pngcrush script to run in a directory of pngs

crush.rb

#! /usr/bin/env ruby
#

Dir.glob("*.png") do |file|
  puts "crushing #{file}"
  file2 = file + '.cr'
  `pngcrush #{file} #{file2}`
  save = File.stat(file).size - File.stat(file2).size
  puts "  save #{save}"
  `mv #{file2} #{file}` 
end