title: What is file-descriptor?
body: <p>While trying to learn socket programming, I saw the following code:</p>
  <pre><code>int sock;
  sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  </code></pre>
  <p>I browsed through the man page and found that socket returns a file descriptor. I have tried searching the internet and other similar questions here but I couldn't understand what file descriptor really is. That would be great if someone could explain file descriptor in easy language.</p>