If you remember that your "CGI script" is just another fancy word for a Perl program, you will understand that you can just execute your Perl program (either on the command line or through a dedicated editor (Komodo springs to mind as it has a special feature to allow easy feeding of your script with CGI parameters) and see its output. If the output if HTML, some editors can capture it and render it as a browser would do (again (Komodo is able to do so).

CountZero

"If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law