I couldn't find a CPAN script called top - but hypothetically if one exists and does broadly what unix top does: I would say: a script that produces data on top-consuming processes is not as valuable in the longer run as a module that can be inherited and locally augmented to monitor additional information about the processes or to filter the processes on different criteria, e.g. I/O instead of CPU, than what top does - a script has a limited application, a module has no limit.