CAEN Knowledge Base
CAEN Knowledge Base

How are Environment Modules used in the CLSE for Linux?

  • Environment modules enable you to modify your Linux environment dynamically.
  • Modules can be loaded and unloaded using command-line programs.
  • In the CAEN Lab Software Environment (CLSE), modules are used to specify which version of a software application you wish to run.
  • Use the module avail command to display all available modules.
  • Use the module load module_name command to load a module.



The Linux Environment Modules package is available on all computers running the CAEN Lab Software Environment (CLSE) for Linux. This package enables you to change settings in your shell dynamically using software "modulefiles" pre-configured by CAEN for many applications. When you load a modulefile, your shell will be configured with all variables needed by the application (e.g. PATH, CLASSPATH, MANPATH, or LD_LIBRARY_PATH).

To determine which modulefiles and software versions are available, use the module avail command. If additional arguments are not specified, the command will display a listing of all modulefiles available to you. The list of all modules may be very long; to refine your search, you may add an additional argument to specify the modulefiles available for a specific application, e.g. module avail abaqus. The below image illustrates this:

To load a module, use the module load modulefile command. Your shell will be modified as specified in the modulefile. For example, in the below illustration, the gcc/4.3.2 modulefile is loaded. Prior to loading the modulefile, typing the gcc command would have run the version in /usr/bin. After loading the module, the user's PATH environment variable is modified such that the version of gcc in /usr/um/gcc-4.3.2 is run instead:

To restore your environment to its previous state, use the module unload modulefile command, or simply log out:

Read More About Environment Modules

For more information about the environment modules, commands, and usage, visit the SourceForge Environment Modules package project page or type man module or module --help at a command line.