open PIPE, sprintf("du -s %s/* |,$FILESYSTEM) or die $!;
my @raw=<PIPE>;
chomp @raw;
my @summary=();
foreach my $line(@raw){
        my($blocks,$subdir)=split(/[\s+]/,$line);
        push @summary,{
                        blocks=>$blocks,
                        subdir=>$subdir
        };
}

@summary=sort {
                $b->{blocks} <=> $a->{blocks}
        } @summary;

printf "%s\n",join("\n",
        map { 
                sprintf("%d\t%s",$_->{blocks},$_->{subdir})
        } @summary[0..19]
        );