I am answering this question as if quite newbie with perl. If you are not, please pardon this somewhat paternalistic post and do not take it as an attack. I'm just trying to help.

I came across some *.pf files recently that turned out to be "perl files".

Take a look at the beginning of the .pf files and look to see if they start with:
#!/<some path>/perl
or something similar. If they are, these are perl files with a different name
hackmare.