How to shut down Android emulator via command line

I am unable to stop the emulator from command prompt gracefully.

I am using Linux Ubuntu 10.04 version (64-bit) and Android SDK Version is 2.3.

I started emulator using its snapshot. Now my concern is to shut down the running instance of Emulator gracefully. I have tried with kill -9 (process Id for emulator running) which shut downs the emulator but next time it does not start as its snapshot got corrupted. Please help me to avoid forceful shutdown of the an emulator.

Any idea how to fix it?