You can run it on the command line, you say rough and you point at either a file or a directory. It's fast enough that basically as you save it, if there's problems that'll just appear in the terminal. The other thing that's interesting is you can do it as a pre-commit hook, which is nice. I think a lot of people seem to use it. And because it's fast, it just reruns, right? But it's very handy though that it's there.