WALL(8) Maintenance Commands and Procedures WALL(8)

NAME

wall - write to all users

SYNOPSIS

/usr/sbin/wall [-a] [-g grpname] [-z zonename] [-Z] [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 system, the message appears
only on the console window. However, -a will send the message even to
such pseudo-terminals. Normally, wall sends messages to the current
zone only, from the global zone -Z will send messages to all
nonglobal zones, and -z will send messages to a specified nonglobal
zone


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(5)).


-z zonename
Broadcast to the users in a specified zone only


-Z
Broadcast message to the console and pseudo-terminals
of all zones.

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(7). 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*

SEE ALSO

mesg(1), write(1), setuid(2), attributes(7), environ(7)

NOTES

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

July 13, 1994 WALL(8)