Environment Modules

Welcome to the Environment Modules documentation portal. The Environment Modules package provides for the dynamic modification of a user’s environment via modulefiles.

The Modules package is a tool that simplify shell initialization and lets users easily modify their environment during the session with modulefiles.

Each modulefile contains the information needed to configure the shell for an application. Once the Modules package is initialized, the environment can be modified on a per-module basis using the module command which interprets modulefiles. Typically modulefiles instruct the module command to alter or set shell environment variables such as PATH, MANPATH, etc. modulefiles may be shared by many users on a system and users may have their own collection to supplement or replace the shared modulefiles.

Modules can be loaded and unloaded dynamically and atomically, in an clean fashion. All popular shells are supported, including bash, ksh, zsh, sh, csh, tcsh, fish, as well as some scripting languages such as tcl, perl, python, ruby, cmake and r.

Modules are useful in managing different versions of applications. Modules can also be bundled into metamodules that will load an entire suite of different applications.

Quick examples

Here is an example of loading a module on a Linux machine under bash.

$ module load gcc/6.1.1
$ which gcc
$ /usr/local/gcc/6.1.1/linux-x86_64/bin/gcc

Now we’ll switch to a different version of the module

$ module switch gcc gcc/6.3.1
$ which gcc

And now we’ll unload the module altogether

$ module unload gcc
$ which gcc
gcc not found

Now we’ll log into a different machine, using a different shell (tcsh).

% module load gcc/6.3.1
% which gcc

Note that the command line is exactly the same, but the path has automatically configured to the correct architecture.


Modules is distributed under the GNU General Public License version 2 (GPL v2).