title: Linux chmod command error: chmod: invalid mode:
body: <p>I want assign the privilege to directory app, my command as below：</p>
  
  <pre><code>sudo chmod -R hduser /app
  </code></pre>
  
  <p><code>hduser</code> is username in Linux, however, I got error message:</p>
  
  <blockquote>
    <p>chmod: invalid mode: `hduser'</p>
  </blockquote>
  
  <p>anything need update?</p>