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mesg(1) General Commands Manual mesg(1) NAME mesg - Permits or refuses write messages SYNOPSIS mesg [-][y[es] | n[o]] STANDARDS Interfaces documented on this reference page conform to industry stan- dards as follows: mesg: XPG4, XPG4-UNIX Refer to the standards(5) reference page for more information about in- dustry standards and associated tags. OPTIONS This permits other users to send messages to your terminal. [DIGITAL] The leading - (dash) is optional. Only the initial letter is required, but the full word is accepted. This denies other users permission to send messages to your terminal. Dis- ables incoming write messages, except by appropriately autho- rized users. [DIGITAL] The leading - (dash) is optional. Only the initial letter is required, but the full word is accepted. If no option is specified, mesg reports the current state of message acceptance. OPERANDS [DIGITAL] There are no operands to mesg, but if the optional (-) hy- phen is omitted with the option, then the option becomes the operand as described in the XPG4, XPG4-UNIX standard. DESCRIPTION The mesg command controls whether other users on the system can send messages to you with the talk and write commands. Called without argu- ments, mesg displays the current terminal message permission setting. [DIGITAL] The shell start-up procedure disallows messages by default. You can override this default action by including the line mesg y in your $HOME/.profile (sh), (csh), or (csh) file. Note [DIGITAL] This default setting described for the shell start-up proce- dure message permissions assumes that the shell is one started as part of a login session. If the shell got started by some other means, the default depends on what that other program has done. [DIGITAL] Any user can send messages with write if the receiving user has enabled messages. A user with the sysadmin command authorization can send messages to any terminal. 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, respectively. (In other words, the affected device is not the same as the controlling terminal for the session.) [DIGITAL] Message permission has no effect on messages delivered through the electronic mail system. [DIGITAL] If you add mesg y to your $HOME/.profile, you will be able to receive messages from other users via the write command or the talk command. If you add mesg n to your $HOME/.profile, you will not be able to receive messages from other users via the write command or the talk command. The mesg command also accepts the current locale's equivalent of yes and no. These equivalents are determined by the setting of the LC_MES- SAGES environment variable. The usage message displays the current lo- cale's equivalent of yes and no. Security Restrictions [DIGITAL] In the trusted configuration of the system, all terminal de- vices have owner set to the login user and group set to the pseudogroup tty. The login command sets terminal modes to 0600 at login time, so you must explicitly use mesg y to enable access from unauthorized users. NOTES [DIGITAL] If your current locale defines settings other than yes or no, the mesg command does not accept yes or no as arguments. This causes an error if you use a yes or no argument to mesg in your file. EXIT STATUS The following exit values are returned: Message reception is allowed. Message reception is denied. An error occurred. EXAMPLES To allow only appropriately authorized users to send messages to your terminal, enter: mesg no To allow everyone the permission to send mes- sages to your terminal, enter: mesg yes To determine the state of mes- sage acceptance of your terminal, enter: mesg This will give one of the following responses, as appropriate: is yes is no ENVIRONMENT VARIABLES The following environment variables affect the execution of mesg: Pro- vides a default value for the internationalization variables that are unset or null. If LANG is unset or null, the corresponding value from the default locale is used. If any of the internationalization vari- ables contain an invalid setting, the utility behaves as if none of the variables had been defined. If set to a non-empty string value, over- rides the values of all the other internationalization variables. De- termines the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi- byte characters in arguments). Determines the locale for the format and contents of diagnostic messages written to standard error. Deter- mines the location of message catalogues for the processing of LC_MES- SAGES. FILES User profile User profile (csh) User profile (csh) Your current termi- nal SEE ALSO Commands: chmod(1), csh(1), Bourne shell sh(1b), POSIX shell sh(1p), stty(1), talk(1), wall(1), write(1) Functions: chmod(2) Standards: standards(5) mesg(1)