What am I?

I am the ruler of shovels, I have a double, I am as thin as a knife, I have a wife. What am I?

related riddles

I am black, white, and read all over. What am I?

Like a river I flow, and you’re happy I do in vain. There is no escaping from my course, without causing pain. What am I?

I go in dry and come out wet, the longer I'm in, the stronger I get. What am I?