title: PHP Codeigniter error failed to open stream: Permission denied
body: <p>I have been working on a project that uses codeigninter. I worked on it in Windows 7 and it was fine but after I moved this project on Ubuntu to work on it there, It gives me this error in every page/controller/method that I try to access:</p>
  
  <pre><code>Warning: require_once(/opt/lampp/htdocs/TS_Project/system/core/CodeIgniter.php): failed to open stream: Permission denied in /opt/lampp/htdocs/TS_Project/index.php on line 202
  
  Fatal error: require_once(): Failed opening required '/opt/lampp/htdocs/TS_Project/system/core/CodeIgniter.php' (include_path='.:/opt/lampp/lib/php') in /opt/lampp/htdocs/TS_Project/index.php on line 202
  </code></pre>
  
  <p>The <code>CodeIgniter.php</code> file does exist, the path to it is correct and I am able to read and write in it ( I can open it in a text editor and modify it freely). I tried changing the file permission to it using the <code>chmod</code> command but nothing happens. Why is permission denied to the <code>CodeIgniter.php</code> file?</p>