"
wall" is one of the most important command for system administrators.
-
wall sends a message to everybody logged in with their
mesg permission set to "
yes". The message can be given as an argument to wall, or it can be sent to wall’s standard input.
root@server.com [~]# wall "we will be going down for maintenance for one hour sharply at 23:30 pm"
Broadcast message from root@server.com (pts/0) (Sun Jan 12 21:37:00 2014):
we will be going down for maintenance for one hour sharply at 23:30 pm
