title: Grep between two patterns in file
body: <p>Example</p>
  
  <pre><code>Date &amp; Time : 2016-01-23 02:00:00
  abc
  abc
  abc
  Date &amp; Time : 2016-01-24 03:00:00
  abc
  abc
  abc
  abc
  Date &amp; Time : 2016-01-25 05:00:00
  </code></pre>
  
  <p>I want to calculate the total number of abc between two patterns (say 2016-01-23 and 01-24) and then (say 2016-01-24 to 2016-01-26) .</p>