$ video -c white_balance_temperature=6500 $ video $ video -c reset $ video
BTW, no other subsystem of ours has this "reset" type thing. A few subsystems have persistance, but persistant modes are usually only in the software layer, not in the hardware layer. The normal idiom is when last-close happens in a driver, all modal-state is lost and restored to default, and when you use the driver again -- the new open gets you a raw configuration which is then changed via ioctl, before futher use.
