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Module environment(Hawk)

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Revision as of 14:27, 14 January 2020 by Hpcbjdic (talk | contribs)
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Hints for users

A module environment is used on Hawk in order to allow for flexibly choosing software to be used out of a large set. In order to use a particular software, you first have to load the respective module. A set of default modules is already loaded after login.


A new implementation of the module command is used on Hawk in order to allow for improved user experience. However, the same sub-commands are available as known from former systems. The layout of outputs yet slightly differs. Furthermore, not all available modules are shown right after login (cf. below).


Basic commands:

  • show available modules: module avail or module avail <substring to be searched for>
  • show brief description for a given module: module whatis <modulename>
  • (un)load a module: module (un)load <modulename>
  • swap modules: module swap <old module> <new module>
  • show loaded modules: module list
  • show help for a specific module: module help <modulename>
  • search for keywords (e.g. “compiler”, “debugger”, etc.) in module descriptions: module keyword <keyword>


Please have a look on here w.r.t. further functionality.


In order to work properly, applications built with a given compiler and MPI need to be linked with libraries built with the very same compiler and MPI. The module mechanism deployed on Hawk supports you in doing so by providing only those modules built with the currently loaded compiler and MPI. In case of swapping the compiler and/or MPI, available and loaded modules are also swapped in order to match with the new compiler/MPI.


Right after login, you can load so-called system and core modules only. After loading a compiler, module avail shows also the modules depending on that compiler. In this set, you can - in particular - find MPI implementations. After loading one of those, module avail also shows the modules depending on the loaded compiler as well as MPI.
In order to list all available modules without considering their dependencies, use module spider. By passing a specific module to the module spider command, the system tells you which modules have to be loaded first in order to load the respective module.


Please have in mind:

  • It’s not allowed to have more than one version of a module loaded at a time. In particular, it’s not possible to have more than one compiler loaded at once. In case you need multiple compilers, please inspect the respective module files and set the required environment variables by your own.
  • If no version is specified, the module command picks the one with the highest version. If there are multiple modules with the same version, it picks the one found first while searching “from top to bottom” (w.r.t. to the output of module avail). In fact, the rule is more complicated. Please refer to https://lmod.readthedocs.io/en/latest/060_locating.html with respect to details.
  • All Bash scripts should start with #!/bin/bash, not #!/bin/sh, otherwise module command will not be available in the script!
  • We provide support for Bash only. In case of module command not being defined (correctly), cf. https://lmod.readthedocs.io/en/latest/030_installing.html#integrating-module-into-users-shells and https://lmod.readthedocs.io/en/latest/030_installing.html#issues-with-bash.
  • Do an export LMOD_PAGER=None to turn off displaying multi-page outputs with a pager (e.g. less).