title: How can I append RSS data to the existing RSS XML file?
body: <p>I have an RSS data XML file existing on the folder. I have to append new data to the RSS XML file. I need to do it with PHP only. I have rss data (item, title, url, desc) coming from web service. I have to append to the existing rss xml file which has previous data.</p>
  
  <p>RSS data format is like this</p>
  
  <pre><code> &lt;rss version="2.0"&gt;
    &lt;channel&gt;
      &lt;title&gt;My Site Feed&lt;/title&gt;
      &lt;link&gt;http://www.mysitethathasfeed.com/feed/&lt;/link&gt;
      &lt;description&gt;
          A nice site that features a feed.
      &lt;/description&gt;
      &lt;item&gt;
          &lt;title&gt;Launched!&lt;/title&gt;
          &lt;link&gt;http://www.mysitethathasfeed.com/feed/view.php?ID=launched&lt;/link&gt;
          &lt;description&gt;
             We just launched the site! Come join the celebration!
          &lt;/description&gt;
      &lt;/item&gt;
    &lt;/channel&gt;
  &lt;/rss&gt;
  </code></pre>
  
  <p>I want to add another item dynamically a using PHP only. How can I do that? </p>