retrieve_css_imgs.rb

#!/usr/bin/ruby

url = ARGV[0]
css_file = ARGV[1]
strip = ARGV[2]

File.open(css_file, 'r') do |f|
  while line = f.gets do
    match = line.match(/url\((.*?)\)/)
    if match
      file = match[1]
      file = file[strip.size..-1] if !strip.nil? and file =~ /^#{strip}/
      `wget #{url}/#{file}`
    end
  end
end