Environment Modules (software): Difference between revisions

Revision as of 12:53, 12 January 2025

Revision as of 15:03, 12 January 2025

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{{Short description|Tool for dynamic modification of a user's shell environment during a session}}

{{how-to|date=February 2015}}

{{Infobox software

| name = Environment Modules

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| operating_system = [[Unix-like]]

| license = [[GNU General Public License#Version 2]]

| website = {{URL|httphttps://modules.sourceforge.net/}}

}}

The '''Environment Modules''' system is a tool to help users manage their [[Unix]] or [[Linux]] shell environment, by allowing groups of related environment-variable settings to be made or removed dynamically.

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The modules system is based on modulefiles,<ref>{{cite web |url=http://modules.sourceforge.net/man/modulefile.html |title=modulefile - files containing Tcl code for the Modules package |author=John L. Furlani & Peter W. Osel |date=July 2009 |website=SourceForge |publisher=man page |access-date=9 February 2014}}</ref> which specify groups of environment settings that need to be made together. Modulefiles can be installed in a central ___location for general use, or in a user directory for personal use. Environment Modules modulefiles are written in the [[Tcl| Tcl (Tool Command Language)]] and are interpreted by the modulecmd program via the module<ref>{{cite web |url=http://modules.sourceforge.net/man/module.html |title=module - command interface to the Modules package |author=John L. Furlani & Peter W. Osel |date=July 2009 |website=SourceForge |publisher=man page |access-date=9 February 2014}}</ref> user interface.

The key advantage of Environment Modules is that it is shell independent and supports all major shells such as [[Bash (Unix shell)|bash]], [[KornShell|ksh]], [[Z shell|zsh]], sh, [[tcsh]], and [[C shell|csh]]. The second key advantage is that it allows to use multiple versions of the program or package from the same account by just loading proper module. Those two advantages were instrumental in making Environment Modules a part of most HPC cluster setups. It also inspired several alternative implementation such as lmod from University of Texas, which is written in [[Lua (programming language)|Lua]] instead of TCL[[Tcl]].

modulefiles are created on per application per version basis. They can be dynamically loaded, unloaded, or switched. Along with the capability of using multiple versions of the same software it also can be used to implement site policies regarding the access and use of applications.

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The {{mono|${MODULESHOME}/modulefiles/'''use.own'''}} module essentially performs these steps:

{{sxhl|2=bash|

mkdir $HOME/privatemodules

cp ${MODULESHOME}/modulefiles/null $HOME/privatemodules

module use --append $HOME/privatemodules

}}

=== Use a version file within a hierarchical organization ===

The commands in this section require read/write/execute access to the {{Mono|/etc/modulefiles}} directory. The {{Mono|$HOME/privatemodules}} or another directory can be used instead along with "{{Mono|module use --append}}" or modification of the configuration file specifying the default modules search path.

The default {{Mono|modulefiles}} directory is empty initially. Copy the null module to the default modulefiles directory to have it shown by "module avail". The following uses the null and module-info modules to show use of a version file within a hierarchical organization and their effect on module avail and module show:

<syntaxhighlight lang="bash">

mkdir /etc/modulefiles/test

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module show test

</syntaxhighlight>

Set the first version as the default:

<syntaxhighlight lang="bash">

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module show test/2.0

</syntaxhighlight>

Switch to the newer version as the default with:

<syntaxhighlight lang="bash">

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module show test

</syntaxhighlight>

After the above following a fresh install from source you would see:

<syntaxhighlight lang="console">

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== Automatic modules initialization ==

Environment Modules on [[Scientific Linux]], [[CentOS]], and RHEL[[Red Hat Enterprise Linux]] distributions in the environment-modules package include {{mono|modules.csh}} and {{mono|modules.sh}} scripts for the {{mono|/etc/profile.d}} directory that make modules initialization part of the default shell initialization. One of the advantages of Environment Modules is a single modulefile that supports bash, ksh, zsh, sh as well as tcsh and csh shell users for environment setup and initialization. This makes managing complex environments a bit less complicated.

For a source build the automation for all users can be manually configured.

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{{mono|/etc/profile.d/modules.sh}} from the {{mono|etc/global/profile.modules}} file in the 3.2.10 modules build directory.

<syntaxhighlight lang="bash">

trap "" 1 2 3

case "$0" in

-bash|bash|*/bash) . /usr/local/Modules/default/init/bash ;;

-ksh|ksh|*/ksh) . /usr/local/Modules/default/init/ksh ;;

-zsh|zsh|*/zsh) . /usr/local/Modules/default/init/zsh ;;

*) . /usr/local/Modules/default/init/sh ;; # default

esac

trap 1 2 3

</syntaxhighlight>

Copy the {{mono|etc/global/profile.modules}} file from the 3.2.10 modules build directory to the system initialization directory:

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On Scientific Linux, CentOS, and RHEL distributions Environment Modules is in the environment-modules package which can be installed with:

<syntaxhighlight lang="console">

$ sudo yum install environment-modules

</syntaxhighlight>

Once installed the package information can be viewed with:

<syntaxhighlight lang="console">

rpm -qi environment-modules

$ rpm -qlqi environment-modules

$ rpm -qiql environment-modules

</syntaxhighlight>

=== Installing Environment Modules on Linux using apt and dpkg ===

On Ubuntu or systems using {{Mono|apt-get}}, Environment Modules can be installed with:

<syntaxhighlight lang="console">

$ sudo apt-get install environment-modules

</syntaxhighlight>

Once installed the package information can be viewed with:

<syntaxhighlight lang="console">

$ dpkg -L environment-modules

</syntaxhighlight>

=== Installing Environment Modules on Linux from source ===

Although installing from a Linux distributions repository using that distributions update manager is the easiest the software can be installed from source. Resolve dependencies is the most difficult task for an installation from source. The typical configure, make, install cycle can become painfully slow as each configure improvement reveals another dependency not available in your default environment. This section includes the steps to install the Environment Modules package on source including compiling the [[Tcl| Tcl (Tool Command Language)]] from source as a dependency.

* [http://nickgeoghegan.net/linux/installing-environment-modules Installing Environment Modules]

==== 8.6.1 version of [[Tcl| Tcl (Tool Command Language)]] built from {{Mono|/usr/local/src}} ====

Although the PCLinuxOS 64-bit repositories include [[Tcl| Tcl (Tool Command Language)]] they do not include a development package with the configuration files required to build Environment Modules on Linux from source. Building [[Tcl]] from source will make the required files available.

Tcl Sourcesource code: http://sourceforge.net/projects/tcl/files/Tcl/

Extract source after downloading

{{sxhl|2=bash|

cd /usr/local/src

tar -xvzf ~/Downloads/tcl8.6.1-src.tar.gz

}}

Configure, make, install

{{sxhl|2=bash|

cd /usr/local/src/tcl8.6.1

unix/configure

make

sudo make install

}}

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Extract source after downloading

{{sxhl|2=bash|

cd /usr/local/src

tar -xvzf ~/Downloads/modules-3.2.10.tar.gz

}}

Configure, make, install

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== See also ==

{{Portal|Free and open-source software}}

* [[Tcl]]

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== External links ==

* http{{Official website|https://modules.sourceforge.net/ - home page for the Environment Modules project}}

* John L. Furlani, [http://modules.sourceforge.net/docs/Modules-Paper.pdf Modules: Providing a Flexible User Environment] ''Proceedings of the Fifth Large Installation Systems Administration Conference (LISA V)'', pp.&nbsp;141–152, San Diego, CA, September 30 - October 3, 1991.

* http://lmod.sourceforge.net - alternative implementation using LUA instead of Tcl