How to create modulefile for linux Environment Modules?

Question

How to create modulefile on centos7 for any software (ex. for python)?

path of modulefile is /etc/modulefile

I have two version of python ( python2.7 and python3.7).

I Create a directory for python inside modulefiles /etc/modulefiles/python , then I shoud create a modulefiles for paython as a following code :

#%Module 1.0
# python2.7 module file

conflict        python
prepend-path  PATH              ---
prepend-path  LD_LIBRARY_PATH   ----
prepend-path  MANPATH           ---
prepend-path  INFOPATH          ---

setenv        --_DIR            ---
setenv        --_BIN            ---
setenv        --_INC            ---
setenv        --_LIB            --- 

My question is how can I get the right variables of prepend-path and setenv

Below is result of whereis python command, can we extract varable of prepend-path and setenv from it:

[root@mu modulefiles]# whereis python
python: /usr/bin/python /usr/bin/python2.7 /usr/bin/python2.7-config /usr/lib/python2.7 /usr/lib64/python2.7 /etc/python /usr/local/bin/python3.7m-config /usr/local/bin/python3.7m /usr/local/bin/python3.7 /usr/local/lib/python3.7 /usr/include/python2.7 /etc/modulefiles/python /usr/share/man/man1/python.1.gz

Answer 1

The PATH variable is the environment variable used to search for binaries. You installed two different versions of Python, so each should have a different directory containing the python executable (bin and probably also extra/bin).

The LD_LIBRARY_PATH is used to list the directories containing libraries. Probably lib and extra/lib, etc.

There are more environment variables that can be set, depending on the module you are trying to create. For instance, a gcc module will probably set the CC environment variable. Python can also have PYTHONPATH where Python will look for modules and packages.

The MANPATH environment variable is used to look for man pages whereas the INFOPATH is used to find Info manuals.

The variables that you need to set depend exclusively on what you actually want to use. It can be enough to just update PATH and never update the MANPATH properly, for example.