Environment variables are dynamic values that influence the behavior of processes and applications on a computer. They configure system settings, manage paths to executable files and libraries, and store user-specific information such as home directories and shell preferences.

Users can customize their operating environment by setting or modifying environment variables in shell configuration files such as .bashrc or .bash_profile.

LMOD (Lua Modules) is a dynamic environment modules system used to manage environment variables for software applications and libraries. It simplifies the process of configuring the user environment by allowing users to load and unload modules that automatically set the required paths and environment variables.