title: grep to replace strings in files iteratively on all subfolders, excluding some branches
body: <p>I'm trying to find out how to replace specific strings on all file of a directory and all the subfolders iteratively BUT excluding some subfoldes AND some file extensions. All at the same time.</p>
  
  <p>I've seen some examples of how to replace strings iteratively but cannot make it to have all this process in one single command.</p>
  
  <p>Any one knows? :)</p>
  
  <p>Thank you!!</p>