Earlier quoted context omitted.
"I find nothing" is a fairly strong statement. There are plenty of general purpose scripts one can write in PHP. Also config files don't preclude 'general purpose'. For example, run anything in Java and you'll find out there are plenty of defaults running on the JVM that you can override. Yet no one would argue Java isn't a general purpose language. The fact that PHP keeps these defaults in a file is inconsequential.
How is that a fairly strong statement? Here's a much stronger one: PHP is terrible at being a general purpose language. General purpose language doesn't mean you can do things that aren't web dev in it. General purpose means that it is designed to be useful in any application. You know like Ruby, Python, or Perl. General purpose doesn't mean that those things are possible (because I agree that they are possible in PH…
More concretely- what's an easy non-web task that Ruby (as you suggest learning) is great at that PHP can't handle just as easily? Not trolling here, I'm genuinely curious.