I just got a couple USB Erupters and I am mining with them just fine. I would like to know if there is a command line argument I can use to disable my GPU from mining with BFGMiner.

using bfgminer -S all starts up both my USB Erupters and my GPU (shown as OCL 0). Then I have to go into GPU options and disable it.

How can I disable OCL 0 via command line when starting BFG Miner?