MESG(1)                      General Commands Manual                     MESG(1)

     mesg – display (do not display) messages from other users

     mesg [n | y]

     The mesg utility is invoked by a user to control write access others have
     to a terminal device.  Write access is allowed by default, and programs
     such as talk(1) and write(1) may display messages on the terminal.

     The first terminal device in the sequence of devices associated with
     standard input, standard output and standard error is affected.

     Options available:

     n     Disallows messages.

     y     Permits messages to be displayed.

     If no arguments are given, mesg displays the present message status to the
     standard output.

     Disallow messages from other users to the current terminal:

           mesg n

     Allow messages from other users to ttyp1 (assuming you are also logged in
     on that terminal):

           mesg y </dev/ttyp1

     The mesg utility exits with one of the following values:

            0    Messages are allowed.
            1    Messages are not allowed.
           >1    An error has occurred.

     Previous versions of the mesg utility wrote the message status to the
     standard error output and affected the terminal attached to standard error
     without first trying the standard input or output devices.

     biff(1), talk(1), wall(1), write(1)

     The mesg utility conforms to IEEE Std 1003.1-2001 (“POSIX.1”).

     A mesg command appeared in Version 1 AT&T UNIX.

macOS 12.1                         May 5, 2002                        macOS 12.1