Error Finder - Simple Ruby site crawler, finds non-200 response codes

error_finder.rb

#!/usr/bin/env ruby

# Simple non-200 finder, for finding errors and redirects

require 'rubygems'
require 'anemone'

url = ARGV[0]

if url.nil?
  puts "Usage: error_finder.rb http://example.com"
  exit
end

Anemone.crawl(url) do |anemone|
  anemone.on_every_page do |page|
    if !page.code.nil? and page.code > 200
      puts "[#{page.code}] #{page.url} - Referrer: #{page.referer}"
    end
  end
end