1. Check the status
mesgwho -T
2. Open the message
mesg y
3. Write a message
write [user]
發送測試訊息
user@user-pc:~/$ who -T
user_a + tty1 2020-04-13 19:00
user - tty7 2020-04-13 19:00 (:0)
user@user-pc:~/$ mesg
is n
user@user-pc:~/$ mesg y
is y
user@user-pc:~/$ write user_a
Hello, World.
# CTRL+C leave
To all online user
user@user-pc:~/$ wall "Hello, World."
user@user-pc:~/$ wall
Hello, World.
# CTRL+D send message.