GFork

Press X or V to toggle run or crouch.

X will simulate a Shift keydown event, and V will simulate a Z keydown event.

If you press Shift or C while you are keeping run or crouch, you will NOT cancel your run or crouch. To avoid suprise, a info display is added to the left-down corner, showing whether you are running, whether you are crouching, and which key you are pressing to run or crouch.