Oops - ignore my previously reply. I also thought it was "how to extract variables" as the problem

Setting some files in the root directory of an Apache installation as executable, and others not, other than based on extension, is, as far as I can remember, exceptionally difficult.

Your best bet is to either put the file in a subdirectory where you can make every file an executable, or, if you can (i.e you don't have any files needing served as pure HTML), mark all files as executables through setting a PerlHandler Apache::Registry on / (assuming you're just going to use the Registry, rather than write your own handler...)

Tony