The Environment Modules package provides for the dynamic modification
of a user's environment via modulefiles.

Each modulefile contains the information needed to configure the shell
for an application.

Once the Modules package is initialized, the environment can be modified
on a per-module basis using the module command which interprets
modulefiles. Typically modulefiles instruct the module command to alter
or set shell environment variables such as PATH, MANPATH, etc.
Modulefiles may be shared by many users on a system and users may have
their own collection to supplement or replace the shared modulefiles.

Modules are useful in managing different versions of applications.
Modules can also be bundled into metamodules that will load an entire
suite of different applications.