11 Feb 2021
Homebrew on Apple Silicon Macs
A mere five and a half weeks after I ordered it, my M1 MacBook Air has finally arrived! Phew. Here are my notes from porting my dotfiles and setting it up.
Homebrew
Installing Homebrew on M1 Macs is blessedly straightforward: you go to brew.sh and copy and paste the install command into your terminal.
However! On an M1 Mac, using the Homebrew installer puts your entire installation into /opt/homebrew instead of the previous usual /usr/local. You’ll want to check for that, and put it in your path ahead of /usr/local, if it exists. Here’s my snippet to make sure I always get the right brew on my path:
export BREW_PREFIX=$([[ "$(arch)" == "arm64" ]] && echo "/opt/homebrew" || echo "/usr/local")
[[ "$PATH" != "*$BREW_PREFIX/bin*" ]] && export PATH="$BREW_PREFIX/bin:$PATH"
Strap
If you use strap to set up new computers, keep in mind that it will skip the Homebrew installer and instead copy it directly into /usr/local. You’ll need to use the regular Homebrew install process above to get a copy installed into /opt/homebrew as well.
architectures
If you need bottles that only exist for Intel (like mas), you can create shell aliases to help you access that stuff more easily:
alias ibrew="arch -x86_64 /usr/local/bin/brew"
With that alias, you can use ibrew to manually force the Intel Homebrew installation, to install something you might not otherwise be able to install. The rest of the time, you can use regular brew to get native binaries that have been compiled for your machine.
brew bundle and mas
Speaking of things that you might not be able to install compiled for Apple Silicon, let’s talk about mas.
I use the brew bundle command (run automatically by Strap) to install a bunch of Homebrew formulas, casks, and even Mac App Store apps. However, the mas CLI tool used to manage apps from the Mac App Store hasn’t been ported to Apple Silicon yet.
For now, that means running brew bundle twice: first, comment out all the Mac App Store apps and run /opt/homebrew/bin/brew bundle. Then, comment out everything but the Mac App Store apps, and run arch -x86_64 /usr/local/bin/brew bundle to use the Intel version of mas to tell the OS to install the Mac App Store apps.
You’ll still get Apple Silicon native versions of the apps from the App Store, since Hombrew has no control over that, and is just asking the App Store to install an app by ID number.
share and enjoy
and with that, you’re all caught up! I’ve really been enjoying the improved keyboard, absurdly fast compilation speeds, and even more absurdly long battery life. For my uses, switching from Intel to Apple silicon feels a lot like the first time I got an SSD—my computer is visibly faster for almost everything I do. Running for 10 hours on a single battery charge is just ridiculous gravy on top.