my $dupes = 0;
    while (<FH1>) {
        chomp;
        my ($var1,$var2) = split(/:/,$_);
        $var2 = substr($var2,1); #remove 1st space results from substr

        # here is the important bit:
        if (exists $diffHash1{$var2})
        {
          ++$dupes;
          print "Dupe on line $.: $var2\n";
        }

        $diffHash1{$var2} = $var2;
    }
    print "$dupes dupes found in file1.\n";