mesg [option] [n|y]
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.
If no arguments are given, mesg shows the current message status on standard error output.
The mesg utility exits with one of the following values:
talk(1), write(1), wall(1), login(1), xterm(1)
A mesg command appeared in Version 6 AT&T UNIX.
The mesg command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.