title: Regex code for finding a URL containing and domain and adding a parameter
body: <p>Help! Needed for wordpress search and replace </p>
  
  <p>Have a bunch of links to amazon.com/productname/dp/productid or similar.</p>
  
  <p>Want to have a regex code that will search any URLs that contain amazon.com and end of the URL add the following "?tag=tagname"</p>
  
  <p>Thanks. </p>