WALL(1) — User’s Manual — Commands
NAME
wall − write to all users
SYNOPSIS
wall [ file ]
DESCRIPTION
Wall 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
Sun System Release 0.3 — 16 March 1983