Hcitool
$ hcitool dev ## to see if the Device was detected
$ hcitool scan ## to see if the Device is able to do anything, got an error: Device is not available: No such device
# hciconfig hci0 up ## to power on the device, got an error: Can't init device hci0: Device or resource busy (16)
# hciconfig hci0 piscan Can't set scan mode on hci0: Network is down (100)
# hciconfig hci0 reset Can't init device hci0: Device or resource busy (16)