Linux and Unix mesg command
Lets you control if people can use the write command, to send text to you over the screen.
|n||Prevents the messages from others popping up on your screen.|
|y||Allows messages to appear on your screen.|
Typing this command by itself will display whether or not the mesg service is enabled. For example, it may display: "is y", indicating that it is enabled. Typing n or why after the command would enable or disable this command.
When this command is disabled non-root users will be unable to to send messages to you using message commands such as talk or write.