• Top Linux Shells

Nevis Linux Cluster - Shells

In UNIX, a "shell" is the command-line interface to the operating system and programs on the machine. For a more detailed description of the types of shells available, see:

• A Shell Comparison
• UNIX shell differences

You can change your login shell using the ypchsh command.

On the Redhat and Fedora Linux distributions in the cluster, bash and tcsh are always installed. sh and csh are not available separately; they're linked to bash and tcsh respectively. I try to also install zsh and ksh on each system as well, but they can be omitted. If you require either of these shells and they're not available on your machine, let me know and I'll install them.

The Nevis-based commands setup and unsetup should work equally well under all the above shells, provided you have initialized your environment correctly.

As you try to understand how your shell environment is set up, it may be helpful to know the initialization procedure that's performed everytime you start a shell, given the Redhat and Nevis extensions:

Process	C-style shells (csh and tcsh)	Bourne-style shells (sh, bash, and ksh)	zsh
The first script that's sourced is:	/etc/csh.cshrc	/etc/profile	/etc/zshenv
If this is a login shell, this file is also sourced:	/etc/csh.login		/etc/zprofile
The above scripts execute additional scripts in:	/etc/profile.d/*.csh		/etc/profile.d/*.sh
...including the Nevis-specific scripts:	/etc/profile.d/nevis.csh		/etc/profile.d/nevis.sh
All that the above Nevis-specific scripts do is define ${NevisAppBase} and create the following file if it does not already exist:	~/.cshrc	~/.profile	~/.zshrc
The shell then sources the user-specific initialization scripts (same as previous line), which you can edit and override if you wish (though I don't recomment it):	~/.cshrc	~/.profile	~/.zshrc
If you use the Nevis user-specific initialization scripts, this is sourced to initialize the setup and unsetup commands:	${NevisAppBase}/adm/nevis-init.csh		${NevisAppBase}/adm/nevis-init.sh
The standard Nevis user-specific script then sources these files, which are intended for you to set up your custom environment:	~/.mycshrc		~/.myprofile