"I always find it amusing when I write something that spends a bunch of work making sure everything is freed before it exits."

Yeah, just exit! That's the kind of cool thing about these small, short lived Unix programs like grep and cat - chew memory (stack or heap, up to you!) and bail out - let the OS clean it up. It is essentially the same argument as "prefer large mallocs to small" - the process itself is a 'large malloc'.