Using “module” command

The module command is used to load environment for various software, like compilers, MPI libreries etc.

The module command will let you load and unload the environment needed to run specific applications or use specific libraries. It is especially useful when you need to have different versions of the same software/library or the same software/library compiled against different compilers.

In our cluster, for instance, we have both GNU and Intel compilers, therefore, in order to use MPI when we compile using one of those compilers we need to have two different versions of OpenMPI, but instead of having binaries name like mpicc-1.4.3-intel-11.1 or similar we use module to update the PATH environment variable, so that after loading the specific module for openmpi/intel we will just run mpicc and mpirun.

HOWTO

The syntax of the module command is the following:

    module <subcommand> [<arguments>]

<subcommand> may or may not require one or more <arguments>

A partial list of available subcommands follows:

list to list the currently loaded modules,
avail to list all the available modules
load to load one or more modules
unload to unload one or more modules
purge to unload all the currently loaded modules

A detailed list of all subcommands is shown by running the command module help

The output of the module avail command could be something like:

$ module avail

---------------- /opt-ictp/ohpc/modulefiles/mpi ----------------
 gnu-openmpi/boost/1.63.0
 gnu-openmpi/fftw/3.3.4
 gnu-openmpi/netcdf-cxx/4.3.0
 gnu-openmpi/netcdf-fortran/4.4.4
 gnu-openmpi/netcdf/4.4.1.1
 gnu-openmpi/phdf5/1.8.17
 gnu-openmpi/scalapack/2.0.2
 gnu-openmpi/scipy/0.19.0
 intel-mpi/2016
 openmpi/1.10.2/intel/2013
 openmpi/1.10.2/intel/2016
 openmpi/1.10.2/intel/2017        (D)
 openmpi/1.6.5/intel/2013
 openmpi/gnu
 openmpi/intel

--------------- /opt-ictp/ohpc/modulefiles/libs ----------------
 boost/1.55
 boost/1.60                  (D)
 cln/1.3.2
 esmf/7.0.0
 gabriel/1.2
 gmp/4.3.2/default-compiler
 gmp/default-compiler
 grib_api/intel              (D)
 grib_api/1.12.0/intel
 grib_api/1.23.1/intel
 hdf5/intel                  (D)
 hdf5/1.8.12/intel
 hdf5/1.8.19/intel
 iml/1.0.3/gnu/4.4.0
 intel-mkl/2017
 mpc/0.9/default-compiler
 mpc/default-compiler
 mpfr/3.0.0/default-compiler
 mpfr/default-compiler
 netcdf/intel                (D)
 netcdf/4.3.1/intel/2013
 netcdf/4.4.1/intel/2017
 plasma/2.6.0

------------- /opt-ictp/ohpc/modulefiles/compilers -------------
 cuda/5.5                intel/2013       (D)
 cuda/6.5                intel/2016
 cuda/9.1         (D)    intel/2017
 default-compiler        nocomp
 g++_addon/4.9.0         opencl-amd
 gcc/4.4.7               opencl-intel
 gcc/4.5.2               opencl/amd/2.8
 gcc/4.6.2               opencl/intel/1.2
 gcc/4.9.0        (D)    pgi/10.9
 gnat/2014               pgi/16.10        (D)
 gnu/5.4.0               pgi/18.4
 gnu7/7.2.0

--------------- /opt-ictp/ohpc/modulefiles/apps ----------------
 PHCpack/2.3.95
 R/2.15                          (D)
 R/3.1.2
 R/3.3.1
 R/3.5.1
 alps/2.1.1
 anaconda3/5.1.0
 cdo/1.9.0
 cp2k/2.4                        (D)
 cp2k/2.6.1
 espresso/5.1                    (D)
 espresso/5.2.1
 espresso/6.2.1
 ferret/v6.842
 gdal/1.7.3
 gdal/2.2.4
 gdal/2.3.0
 gdal/2.3.1                      (D)
 gdl/0.9.4/intel
 gengetopt/2.22/default-compiler
 glpk/4.45/gnu/4.4.0
 gnu/gsl/2.2.1
 gnu/hdf5/1.8.17
 gnu/numpy/1.11.1
 gnu/openblas/0.2.19
 gnu/openmpi/1.10.6
 grads/binary
 gromacs/2016.3
 lhapdf/5.8.6/default-compiler
 maple/14
 matlab/r2011
 ncl/5.2.1/gnu/4.4.7
 ncl/6.0.0/gnu/4.4.7
 ncl/6.3.0/gnu/4.4.7
 nco/intel                       (D)
 nco/4.4.2/intel
 nco/4.6.8/intel
 nwchem/6.5
 proj/4.7.0
 proj/5.1.0                      (D)
 python/esp
 python/2.7.13                   (D)
 root/5.30.04/default-compiler
 root/6.08.06

------------------ /opt/ohpc/pub/modulefiles -------------------
 autotools        (L)    gnu7/7.2.0         papi/5.5.1
 clustershell/1.8        llvm4/4.0.1        pmix/1.2.3
 cmake/3.9.2             llvm5/5.0.0        prun/1.1
 gnu/5.4.0               ohpc        (L)    prun/1.2   (L,D)

 Where:
 D:  Default Module
 L:  Module is loaded

The syntax used for module names is usually:program_name/program_version/compiler_name/compiler_version.

To load, e.g., the openmpi module for the intel compiler you can then run module load openmpi/intel. If you then run the command module list you will see:

$ module load openmpi/intel

$ module list
Currently Loaded Modulefiles:
1) intel/2013 2) openmpi/intel

as expected, the intel module has been loaded automatically since openmpi requires it.