
NAME
wall  -  write to all users

SYNOPSIS
/etc/wall [file]

DESCRIPTION
If a filename is given, wall reads from it; if not, it reads from
its standard input  until  an  end-of-file.   It  then sends this
message to all currently logged in users preceded by the header:

Broadcast message from -----

(where ----- is the user running the wall)
It is used to warn all users, typically prior  to  shutting  down
the system.


The sender should be super-user to override any  protections  the
users may have invoked.

Purdue Mods:
Users in /usr/include/staff.h may use wall without
being superuser as wall temporarily makes them superuser when
it runs.

FILES
/dev/tty?

SEE ALSO
mesg (I), write (I)

DIAGNOSTICS
a user's tty file fails.

BUGS
Wall forks for each terminal logged in. If the number of forks
is 20, additional forks will fail and those terminals which
fail will not get the message.


