My best advice would be to put use CGI; at the beginning of your script.

More seriously, could you please explain why do you want to re-write a module which has proven itself to be stable, bug-free, reliable?

You may also want to look at Ovid's most excellent node dealing with the subject: use CGI or die;

Seriously, a lot of work went into CGI.pm and it comes with the core, so what's the problem with not using it?

This question has been debated at length on PM, so here is a list of related nodes:

• Re: Use of Modules: sums it up nicely
• Getting managers to accept Perl modules: a whole thread on the subject
• On Perl CPAN modules

just use the Search or Super Search to get more...

Update: fixed the first link, it sums it up much better now ;--) (thanks mischief)

I agree completely with Mssrs. mirod and OeufMayo. If you're doing any sort of real CGI work, use CGI.pm. In fact I think it's bordering on being professionally unethical to not use CGI.pm (or CGI::Lite) on a perl cgi job.

That said, if you're trying to re-write CGI.pm for your own education/amusement, there is no better source to see how things are done than looking at the source for ... CGI.pm!