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The Modules Package

Modules Approach to Managing The Environment

Modules is a system for providing software packages to the users. When the user wishes to use a software package, Modules will take care of the details of modifying their environment to include the new package. The distinct advantage of the modules approach is that the user is not required to explicitly specify paths for different executable versions and try to keep their related man paths and environment variables coordinated. Rather, users will simply "load" and "unload" specific modules to control their environment.

Getting Started with Modules

If you're using the standard startup files on the PDSF then you're already setup for using Modules. If module command is not available, clean up your login environment, please.

Using Modules

Modules has two major commands:

load loads a software package

unload unloads a software package

For example, the user who wants to start using TeX types

module load tex

This action modifies the users PATH and MANPATH while also setting up any necessary environment variables for TeX to work. Replacing the "load" option with "unload" will remove these modifications. To load a particular version of the package (when available) one can include this specification in the load command. That is,

module load tex/3.pl141.old

will load the version 3.pl141.old of the TeX software.

To examine what a module will do, the command display can be used,

module display tex

to produce the following information (Press button for example.).

In this illustration, The Module load command will do the following,

(1) prepends the path to the TeX routines to the PATH,

(2) prepended the man path for the TeX routines to the MANPATH,

(3) set the environment variables TEXFORMATS, TEXFONTS, and TEXPOOL

(4) set the aliases latex209 and latex2e

 

Notice that the environment variables, the PATH, and the MANPATH have all been changed. By using modules, users only need to load and unload modules to keep their entire environment coordinated.

Other useful features are included with the list and avail commands.

module list (lists currently loaded modules)

module avail (lists the modules available to the user)

 

Additional information about Modules can be found on the Modules Project page

Customizing Modules

For loading a particular set of modules automatically at login, place the module load commands in the ~/.cshrc file. See Shells and Startup Files for more information.