wall(1M)          MISC. REFERENCE MANUAL PAGES           wall(1M)



NAME
     wall - write to all users

SYNOPSIS
     /usr/sbin/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)].

     wall runs setgid() [see setuid(2)] to the group ID  tty,  in
     order to have write permissions on other user's terminals.

     wall will detect  non-printable  characters  before  sending
     them to the user's terminal.  Control characters will appear
     as a `^' followed by the appropriate ASCII character;  char-
     acters with the high-order bit set will appear in meta nota-
     tion. For example, `\003' is displayed as `^C' and `\372' as
     `M-z'.

FILES
     /dev/tty*

SEE ALSO
     mesg(1), write(1).

NOTES
     ``Cannot send to ...'' when the open on a  user's  tty  file
     fails.

















                Last change: Essential Utilities                1