gistfile1.rb

#!/usr/bin/env ruby

# Sort entries by content size. Usage:
#   sortbysize [<directory>='.']
#
# This script is documented at:
#   http://roman.flucti.com/sorting-directories-by-content-size-with-ruby
#

class Entry < Struct.new(:size, :unit, :name)
  UNITS = %w(B K M G T P)
  FORMAT = /^(.+)(#{UNITS * '|'})\t+(.+)$/
  
  def self.parse_list(du_output)
    du_output.split($/).map { |line| Entry.parse(line) }.compact
  end
  
  def self.parse(line)
    return unless line =~ FORMAT
    new($1.to_f, $2, $3)
  end

  def <=>(other)
    return unless self.class === other
    comparable <=> other.comparable
  end
  
  def to_s
    "%6s%s %s" % [size, unit, name]
  end
  
protected

  def comparable
    [UNITS.index(unit), size, name]
  end
end

Dir.chdir(ARGV.first || '.') do
  puts Entry.parse_list(`du -sh *`).sort.reverse
end