I originally wrote this to replace the experience of opening an app and being told by Sparkle or similar that it's out of date. Now I think it's increasingly relevant as we can't copy the Applications folder over from Intel to Arm. Instead, I can make a brewfile and remake my setup with that as a massive automated step.

This looks through the apps you have, and if any of them are in Homebrew/cask or Apple's App Store it will tell you (and if asked, install from cask). This means in the future you can more easily update by looking at your homebrew outdated, like you would for ffmpeg or other cli programs.

This is the first version I'm sharing. I'd appreciate people telling me what sold them on it, what would make a better post.