sh(1) [osf1 man page]
sh(1) General Commands Manual sh(1) NAME
sh - Shell, the standard command language interpreter DESCRIPTION
[Tru64 UNIX] Tru64 UNIX provides two command interpreters with the name sh. The XCU5.0 and POSIX.2 compliant command interpreter sh is available in the file /usr/bin/posix/sh and is described in the sh(1p) reference page. The Bourne shell, historically known as sh, is available in the file /usr/bin/sh and is described in the sh(1b) reference page. [Tru64 UNIX] Your initial, or login, shell is determined by your entry in the file /etc/passwd. This file can be changed only by your sys- tem administrator. You must use whatever procedures are in place at your location to have this entry changed. [Tru64 UNIX] If available on your system, you may use the passwd -s or the chsh commands to change your login shell. Note This option is not available if your site manages passwords through the Network Information Service (NIS) facility. Check with your system administrator. [Tru64 UNIX] Subsequent shells spawned from the initial shell depend on the value in the environment variable BIN_SH. If this variable is set to xpg4, the POSIX shell is started. If this variable is set to svr4, an SVR4 compliant version of the shell is started. If this vari- able is unset, the Bourne shell is started. If this variable is set to any other value, an error is reported and the results are unpre- dictable. See the EXAMPLES section for information on setting this variable. NOTES
[Tru64 UNIX] With Tru64 UNIX Version 4.0 the Korn shell, /usr/bin/ksh is the same as the POSIX shell /usr/bin/posix/sh. RESTRICTIONS
[Tru64 UNIX] The file /etc/shells must include entries for both the POSIX shell /usr/bin/posix/sh and the Bourne shell, /usr/bin/sh. If this file is incorrect, see your system administrator. EXAMPLES
Using the Bourne, Korn, or POSIX shell, to set the variable BIN_SH to use the POSIX/ XCU5.0compliant shell, enter: BIN_SH=xpg4 export BIN_SH Using the Bourne, Korn, or POSIX shell, to set the variable BIN_SH to use the SVR4 compliant shell, enter: BIN_SH=svr4 export BIN_SH Using the Bourne, Korn, or POSIX shell, to unset the variable BIN_SH, enter: unset BIN_SH Using the C/ shell, to set the variable BIN_SH to use the POSIX/XCU5.0 compliant shell, enter: setenv BIN_SH xpg4 Using the C/ shell, to set the variable BIN_SH to use the SVR4 compliant shell, enter: setenv BIN_SH svr4 Using the C/ shell, to unset the variable BIN_SH, enter: unsetenv BIN_SH FILES
User profile. Contains user information, including the login shell name. Contains the names of available and permitted shells. SEE ALSO
Commands: csh(1), ksh(1), Bourne shell sh(1b), POSIX shell sh(1p), passwd(1) Files: passwd(4), shells(4) Standards: standards(5) sh(1)
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mesg(1) General Commands Manual mesg(1) NAME
mesg - Permits or refuses write messages SYNOPSIS
mesg [y | n ] [Tru64 UNIX] The following format is supported for backward compatibility: mesg [[-]y[es] | [-]n[o] ] STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: mesg: XCU5.0 Refer to the standards(5) reference page for more information about industry standards and associated tags. OPERANDS
Grants permission to other users to send messages to the terminal device. [Tru64 UNIX] You can optionally include a - (hyphen) before y, include es after y, or both. Denies permission to other users to send messages to the terminal device. [Tru64 UNIX] You can optionally include a - (hyphen) before n, include o after n, or both. DESCRIPTION
The mesg command controls whether other users on the system can send messages to you with the talk and write commands. Called without arguments, mesg displays the current terminal message permission setting. [Tru64 UNIX] 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 [Tru64 UNIX] This default setting described for the shell start-up procedure 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. [Tru64 UNIX] Any user can send messages with write if the receiving user has enabled messages. A user with the sysadmin command autho- rization 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.) [Tru64 UNIX] Message permission has no effect on messages delivered through the electronic mail system. [Tru64 UNIX] 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_MESSAGES environment variable. The usage message displays the current locale's equivalent of yes and no. Security Restrictions [Tru64 UNIX] In the trusted configuration of the system, all terminal devices have owner set to the login user and group set to the pseu- dogroup tty. The login command sets terminal modes to 0600 at login time, so you must explicitly use mesg y to enable access from unautho- rized users. NOTES
[Tru64 UNIX] 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 messages to your terminal, enter: mesg yes To determine the state of message 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: Provides 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, overrides the values of all the other internationalization variables. Determines the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multibyte characters in arguments). Determines the locale for the for- mat and contents of diagnostic messages written to standard error. Determines the location of message catalogues for the processing of LC_MESSAGES. FILES
User profile User profile (csh) User profile (csh) Your current terminal 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)