Environment Modules is a system to manage what software is loaded into your environment.

It includes the ability to list all software packages currently available in the Modules system, load new software package into your environment, list all loaded software packages, and unload packages.

We use this system, rather than simply including all software in your default PATH, as it permits us to offer alternate versions of the same software, or to provide packages which might normally interfere with each other.

Find what packages are available

abcd@lemming> module avail

------------------------------------------ /usr/share/Modules/modulefiles -------------------------------------------
dot         module-git  module-info modules     null        use.own

------------------------------------------------- /etc/modulefiles --------------------------------------------------
compat-openmpi-psm-x86_64 matlab/2014a          sm/2.4.36
compat-openmpi-x86_64     matlab/2015a          tecplot/10.0
ds9/7.3.2                 openmpi-x86_64        texlive/2013
--------------------------------------- /usr/local/share/Modules/modulefiles ----------------------------------------
ds9/7.3.2       idl/8.3            mathematica/10.2  matlab/2014a       scisoft/7.7        tecplot/10.0
fastx/1.0-39    intelcce/12.1.3    mathematica/8.0   matlab/2015a       skype/4.3          tecplot/2015r2
idl/8.1         mathematica/10.0.2 mathematica/9.0   scisoft/7.5        sm/2.4.36          texlive/2013

Or (perhaps more useful):

[1170]abcd@lemming ~> module whatis
dot                  : adds `.' to your PATH environment variable
module-git           : get this version of the module sources from SourceForge.net
module-info          : returns all various module-info values
modules              : loads the modules environment
null                 : does absolutely nothing
use.own              : adds your own modulefiles directory to MODULEPATH
ds9/7.3.2            : adds SAOImage DS9 (7.3.2) to your environment
matlab/2014a         : adds Matlab 2014a to your environment
matlab/2015a         : adds Matlab 2015a to your environment
sm/2.4.36            : adds SM (2.4.36) to your environment
tecplot/10.0         : adds Tecplot 10.0 to your environment
texlive/2013         : adds TeXLive 2013 to your environment
ds9/7.3.2            : adds SAOImage DS9 (7.3.2) to your environment
fastx/1.0-39         : adds StarNet FastX 1.0-39 to your environment
idl/8.1              : adds IDL 8.1 to your environment
idl/8.3              : adds IDL 8.3 to your environment
intelcce/12.1.3      : adds Intel C/C++/Fortran compilers (12.1.3) to your environment
mathematica/10.0.2   : adds Mathematica 10.0.2 to your environment
mathematica/10.2     : adds Mathematica 10.2 to your environment
mathematica/8.0      : adds Mathematica 8.0 to your environment
mathematica/9.0      : adds Mathematica 9.0 to your environment
matlab/2014a         : adds Matlab 2014a to your environment
matlab/2015a         : adds Matlab 2015a to your environment
scisoft/7.5          : adds Scisoft 7.5 to your environment
scisoft/7.7          : adds Scisoft 7.7 to your environment
skype/4.3            : adds skype v4.3 to your environment
sm/2.4.36            : adds SM (2.4.36) to your environment
tecplot/10.0         : adds Tecplot 10.0 to your environment
tecplot/2015r2       : adds Tecplot 2015 r2 to your environment
texlive/2013         : adds TeXLive 2013 to your environment

The command for loading a package into your environment is module load <package name>. This loads the most recent version of the package. For example

module load idl

If a specific version of a package is desired, the command can be expanded to module load <package name>/<package version>. For example:

module load mathematica/9.0

To see what packages are currently loaded, the command is module list.

abcd@lemming> module list
Currently Loaded Modulefiles:
  1) sm/2.4.36

The command to unload a package is module unload <package name>. This command will also remove any prerequisites for the package being removed.

The previous changes will allow you to manage your environment in the current shell environment, but will not affect other shells, or new shells. Thus running something like mpirun may not capture these settings, since the new shells spawned by mpirun may not get the same environment as the original shell.

To manage your default environment through modules, begin by adding to the end of your ~/.bashrc or ~/.cshrc startup script the line

module load null

The “null” module actually does nothing in and of itself; it merely provides a placeholder for the following commands to operate on.

Next, to add a module to your default environment, use the command

module initadd [module name]

This will alter the “module load” line in your startup script to load this module at each shell invocation. In this way you can manage your default environment through the modules package without editing your startup scripts.

To disable a default module, use “initrm”

module initrm [module name]

This removes that module from the module line in your startup script.