show file size in human readable format.

du.pl

#!/usr/bin/env perl
use warnings;
use strict;

die "Usage: $0 dir [dir dir ..]" if ($#ARGV<0);

sub filesize{
  my $s=shift || die "filesize: lack arguments";
  return "${s}B" if($s<10);
  my $i=$s;
  foreach my $a ('B','K','M','G','T','P','E','Z','Y'){
    return sprintf "%3.1f$a",$i if($i<10);
    return sprintf "%d$a",int($i) if($i<1024);
    $i/=1024;
  }
  return $s;
}

sub du{
  my $d=shift;
  my @a=`du -sb $d`;
  my %h;
  foreach (@a){
    my ($l,$n)=split;
    die "Error: $n already exist\n" if($h{$n});
    $h{$n}=$l;
  }
  return %h;
}

my %h=();
while(@ARGV){
  %h=(%h,&du(shift));
}

foreach my $name (sort {$h{$b}<=>$h{$a}} keys %h){
  printf "%5s %-30s\n", &filesize($h{$name}), $name;
}