Greetings,
Here are my thoughts on the current dilema.
Are you sure you want to do this test with regex?
I think index() might better serve your needs.
So the line in your original post

if (/$n_delim/){
[download]

would be rewritten as

if (index($_, $n_delim) != -1){
[download]

Seeing as you are not doing anything regexp specific with the value of $n_delim.
Hope that helps...

Peace and blessings to you all
-injunjoel