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, cmd, pwsh, 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 meta-modules that will load an entire suite of different applications.

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

$ module load gcc/12.4.0
$ which gcc
$ /usr/local/gcc/12.4.0/linux-x86_64/bin/gcc

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

$ module switch gcc/14
$ which gcc
/usr/local/gcc/14.2.0/linux-x86_64/bin/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/14.2
% which gcc
/usr/local/gcc/14.2.0/linux-aarch64/bin/gcc

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

The simplest way to build and install Modules on a Unix system is:

$ ./configure
$ make
$ make install

To learn the details on how to install modules see INSTALL.txt for Unix system or INSTALL-win.txt for Windows.

• Tcl >= 8.5

See MIGRATING to get an overlook of the new functionalities introduced by each released versions. NEWS provides the full list of changes added in each version. The Changes document gives an in-depth view of the modified behaviors and new features between major versions. You may also look at the ChangeLog for the technical development details.

The doc directory contains both the paper and man pages describing the user's and the module writer's usage. To generate the documentation files, like the man pages (you need Sphinx >= 1.0 to build the documentation), just type:

$ ./configure
$ make -C doc all

The following man pages are provided:

module(1), ml(1), modulecmd(1), envml(1), modulefile(5)

Regression testing scripts are available in the testsuite directory (you need DejaGnu to run the test suite):

$ ./configure
$ make test

Once modules is installed after running make install, you have the ability to test this installation with:

$ make testinstall

• Web site: https://envmodules.io
• Online documentation: https://modules.readthedocs.io
• GitHub source repository: https://github.com/envmodules/modules
• GitHub Issue tracking system: https://github.com/envmodules/modules/issues

Modules is an open source project. Questions, discussion, and contributions are welcome. You can get in contact with the Modules community via:

• the modules-interest mailing list ([email protected])
• the Modules chat room (#modules:matrix.org)
• the Technical Steering Committee meeting

The project is also present on several social media platforms:

• X/Twitter: @EnvModules
• Mastodon: @[email protected]
• Bluesky: @EnvModules.bsky.social

Modules project welcomes contributions of all kinds! Before submitting an issue or pull request, please take a moment to review our Contributing guide. It includes important information about issue reporting, coding standards, etc.

Please note that Modules project has a Code of conduct. It ensures a respectful and inclusive environment for all contributors. By participating in the Modules community, you agree to abide by its rules.

Modules is part of the High Performance Software Foundation within the Linux Foundation.

This project adheres to a Technical charter, which defines its governance model, decision-making process, and long-term vision.

Modules is distributed under the GNU General Public License, either version 2 or (at your option) any later version (GPL-2.0-or-later). Read the file COPYING for details.

Modules current maintainers are:

• Xavier Delaruelle, [email protected]
• Adrien Cotte, [email protected]

Many thanks go to the contributors of the Modules project.

We would like to express our gratitude to CEA for the resources and funding provided to the project over the recent years.

The following people have notably contributed to Modules and Modules would not be what it is without their contributions:

• R.K. Owen
• Kent Mein
• Mark Lakata
• Harlan Stenn
• Leo Butler
• Robert Minsk
• Jens Hamisch
• Peter W. Osel
• John L. Furlan