wall(1M)

NAME

     wall - write to all users

SYNOPSIS

     /usr/sbin/wall [-a] [-g grpname] [filename]

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 ...

     If filename is given, then the message is read in from  that
     file.  Normally,  pseudo-terminals that do not correspond to
     rlogin sessions are ignored. Thus, when using a window  sys-
     tem,  the  message  appears only on the console window. How-
     ever,  -a  will  send  the  message  even  to  such  pseudo-
     terminals.

     It is used to warn all users, typically  prior  to  shutting
     down the system.

     The sender must be superuser to override any protections the
     users may have invoked See mesg(1).

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

     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;
     characters with the high-order bit set will appear in "meta"
     notation.  For example, `\003'  is  displayed  as  `^C'  and
     `\372' as  `M-z'.

OPTIONS

     The following options are supported:

     -a    Broadcast message to the console and pseudo-terminals.

     -g grpname
           Broadcast to the users in a specified group only,  per
           the group database (see group(4)).

ENVIRONMENT VARIABLES

     If  the   LC_*  variables  (LC_CTYPE,  LC_TIME,  LC_COLLATE,
     LC_NUMERIC, and LC_MONETARY) are not set in the environment,
     the operational behavior  of  wall  for  each  corresponding
     locale  category  is  determined  by   the value of the LANG
     environment variable. See environ(5). If LC_ALL is set,  its
     contents  are  used to override both the  LANG and the other
     LC_* variables. If none of the above variables  are  set  in
     the  environment, the "C" (U.S. style) locale determines how
     wall behaves.

FILES

     /dev/tty*

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    | Availability                | SUNWcsu                     |
    |_____________________________|_____________________________|

SEE ALSO

     mesg(1), write(1), setuid(2), attributes(5), environ(5)

NOTES

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