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...