Well there's an entry point of course, but it shouldn't know much. Your entry point knows about your option parser which knows about the high-level actions your

Well there's an entry point of course, but it shouldn't know much. Your entry point knows about your option parser which knows about the high-level actions your program performs which know about the sub-processes involved in accomplishing them, etc. It's important to keep this graph as acyclic as possible, and to try not to have any one component directly interact with too many other components, because then your abstraction is too fragile.