I would move all the calls to $cgi->param outside of the wanted sub. That is executed for every file being iterated on; probably not what you want to do.

Also, the only thing you're doing is checking if the CGI parameters are set, you're not doing anything with the files being iterated on. If you want to search for a string in the contents of each file, you'll have to open each file, then iterate on the file contents. Of course you'll want to do this only once per file, using open.

If I were doing it, I would probably construct a big regex based on the selected search options, and check for a match of that regex as I iterated on each file's contents. But you have some flexibility here. Maybe with a more specific question we can be of more use?