Important Considerations:
* Why are you bypassing the pump? This is crucial. If you're doing it for a temporary fix because the pump is failing, it's fine for a short drive to a repair shop. However, driving for extended periods without power steering is dangerous, especially at higher speeds or in tight maneuvers.
* Finding the right belt: You'll need to either find a shorter pre-made belt from an auto parts store (explain your situation clearly), or have a belt professionally cut and spliced to the correct length. Simply using a random shorter belt could cause belt slippage or damage to other components.
* Risk of damage: While bypassing the pump doesn't directly harm other parts, driving without power steering puts extra strain on the steering linkage.
In short, it's possible, but it's a temporary solution best used only for short distances to get your car to a mechanic. Replacing or repairing the power steering pump is the proper and safest long-term solution.