#!/usr/bin/perl -w
use strict;

my $dir = shift;

opendir DIR, $dir or die "Can't open $dir: $!";

foreach my $file ( grep /\.html|\.htm$/i, readdir DIR ) {
    ( my $newfile = $file ) =~ s/\.html|\.htm$/\.asp/i;
    rename "$dir\\$file", "$dir\\$newfile";
    print "Changing $dir\\$file to $newfile\n";
}

closedir DIR;