title: How to add a line of text containing the filename to all text files recursively in terminal?
body: <p>I have a bunch of javascript files and I need to add a comment on a new line at the beginning of every file that contains the filename e.g.</p>
  
  <pre><code>/* app.js */
  </code></pre>
  
  <p>I'd like to do this recursively on a folder from the terminal on my mac.</p>
  
  <p>Can anyone help?</p>
  
  <p>Thanks!</p>