How do they shell walnuts

I saw at the store a bag of shelled walnuts. That got me thinking, how do they shell walnuts? Is there someone who stands there cracking open walnuts all day and dropping the contents out, or does a machine do it? And how might said machine work if that is the case?

It is done by machine. Here is a video of a smaller one.

I’m sure it is hand shelled in some countries or on smaller farms. A nasty, nasty business. The “nut” is covered in green skin. When it turns black and can stain your hands for days, then it’s ready to pick.

Naval bombardment?

This isn’t a problem - when they’re ripe, the green husks split and the nuts drop out fairly clean.