An environment file is a script that:
Loads software libraries into your login environment. This is often done with a module manager such as lmod, spack, or environment-modules.
Stores settings for GEOS-Chem and its dependent libraries in shell variables called environment variables.
You will source the environment file each time you log in with a command such as:
$ . ~/my-environment-file # or whatever you name it
Keep a separate environment file for each combination of modules that you will use. Example environment files for GNU and Intel compilers and related software are provided in the following sections.
For general information about how libraries are loaded, see Load required libraries.