bahadur:

Please do NOT replace an entire question with an (un-labeled) update, as you have done here.

Later readers may be able to infer the original question in this case, but generally, either add a plainly labeled update, or reply to a responder, so future visitors can follow the thread.

note to the (presumed) future reader: Loosely translated, and imperfectly recalled, bahadur sought wisdom on how to use the Getopt::Long module (had not discovered the pod, apparently) and questioned meaning of "module" with but a single function (as contrasted to C and java's multi-function counterparts)

You probably should stress my note above, "imperfectly recalled."