There are two configuration file use cases. Sometimes, we can stretch the definition slightly to add a third use case. The first two should be pretty clear:
- A person needs to edit a configuration file
- A piece of software will read a configuration file and make use of the options and arguments to tailor its behavior
Configuration files are rarely the primary input of an application program. Generally, they only tailor the program's behavior. For example, a web server's configuration file might tailor the behavior of the server, but the web requests are one primary input, and the database or filesystem is the other primary input. In the case of a GUI application, the user's interactive events are one input, and the files or database may be another input; a configuration file may fine-tune the application. The most notable exception...
