Sending messages to user terminals
Linux supports three applications to display messages on another user's screen. The write
command sends a message to a user, the talk
command lets two users have a conversation, and the wall
command sends a message to all users.
Before doing something potentially disruptive (say, rebooting the server), the system administrator should send a message to the terminal of every user on the system or network.
Getting ready
The write
and wall
commands are part of most Linux distributions. If a user is logged in multiple times, you may need to specify the terminal you wish to send a message to.
You can determine a user's terminals with the who
command:
$> who user1 pts/0 2017-01-16 13:56 (:0.0) user1 pts/1 2017-01-17 08:35 (:0.0)
The second column (pts/#
) is the user's terminal identifier.
The write
and wall
programs work on a single system. The talk
program can connect users across a network.
The talk program is not commonly installed. Both the...