RANGERs are a light infantry force. We specialize in raids and fast movement. We train to kick in doors and shoot people. Jump out of planes and shoot people. Lie in a swamp for a couple days and then shoot people. We move behind enemy lines with no support under the theory that if you throw a bunch of highly trained, motivated, well armed, pissed off young men with no proper supervision at a problem and tell them to go fuck it up, you're going to see some results.
Army Special Forces (Green Berets) are an irregular warfare force. They specialize in sabotage, infiltration and having informants. Essentially they are a US Army Force with the same purview as the SEALs. When I was joining the military this job required a 9 year contract, that you be 21+ or receive a waiver and involved 2 1/2 years of training and you will see deployments before you finish this training. (but then again, Afghanistan is an amazing training ground and the Pushtun are kind enough to play red team for free)
Most SF guys have gone through every combat and survival school that i have, and then they've done Intel stuff relevant for their field as well. They fail any portion of the 2 1/2 years of training they're getting dumped. Then they'll wind up in either an infantry or MI position, a few RANGERs I know got dumped in SF selection but still had the beastliness we look for in the regiment.
So Rolf has question for thee about organisation of US military, has Rolf.
What are the primary differences between Army Special Forces and Army Rangers? asks Rolf, to the limited knowledge of U.S military structuring they seem to fill similar tasks, however mighty Rolf would appreciate some first-hand enlightenment on the subject, states Rolf.