title: Trying to remove duplicates words in a String using sed of MacOS
body: <p>I'm trying to remove duplicates words in a string using sed from MacOS using the following command:</p>
  <pre><code>sed -r 's/^([A-Za-z0-9_]+) \1$/\1/' &lt;&lt;&lt; 'The best of of The United Kingdom'
  </code></pre>
  <p>But it only returns</p>
  <pre><code>The best of of United Kingdom
  </code></pre>
  <p>What I'm missing? Could you guys give me hand? Please.</p>