WALL(1)                              SysV                              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.