Hi Venkat,
I created a custom script (which I cannot find now or I would post it) from a Linux server with a lot of attached storage that basically ssh'd (shared keys) to the BigIP, ran the commands to create a .ucs, downloaded the .ucs, verified the ucs size (or you could create md5 to validate), removed the .ucs from the BigIP. The script also only kept the latest 5 backups of each device.
The best bet for you since you are not that familiar with scripting is to use google and pick a language... say Korn Shell (ksh) and then google for each step.
If you run into trouble post you progress here and we can help you through it.
Regards,
Seth Cooper