title: Subtracting two timestamps in bash script
body: <p>I have a file that contains a set of Timestamps in format of <code>H:M:S.MS</code>, I can read and print all of the saved Timestamps but when I do some arithmetic operation like Subtract (say <code>Timestamp2 - Timestamp1</code>) it doesn't give me the answer, I do not have experience work with bash script programming. </p>
  
  <p>Any suggestions, recommendations will be much appreciated.</p>
  
  <p>Here is the <a href="https://i.stack.imgur.com/Vomda.png" rel="noreferrer">screen shot</a> of my problem.</p>
  
  <p>Here is an example :</p>
  
  <pre><code>Start Time = 17:53:01.166721
  End Time = 17:53:01.369787
  </code></pre>
  
  <p>The expected result for <code>End Time - Start Time</code> is either <code>0:00:0.203066</code> or <code>0.203066</code>.</p>