#!/usr/bin/perl

use strict;
use warnings;

my $dir = join(' ', map { '"'.$_.'"' } @ARGV) || "*"; # Use arguments or default to pwd
my @lines = qx(du -sc $dir);    # Get sizes in bytes, with total
my ($total) = split(/\s/, pop @lines);  # Get total number of bytes
foreach my $line (@lines) {
  if ($line =~ /(\d+)/) {
    printf("%6.2f%%\t%s", $1 * 100 / $total, $line); # Prefix %
  } 
}