Following a conversation on the Brew forums, I’ve posted my shell script and launchd plist which can be used to keep
brew up to date:
The purpose is that when you go to update / install something with
brew it will go through the update process first, which can take awhile if you have not run it recently.
My script runs it every 2 days (which you can easily change) and it runs in the background, so you should never even notice it is running.
OTOH, If you have
terminal-notifier installed, it will use those to inform you of what it is doing, but even that can be disabled if you prefer.
Let me know if you have any questions or problems getting it to work.