I have implemented stuff like this. It is not even remotely a <1 hour project. Not if you want it to work reasonably well and not be broken all the time. It’s a

I have implemented stuff like this. It is not even remotely a <1 hour project. Not if you want it to work reasonably well and not be broken all the time. It’s a full workday for someone who already understands the problem. There are a number of cases you often want to handle: - Multiple files may change in quick succession, for example, if you hit “save all” in an editor. You might want to delay triggers to see if more events arrive. - You will sometimes see incomplete / corrupted versions of files, because you ran a command while another program was writing the file. The other program probably should atomically rewrite the file, but you’re stuck fixing the problem. The user doesn’t want to see errors from this and you generally want to rerun the command. - You need to execute commands in the correct order. - A command may change state from being queued&ready to having outdated inputs. If it’s just one command, sure, you could probably do it in an hour. But if there’s more than one command (usually the case!) then it gets far more complicated. Just looking at the last time I implemented something like this--it was watchman + about 500 lines of code figuring out which actions to run and when. And that’s not even with any parallel execution.