Sending messages to user terminals

A system administrator may need to send messages to the terminal of every user or a specified user on all the machines over a network. This recipe is a guide on how to perform this task.

Getting ready

wall is a command that is used to write messages on the terminals of all logged in users. It can be used to convey messages to all logged in users on a server or multiple access machines. Sending messages to all users may not be useful at all times. Terminals are treated as devices in a Linux system and hence, these opened terminals will have a corresponding device node file at /dev/pts/. Writing data to a specific device will display messages on the corresponding terminal.

How to do it...

In order to broadcast a message to all users and all logged in terminals, use:

$ cat message | wall

Or:

$ wall< message
Broadcast Message from slynux@slynux-laptop
        (/dev/pts/1) at 12:54 ...

This is a message

The message outline will show who sent the message (which...