getEnv package:base

Computation getEnv var returns the value of the environment variable var. For the inverse, the setEnv function can be used. This computation may fail with:
Similar to lookupEnv.
getEnvironment retrieves the entire environment as a list of (key,value) pairs. If an environment entry does not contain an '=' character, the key is the whole entry and the value is the empty string.
Get an environment value or a default value.