sub get_by_glob {
    my @dids = map {/d([^\/]+)$/; $1} csh_glob("$path/d[0-9]*/d[0-9]*");
    return \@dids;
}

sub get_by_open
{
    opendir(my $dh, $path);
    my(@top) = grep(/^d/, readdir($dh));
    closedir($dh);
    my(@dids)=();
    foreach my $sd (@top){
        opendir(my $sh, $path.'/'.$sd.'/');
        push @dids, map({m/d(\d+)$/} readdir($sh));
        closedir($sh);
    }
    return \@dids;
}