I seriously doubt there is anything you have written that is worthy of needing such "closing". And if there truly is, then you should be writing a paper ( or even book ) about it, speaking on it and then getting massive contracts because somebody saw your brilliant piece of Perl code -- they can't do that if it is "closed".
I second that opinion. I've worked with some pretty big systems in my work life so far...the better/more flexible ones provided source code and/or scripting facilities of some kind.
Chris