title: How to identify date of 6 complete months ago
body: <p>I need to identify the date which is 6 complete months ago. For example:</p>
  
  <pre class="lang-none prettyprint-override"><code>Feb-27, 2012(Today) - It is Feb and we don't count incomplete month, false
  Feb-01, 2012 - Still Feb so don't count too, false
  Jan-01, 2011 - Completed, false
  Dec-01, 2011 - Completed, false
  Nov-01, 2011 - Completed, false
  Oct-01, 2011 - Completed, false
  Sep-01, 2011 - Completed, false
  Aug-01, 2011 - Completed, false
  Jul-01, 2011 - Already pass 6 complete months, true
  </code></pre>
  
  <p>It should work in whatever date in the future.</p>
  
  <p>I thought of current date minus 30*6=180 days, but it is not accurate. </p>
  
  <p>It needs to be accurate because, for example, if we identify Jul 2011 is valid then <em>we will housekeep all the data for that month</em>.</p>
  
  <p>Thanks.</p>