In your first link the best suggestion was from chromatic. Instead of thinking in terms of executing an external script, think in terms of calling a function. Both are methods of executing arbitrary code, but the advantage of a function is that it also has notions of how to pass arguments.

The alternative is to use global variables to do your communication. Global variables to communicate between a mass of scripts that call each other haphazardly is a short road to insanity. While it is the answer that you asked for, I strongly recommend not doing that. Write a module if you want your files to actually do something.

You may not have written a module before. If you haven't, it isn't as hard as people make it look. Take a look at Re (tilly) 1: Best way to fix a broken but functional program? for a random instance. Just save that template to a file whose name ends in ".pm", write a test script that uses it, then start adding, running, and testing. That template should serve you pretty well.