It's one of those things that you don't usually need to think about, so you don't. Not too long ago I hit this same realization with pipes because my "grep ...

It's one of those things that you don't usually need to think about, so you don't. Not too long ago I hit this same realization with pipes because my "grep ... file | sed > file" (or something of that nature) was racey. I took the time to think about it and realized "oh I guess that's how pipes would _have_ to be implemented".