What happens if a batter accidentally, and as part of once action, hits the ball twice while playing shot? Will it be regarded as a normal shot, no runs or out?
If it makes a difference, the double hit happens before the ball touches the ground.
Accidentally hitting the ball twice as part of one motion has no effect on the game - runs are eligible to be scored as normal. There's nothing specific in the Laws of Cricket about this, other than to note that Law 34 Hit the ball twice refers specifically to the striker willfully striking the ball twice, and there is no mention in e.g. Law 20 Dead ball of the ball becoming dead if it is accidentally hit twice.