.. Home page

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
    /usr/local/gcc/6.3.1/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/6.3.1
    % which gcc
    /usr/local/gcc/6.3.1/linux-aarch64/bin/gcc

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

.. toctree::
   :hidden:
   :maxdepth: 2
   :caption: Installation

   INSTALL
   MIGRATING

.. toctree::
   :hidden:
   :maxdepth: 2
   :caption: Man pages

   module
   modulefile

.. toctree::
   :hidden:
   :maxdepth: 2
   :caption: Additional information

   diff_v3_v4
   FAQ
   NEWS
   cookbook
   CONTRIBUTING


License
-------

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