title: How to check which PHP extensions have been enabled/disabled in Ubuntu Linux 12.04 LTS?
body: <p>I'm using Ubuntu Linux 12.04 LTS on my local machine. I've installed LAMP long ago on my machine. Now I want to enable following PHP extensions:</p>
  
  <ol>
  <li>php_zip</li>
  <li>php_xml</li>
  <li>php_gd2</li>
  </ol>
  
  <p>For it first I want to check whether these PHP extensions are enabled or not. I searched a lot about how to check the installed/enabled PHP extensions but every time I found how to install these extensions on Ubuntu Linux. So can someone please let me know how should I check the enabled/disabled PHP extensions in Ubuntu Linux 12.04 LTS? Thanks in advance.</p>