Mac, over at Quantum Donuts, put up a little video on YouTube as a how-to for writers. The terminology is a little more broken out than I usually use–I tend to just use either "stab" or "slash." (And "slice" is an alternative term to "slash.")
The first is a thrusting, or pushing motion, and the second more a waving action that eventually draws the knife sideways or backwards in a pull. A stab is usually–not always–like a punch or a hammer, with the arm extending. A slash tends to be like a slap. (One can stab on a drawing motion, of course, if one's hand is behind an opponent.)
Basically, that's all you do with any kind of muscular activity, push, pull, or combinations thereof.
Mac's divisions offer more detail, and it's a most useful bit of business if you are a writer and you don't know from knives.
Have a look: