Set write permissions for the current terminal
mesg command is used to set the write permission of the current terminal, that is, whether to allow other users to send messages to this terminal. When mesg is set to y, other users can use the write command to display information directly on your screen.
mesg(parameter)
y/n: y means to run writing information to the current terminal, n means to prohibit writing information to the current terminal.
[root@localhost ~]# mesg y #Allow system users to display information directly on your screen.
[root@localhost ~]# mesg n #Do not allow system users to display information directly on your screen.