[mod4 (modulepath)]$ module purge
[mod4 (modulepath)]$ module load foo
ERROR: Unable to locate a modulefile for 'foo'
[mod4 (modulepath)]$ module load gcc/8.2.0
[mod4 (modulepath)]$ module load foo
[mod4 (modulepath)]$ module list
Currently Loaded Modulefiles:
 1) gcc/8.2.0   2) foo/1.1
[mod4 (modulepath)]$ foo
foo 1.1 (gcc/8.2.0, nompi)
[mod4 (modulepath)]$ module purge
[mod4 (modulepath)]$ module load gcc/8.2.0
[mod4 (modulepath)]$ module load openmpi
[mod4 (modulepath)]$ module load foo
[mod4 (modulepath)]$ module list
Currently Loaded Modulefiles:
 1) gcc/8.2.0   2) openmpi/3.1   3) foo/1.1
[mod4 (modulepath)]$ foo
foo 1.1 (gcc/8.2.0, openmpi/3.1)
[mod4 (modulepath)]$ module purge
[mod4 (modulepath)]$ module load foo/1.1
ERROR: Unable to locate a modulefile for 'foo/1.1'
[mod4 (modulepath)]$ module list
No Modulefiles Currently Loaded.
[mod4 (modulepath)]$ module purge
[mod4 (modulepath)]$ module load pgi/18.4
[mod4 (modulepath)]$ module load foo
[mod4 (modulepath)]$ module list
Currently Loaded Modulefiles:
 1) pgi/18.4   2) foo/1.1
[mod4 (modulepath)]$ foo
foo 1.1 (pgi/18.4, nompi)