First, well done for using strictures. They are going to help a lot in sorting out problems with your code as you develop it.

Your immediate issue is you need to add my in front of each variable when you first assign a value to it.

However, you have a long way to go to get your code complete. I suspect you haven't any chance to complete it within the time you have available. You should talk to your lecturer/tutor about the help you need.

We can give you some hints, but obviously just providing a solution is not going to help in the long run. Here are a few hints that will help write reliable software using Perl:

• Use indentation to clearly show nested blocks of code
• Use three parameter open and lexical file handles: open my $fIn, '<', $ruleFile or die "Can't open $ruleFile: $!\n";
• Use Perl's built in functions instead of executing command line tools. Perl's functions will work across most operating systems and are generally more robust against changes in the OS and shell.