my @arr = (
  { 'path' => '/c/', dir => '/' },
  { 'path' => '/c/a1.mp3', 'file' => 1, 'dir' => '/c' },
  { 'path' => '/c/a2.mp3', 'file' => 1, 'dir' => '/c' },
  { 'path' => '/c/bb/aa1.mp3', 'file' => 1, 'dir' => '/c/bb' },
  { 'path' => '/c/bb/aa2.mp3', 'file' => 1, 'dir' => '/c/bb' },
  { 'path' => '/c/bb/', 'dir' => '/c' },
  { 'path' => '/c/cc/', 'dir' => '/c' },
  { 'path' => '/c/aa/', 'dir' => '/c' }
);

@arr = sort sort_files @arr;
foreach (@arr) {
        my %h = %{$_};
        print $h{'path'}."\n";
}

# putting the folders on the top works, but... see output
sub sort_files {
        # if both in the same folder and one is folder, put it top
        if ($$a{'dir'} eq $$b{'dir'}) {
                if ($$a{'file'} && !$$b{'file'}) {
                        return 1;
                } elsif (!$$a{'file'} && $$b{'file'}) {
                        return -1;
                }
        }
        # compare
        lc $$a{'path'} cmp lc $$b{'path'};
}

##</code><code>##

/c/
/c/aa/
/c/bb/
/c/cc/
/c/a1.mp3      <<<< file! it should at the end of the list
/c/a2.mp3      <<<< file! should at the end of the list
/c/bb/aa1.mp3  <<<< this should be below /c/bb/
/c/bb/aa2.mp3  <<<< this should be below /c/bb/