What are 3 types of environment variables in Linux shell?

[zayn_william Member Find all posts View Profile Close zayn_william]

Hello Everyone,
I am studying Linux variables and I would like to know about Linux environment variables and their types.

[Christian J Member Find all posts View Profile Close Christian J]

In Linux, environment variables are values accessed by processes and programs launched from the shell. They define various aspects of the environment where the shell and its child processes operate.

In the Linux shell, there are three types of environment variables:

1. System Environment Variables: The operating system sets these variables, which are available to all users and processes. Examples include PATH, HOME, and USER.
2. User Environment Variables: Users can set these variables to specify the default editor, shell, or aliases for their own processes.
3. Shell Environment Variables: Shell variables control the behavior of the shell, including prompt appearance, history settings, and input/output.