title: Regular Expression for email subdomain match
body: <p>Anyone know of a regular expression that will only match emails that contain a sub-domain in them?</p>
  
  <p><strong>e.g.,</strong></p>
  
  <p><code>name@subdomain.domain.com</code> or <code>name@subdomain.domain.edu.au</code></p>
  
  <p>Preferably to use in <a href="/questions/tagged/postgresql" class="post-tag" title="show questions tagged 'postgresql'" rel="tag">postgresql</a>.</p>
  
  <p><strong>I tried this:</strong></p>
  
  <pre><code>^[-+.0-9A-Z_a-z]+@[-+.0-9A-Z_a-z]+\.[A-Za-z]{2,4}$
  </code></pre>
  
  <p>but it also matches <code>name@test.org</code>.</p>