php man page for mesg

MESG(1)                                                            User Commands                                                           MESG(1)

NAME
       mesg - display (or do not display) messages from other users

SYNOPSIS
       mesg [option] [n|y]

DESCRIPTION
       The mesg utility is invoked by a user to control write access others have to the terminal device associated with standard error output.  If
       write access is allowed, then programs such as talk(1) and write(1) may display messages on the terminal.

       Traditionally, write access is allowed by default.  However, as users become more conscious of various security risks, there is a trend  to
       remove write access by default, at least for the primary login shell.  To make sure your ttys are set the way you want them to be set, mesg
       should be executed in your login scripts.

ARGUMENTS
       n      Disallow messages.

       y      Allow messages to be displayed.

       If no arguments are given, mesg shows the current message status on standard error output.

OPTIONS
       -v, --verbose
              Explain what is being done.

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text and exit.

EXIT STATUS
       The mesg utility exits with one of the following values:

            0     Messages are allowed.

            1     Messages are not allowed.

           >1     An error has occurred.

FILES
       /dev/[pt]ty[pq]?

SEE ALSO
       login(1), talk(1), write(1), wall(1), xterm(1)

HISTORY
       A mesg command appeared in Version 6 AT&T UNIX.

AVAILABILITY
       The mesg command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.

util-linux                                                           July 2014                                                             MESG(1)