NAME

wall − write to all users

SYNOPSIS

/etc/wall [-g groupname] [file]

DESCRIPTION

When wall is invoked without arguments, the standard input is read until an end-of-file.  It then sends this message to all currently logged-in users preceded by:

Broadcast Message from ...

If the −g groupname option is specified, wall sends the message to all currently logged-in groupname members (as specified in /etc/group) preceded by:

Broadcast Message from ... to group groupname

If the file option is specified, wall uses file as its standard input. 

Wall 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 has timing delays, and will take at least 30 seconds to complete. 

DIAGNOSTICS

“Cannot send to ...” when the open on a user’s tty file fails. 

DEPENDENCIES

Series 300 Diskless
In a cluster, wall will only broadcast the message to users on the system from which wall was executed.  An additional option, −c can be specified.  When −c is specified, wall sends the message to all currently logged-in users at every cluster node preceded by:

Broadcast Message from ... at cnode ...

AUTHOR

Wall was developed by AT&T and HP. 

FILES

/dev/tty∗

SEE ALSO

mesg(1), write(1). 

INTERNATIONAL SUPPORT

8- and 16-bit data, 8-bit filenames. 

Hewlett-Packard Company  —  May 11, 2021