#!/usr/bin/perl

use File::Find;

die "Usage $0 <dir> <int_files_to_show>\n" if $ARGV[0] =~ m/-h/;

my $dir = $ARGV[0] || '.';
my $num = $ARGV[1] || 20;     # how many files to print
my %h;

find( sub { -f and $h{$File::Find::name} = -s }, $dir );

for ( sort { $h{$b} <=> $h{$a} } keys %h ) {
    printf "%s\t%s\n", add_commas($h{$_}), $_;
  last if --$num == 0;
}

sub add_commas {
    my ( $number ) = @_;
  return undef unless $number;
    ( $number, my $dec ) = $number =~ m!([+-]?\d+)\.?(\d*)!;
  return undef unless $number;
    $number =~ s/(\d)(?=(\d{3})+(\D|$))/$1,/g if length($number) > 3;
  return $dec ? "$number.$dec" : $number;
}