borisz,
I think the following recursive implementation does basically the same thing - don't ask me how I came up with it.

my @data = map {chomp; [ split '/' ] } <DATA>;
@data = map { join '/', @$_ } sort my_sort @data;

sub my_sort {
    my $i = shift || 0;
    if ( defined $a->[$i] && defined $b->[$i] ) {
        return $a->[$i] <=> $b->[$i] || my_sort(++$i);
    }
    return defined $a->[$i] ? 1 : -1;
}
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