title: How to search for a particular text using perl regex?
body: <p>Among the following strings listed below, I only need to search the first string..</p>
  
  <pre><code>  test A             &lt;--- only need this string
    test A and test B  &lt;--- don't need this string
    test A and test C  &lt;--- don't need this string
    test A and test D  &lt;--- don't need this string
  </code></pre>
  
  <p>Perl regex I'm using return all four strings above when I only need the first string listed above. How do I filter out the last three strings and only get the first string?</p>