greg@greg-laptop:~/aokp$ out/host/linux-x86/bin/emulator -partition-size 256

emulator: ERROR: You did not specify a virtual device name, and the system
directory could not be found.

If you are an Android SDK user, please use '@<name>' or '-avd <name>'
to start a given virtual device (see -help-avd for details).

Otherwise, follow the instructions in -help-disk-images to start the emulator