Date of last revision: 12/11/1998

A shell is what you use to interface with the Unix operating system with the keyboard. Unless you have changed your shell, you should be using the Bourne-Again Shell (older accounts may still be set up with Posix Shell).

When a shell is invoked as a 'login' shell (e.g. when you login or when you first open a terminal window in windows), it will execute certain 'initialization' files in your account (typically called 'dot' files). An 'interactive' or 'subshell' may be created from with several unix programs. These are not *login* shells because they were not created at the time you logged on or first opened the terminal window.

When your account was created, we give very basic initialization files: .cshrc, .login, and .profile. These files will work with any shell currently on the system. Some shells can use other initialization files as well as the supplied ones. See below and the man pages for details.

When a shell is 'terminated' (e.g. you press CTRL-D or type exit), something can be done on logout. This varies from shell to shell.

The shells (with their initialization files) are:


Bourne Shell


Posix Shell


Korn Shell


Description: Incorporates some of the best features of tcsh and ksh into a sh-compatible shell. Intended to be a conformant implementation of the POSIX Shell and Tools specification (IEEE Working Group 1003.2).

Bourne-Again Shell

Bash has its own helpme file.

Z Shell

Description: Incorporates some of the best features of csh and ksh into a sh-compatible shell.

Zsh has its own helpme file.


C Shell


Turbo C Shell

Description: An enhanced version of csh that incorporates command line editing, filename completion, and other advanced features. Intended to be fully compatible with csh, but a small number of packages/commands/etc may not work properly with tcsh.

Tcsh has its own helpme file.


CHANGING YOUR DEFAULT SHELL

On an HP Unix workstation, type:

ypchsh <login> [shell]

where <login> is your login name, and shell is one of:

/usr/bin/sh
/usr/bin/csh
/usr/bin/ksh
/usr/local/bin/tcsh
/usr/local/bin/bash
/usr/local/bin/zsh

Note: The chsh command does not work! Do not use it!

You can also just type the name of the shell to run the shell without setting it as your default. This is the best way to compare the various shells.

If you do not know which shell you would like to use, the Design Center recommends the Bourne-Again Shell.


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