It makes a decent interview question tho', "explain the difference between cat file|./prog and ./prog <file". It doesn't even matter if they get it wrong, that they even know there is a difference is a very good sign.
I think most people wouldn't know the difference (I had no idea!) and the knowledge might fall into the realm of obscure trivia.
People who have come into SA work via being C programmers usually figure it out, they make the best SAs because they are mentally equipped to reason about a system from first principles.