A couple of tips for you, Prashant. This question does not demonstrate that you've done anything to help yourself. It does not describe what you've tried or where you are stuck. You'll get more help with potentially more actionable advice when you show that you've put some effort into the problem and you get more specific about exactly what you need.
Also, it seems that you've already asked this question once. This wastes the time of the community members, so going forward, limit yourself to one post on the same topic.
With all of that said, writing a script to export content should be straightforward if you are a coder. My advice is to choose your favorite programming language and then grab a CMIS client that works with that language and write the export yourself.
