There is a pretty cool command in all Linux versions (including Mint / Ubuntu) by which you can broadcast messages to all users who have their terminals open. Even more useful is the fact that you can actually display all the contents of a file to all the logged in users.
This command is called the wall (maybe that’s how Facebook got it ). General format of this is : wall <filename>.
Here is something fun to do :
1. Login as a root
2. Suppose the file here is the standard MOTD (message of the day) that needs to be broadcast to all the users. To do this :
3. Notice how the message was received to the other open Terminal (with standard non-root user logged in).
4. Suppose, to display the contents of a file named greetings.txt, simply type :
5. Here is what is seen on user screens :
Actually, this is the really old school way by which you can notify your users about various things. Back in olden days when everything was non graphical, system admins either used to put latest announcements of maintenance schedules in MOTD or simply put that in a file and used wall to let the file contents be displayed to all logged in users.
Also, there is a variation of this command called rwall that will do the same thing for users who are logged in remotely.
Happy wall writing!