Am I Dreaming?

How would I know whether I am in a dream or not? How can one know that for real. Is this blog i am creating right now actually exist?? How can one distinguish between wake up state and dream state. No I am not saying its from the matrix movie. Matrix was not a dream. It existed as a collective interaction between the minds of people. I recently read there is a kind of spectacles which you wear and go to sleep and it will partially wake you up when you are in a dream state. You cannot get out of a dream, but you know you are awake. Scary!