title: How to run mongo shell using mongos command?
body: <p>I have two versions of <code>mongodb</code>, 2.4.3 and 2.6.0. I am able to start both the versions on different ports, but while running it using <b>./mongos</b> I get an error:</p>
  
  <pre><code>BadValue error: no args for --configdb
  </code></pre>
  
  <p>How can I resolve my issue?</p>