title: Unix sort of version numbers
body: <p>I have a list of version numbers, let's say for instance that they are in a file versions.txt</p>
  
  <pre><code>1.2.100.4
  1.2.3.4
  10.1.2.3
  9.1.2.3
  </code></pre>
  
  <p>I wish to sort them so that they are sorted by version.  i.e:</p>
  
  <pre><code>1.2.3.4
  1.2.100.4
  9.1.2.3    
  10.1.2.3
  </code></pre>
  
  <p>I have tried using various sort commands using the "k" parameters, but do not really understand it well enough to pull it off.  Any help would be appreciated.    </p>