An easy, convenient way to automatically update Homebrew.

This script will run brew update in the background once every 24 hours (by default) until explicitly told to stop, utilising launchd.

brew upgrade and brew cleanup can also be handled automatically, but are optional flags.

Notifications are enabled by default on macOS Big Sur using a new, code-signed, universal AppleScript applet. On older versions of macOS, if you have terminal-notifier installed, you can also request desktop notifications when this command runs.

Just brew tap homebrew/autoupdate.

Now run brew autoupdate start [interval] [options] to enable autoupdate.

brew autoupdate start 43200 --upgrade --cleanup --immediate --sudo

This will upgrade all your casks and formulae every 12 hours and on every system boot.
If a sudo password is required for an upgrade, a GUI to enter your password will be displayed.
Also, it will clean up every old version and left-over files.

Casks that have built-in auto-updates enabled by default will not be upgraded.

Refer to the link below to find an in-depth description of the commands.

Homebrew Documentation autoupdate subcommand

Logs of the performed operations can be found at: ~/Library/Logs/com.github.domt4.homebrew-autoupdate

This command mostly exists to ensure Homebrew is updated regardless of whether you invoke brew or not, which is the primary difference from the autoupdate mechanism built into brew, the latter requiring a user to explicitly run any of brew install, brew tap or brew upgrade.

If you run brew commands regularly yourself, you may wish to consider using the built-in autoupdate mechanism, which can be instructed to autoupdate less often, or disabled entirely. If you wish to update every 24 hours using the built-in autoupdate mechanism set this in your environment:

export HOMEBREW_AUTO_UPDATE_SECS="86400"

or if you wish to disable the built-in autoupdate mechanism entirely:

export HOMEBREW_NO_AUTO_UPDATE="1"

Please note that Homebrew slightly frowns upon people disabling the built-in autoupdate mechanism.

• Complete broader testing and roll-out of new, experimental notification Support was added in 6365cc020 that doesn't require or use any external dependencies, using only an Applescript applet. Related Issue

This tap was created by DomT4 in April 2015 to address a personal desire for a background updater, before being moved to the Homebrew organisation in April 2021 to become an official part of the project after gaining somewhat widespread usage, something I'm both surprised by, but also very appreciative of people finding a small tool I wrote so useful & contributing their own ideas and time towards.

Code is under the BSD 2 Clause (NetBSD) license.