title: grep: group capturing
body: <p>I have following string:</p>
  
  <pre><code>{"_id":"scheme_version","_rev":"4-cad1842a7646b4497066e09c3788e724","scheme_version":1234}
  </code></pre>
  
  <p>and I need to get value of "scheme version", which is 1234 in this example.</p>
  
  <p>I have tried </p>
  
  <pre><code>grep -Eo "\"scheme_version\":(\w*)"
  </code></pre>
  
  <p>however it returns </p>
  
  <pre><code>"scheme_version":1234
  </code></pre>
  
  <p>How can I make it? I know I can add <strong>sed</strong> call, but I would prefer to do it with single grep.</p>