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UNIX for Dummies Questions & Answers
Variables and math in Old skool Bourne Shell
Post 302677231 by neutronscott on Wednesday 25th of July 2012 06:55:38 PM
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LEARN ABOUT OSF1
sh
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)