MESG(1)                                                                MESG(1)


NAME
     mesg - permit or deny messages

SYNOPSIS
     mesg [ y | n ]

DESCRIPTION
     mesg with argument n forbids messages via write(1) , talk or other
     utilities by revoking non-user write permission on the user's terminal.
     The terminal affected is determined by searching for the first terminal
     in the sequence of devices associated with standard input, standard
     output and standard error, respectively.  mesg with argument y reinstates
     permission.  All by itself, 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.

OPTIONS
     None.

OPERANDS
     The following operands are supported in the POSIX locale:

     y    grant permission to other users to send messages to the terminal
          device

     n    deny permission to other users to send messages to the terminal
          device

STDIN
     Not used.

ENVIRONMENT VARIABLES
     The following environment variables affect the execution of mesg:

     LANG provide a default value for the internationalization variables that
          are unset or null.  If LANG is unset or null the corresponding value
          from the implementation-specific default locale will be used. If any
          of the internationalization variables contains an invalid setting,
          the utility will behave as if none of the variables had been
          defined.

     LC_ALL
          if set to a non-empty string value, override the values of all the
          other internationalization variables.

     LC_CTYPE
          determine the locale for the interpretation of sequences of bytes of
          text data as characters (for example, single - as opposed to multi-
          byte - characters in arguments).


     LC_MESSAGES
          determine the locale that should be used to affect the format and
          contents of diagnostic messages written to standard error.

     NLSPATH
          determine the location of message catalogs for the processing of
          LC_MESSAGES.

STDOUT
     If no operand is specified, mesg displays the current terminal state in
     an unspecified format.

STDERR
     Used donly for diagnostic messages.

EXIT STATUS
     The following exit values are returned:
     0   receiving messages is allowed
     1   receiving messages is not allowed
     >1  an error occurred

FILES
     /dev/tty*
     /usr/lib/locale/locale/LC_MESSAGES/uxcore language-specific message file
     [See LANG on environ(5).]

SEE ALSO
     write(1).

DIAGNOSTICS
     Exit status is 0 if messages are receivable, 1 if not, 2 on error.


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