Nice first post. (: I liked the completely different approach and I liked the way you did it.

I thought you might appreciate another alternative for the final part:

@cellsites =
    grep { my $age= $spd * -M $dir.$_;
        $age <= $yes  &&  $morning <= $age
    } readdir CELLSITES;
[download]

which I think is a slight improvement. Keep up the good work.

        - tye (but my friends call me "Tye")