Nevis Linux Cluster - Shells
Some comments on the UNIX shells available on the Nevis Linux cluster.
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:
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
environment modules (the
module
command) 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 set some shell history variables and create the following file if it does not already exist: |
~/.cshrc |
~/.profile |
~/.zprofile |
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 |
~/.bashrc |
~/.zshrc |
If you use the Nevis user-specific initialization scripts, this is sourced to initialize the environment modules: |
/usr/nevis/adm/nevis-init.csh |
/usr/nevis/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 |