Sidebar: Using wall

Whereas write allows you to send a message to one user, wall sends a message to everyone currently logged on the system -- thus it is "write all". Since the user sending the message is also a user on the system, he/she receives the message the same as everyone else. The message, rather than being sent as it is entered, is buffered and not sent until Control-D is pressed.

Typically, the utility is used by a system administrator who needs to send a message to everyone.