This is not the knowledge that Shankara is speaking of when he distinguishes it from action. Human knowledge is an action alone, because it is produced by the motion of the mind and the senses. The knowledge propounded in the Advaita Vedanta is objectless knowledge, and it is never produced but realised. It is not the knowledge of something but the knowledge of the knower himself. It is Atma-Sakshatkara that Shankara means by knowledge when he says that action is the antithesis of knowledge.
Action is generally an effort towards the achievement of an end.
Man does not simply exist. He ever tries to become something else. He is never satisfied with simply existing. He wishes to change, to become. The impulse for action is ingrained in the very constitution of the individual.