What Am I Riddles

Question: You are my brother, but I am not your brother. Who am I?

Question: A man shaves several times a day, yet he still has a beard.

Who is this man?

Question: The more you take, the more you leave behind.
What are they?

Question: If you have me, you want to share me. If you share me, you haven't got me. What am I?

Question: I have all of your knowledge but could fit in your hands.

What am I?