I used this on linux and it works exactly as indicated, eg. "./test.p sort" produced:

sort in /home/me/perl/*.pl:
        6 -- big.II.pl
        4 -- big.pl
        1 -- sortoccurances.pl
        1 -- example3.pl
        1 -- test.pl
[download]

Nb. toolic "if ($this =~ /$bit/)" never was inside the while loop! I am sure that would be a problem. I am also sure from reading halfcountplus's other posts (ranking number of occurances) that slurping the entire file is intentional (how else could this work?). However, if i got an error, i would be suspicious too.

Perhaps if you replace the "/" with a "\" (line 20)?