Perl was super for little scripts hence it became popular. I think the killer feature was its fantastic regular expression language which beat everything at the time. All other languages had to do to was neutralise that one advantage and they did.
Perl was horrible to build, IMO, and seemed to require 100s of options to be selected which would mean that some script would or would not run with that particular build of Perl depending on what you chose.
Python had a more clunky but still excellent regexp package, it was a doddle to build and most of the things that affected compatibility were things you could install after the python executable was built and installed - i.e. users could get their code to work more reliably.