mesg
with argument
-n
forbids messages via
write(1)
by revoking non-user
write permission on the user's terminal.
mesg
with argument
-y
reinstates permission.
All by itself,
mesg
reports the current state without changing it.
Files
/dev/tty
/usr/lib/locale/locale/LC_MESSAGES/uxcore
language-specific message file (see LANG on
environ(5))
Diagnostics
Exit status is 0 if messages are receivable,
1 if not, 2 on error.