crush.rb

#!/usr/bin/ruby

# from http://travis-whitton.blogspot.com/2009/10/crushing-pngs-with-ruby.html
# usage crush.rb images | sh

require 'fileutils'
require 'find'

input_dir = ARGV[0]
rewrite_dir = "/tmp/crush/"

raise("Usage #{$0} dirname") unless input_dir
Dir.mkdir(rewrite_dir) unless test(?d, rewrite_dir)

Find.find(input_dir) do |file|
  if file =~ /\.png$/
    base_dir = File.dirname(file)
    base_file = File.basename(file)
    new_dir = rewrite_dir + base_dir
    FileUtils.mkdir_p(new_dir) unless test(?d, new_dir)
    puts(%Q!pngcrush -reduce -brute "#{file}" "#{new_dir}/#{base_file}"!)
  end
end