for my $key( sort { $b <=> $a } keys %sizehash ) {
    # blah
}

##</code><code>##

for my $file( sort { $sizehash{$b} <=> $sizehash{$a} } keys %sizehash ) {
    my $size = commas($sizehash{$file});
  last if $y++ > 10;
    print "$size: $file\n";
}