Ruby search and replace across files

I am trying to write a ruby script which will look in a directory and its subdirectories for HTML files, open those HTML files and insert the following line just above the closing head tag:

<link rel="styl开发者_运维问答esheet" href="styles.css" type="text/css" />

I am trying to do this with Ruby because its the only language I am familar with but have access to pretty much any language. Could anyone lend a hand?

Cheers

Eef

def find_and_replace(dir)
  Dir[dir + '/*.html'].each do |name|
    File.open(name, 'r+') do |f|
      new_file = f.read.sub /^( *)(<\/\s*head>)/, %Q(\\1  <link rel="stylesheet" href="styles.css" type="text/css" />\n\\1\\2)
      f.truncate 0
      f.write new_file
    end
  end
  Dir[dir + '/*/'].each(&method(:find_and_replace))
end

find_and_replace '.'