Perl is a scripting language run by the interpreter program - conveniently called 'perl'. So what you were doing was using your shell to run the perl interpreter and tell it which script to run. Alternatively, you can tell the shell which interpreter to use by putting the interpreter name inside the script. Do this by
having a line similar to as the first line of your script - replace /usr/bin/perl with the path to your perl interpreter if your system is different.

hope this helps