Communicating with other users on the Linux command line

The wall command (as in “write all”) allows you to send a message to all users who are currently logged into the system. This implies that the system is likely a server and that users are working on the command line. While the wall command is generally used by sysadmins to send out notices to users to let send out information (e.g., that the server is going down for maintenance), it can be used by any user.