Wall is to send messages to all users, the content of which is contained in”.
2、write userName tty
First, we use the WHO command to view the online users and their tty, and then send him a message with the write command. After entering the command, we enter the message mode. At this time, we can enter the message content and send it back to the train. Exit by pressing Ctrl + D.
If you don’t want to receive messages from other users write, close it with mesg-n and turn it on again as mesg-y