIAGNOSTICS
`Cannot send to ...' when the open on a user's tty file fails.