mesg — Permit or Deny Messages
/usr/bin/mesg [-n | -y | n | y]
The mesg command controls whether other users can send messages to a terminal device by using write(1), talk(1), or other commands. The terminal device affected is determined by searching for the first terminal in the sequence of devices associated with standard input, standard output, and standard error. With no arguments, mesg reports the current state without changing it. Processes with appropriate privileges may be able to send messages to the terminal independently of the current state.
|-n | n||Deny permission to other users to send message to the terminal. See write(1).|
|-y | y||Grant permission to other users to send messages to the terminal. ...|