title: windows batch file rename
body: <p>I have some file such as <code>AAA_a001.jpg</code>, <code>BBB_a002.jpg</code>, <code>CCC_a003.jpg</code> in Windows 7
  and I'm trying to use batch to rename these file to <code>a001_AAA.jpg</code>, <code>a002_BBB.jpg</code>, <code>a003_CCC.jpg</code>.</p>
  
  <p>Just to swap the content between <code>_</code>.</p>
  
  <p>I have been searching for a while, but still don't know how to do this.
  Can anyone help? 
  Thanks.</p>