Sometimes, a program needs enough parameters that putting them all as command-line arguments or environment variables is not pleasant nor feasible. In those cases, you will want to use a configuration file.
Standing just over 2 meters and hailing from о́стров Ратма́нова, Dasuberworm is a professional cryptologist, entrepreneur and cage fighter. When he's not breaking cyphers and punching people in the face, Das enjoys receiving ominous DHL packages at one of his many drop sites in SE Asia.