Can you answer these riddles?

What has an eye but cannot see

This thing all things devours; Birds, beasts, trees, flowers; Gnaws iron, bites steel; Grinds hard stones to meal; Slays king, and ruins town.

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

Voiceless it cries, Wingless flutters, Toothless bites, Mouth-less mutters. What is it?

Imagine you are in a dark room with no doors or windows. How do you get out?

What is always coming but never arrives?

Tear one off and scratch my head what was red is black instead. What am I?

There are three men in a boat with four cigarettes but no matches. How do they manage to smoke?