title: Change all file name and extension in directory in linux or windows
body: <p>I have thousands of file with file extensions like this</p>
  
  <pre><code>3_bedroom_villas_in_chennai.html__201308050010_
  3_bedroom_villas_in_chennai.html__201308080012_
  3_bedroom_villas_in_chennai.html__201308100012_
  3_bedroom_villas_in_chennai.html__201308110034_ and so on.....
  </code></pre>
  
  <p>inside a directory. I wanna change all these into the following</p>
  
  <pre><code>3_bedroom_villas_in_chennai__201308050010_.html
  3_bedroom_villas_in_chennai__201308080012_.html
  3_bedroom_villas_in_chennai__201308100012_.html
  3_bedroom_villas_in_chennai__201308110034_.html
  </code></pre>
  
  <p>When I tried doing it in windows using the following command</p>
  
  <pre><code>ren *.* *.html
  </code></pre>
  
  <p>I got the following</p>
  
  <pre><code>A duplicate file name exists, or the file
  cannot be found.
  A duplicate file name exists, or the file
  cannot be found.
  A duplicate file name exists, or the file
  cannot be found.
  A duplicate file name exists, or the file
  cannot be found. and so on...
  </code></pre>
  
  <p>Because I know that it will try to change everything into a single file name like</p>
  
  <pre><code>3_bedroom_villas_in_chennai.html and so on... 
  </code></pre>
  
  <p>any ways to do this either on windows or linux ??</p>