brew Command Reference: Flags, Usage & CI Examples

brew is the Homebrew package manager for macOS and Linux.

brew installs command-line tools and (via casks) applications on macOS runners, where apt and yum are unavailable. It is the default way to add toolchain dependencies on GitHub-hosted macOS images.

Common flags and usage

install <formula...>: install command-line packages
install --cask <app>: install a GUI application
bundle --file=Brewfile: install everything in a Brewfile
list / info: list installed packages or show details
HOMEBREW_NO_AUTO_UPDATE=1: skip the slow auto-update
HOMEBREW_NO_INSTALL_CLEANUP=1: skip post-install cleanup

Example

shell

export HOMEBREW_NO_AUTO_UPDATE=1
brew install postgresql@16 jq
brew bundle --file=Brewfile

In CI

Set HOMEBREW_NO_AUTO_UPDATE=1 so brew does not spend a minute updating itself before every install. A checked-in Brewfile plus brew bundle makes macOS toolchain setup reproducible across runs.

Key takeaways

brew is the package manager for macOS CI runners.
HOMEBREW_NO_AUTO_UPDATE=1 avoids slow auto-updates per install.
brew bundle with a Brewfile makes setup reproducible.

Related guides

apk Command Reference: Flags, Usage & CI ExamplesReference for Alpine apk: add, --no-cache, --virtual, del, and a CI example that installs build dependencies… apt-get Command Reference: Flags, Usage & CI ExamplesReference for apt-get: update, install, -y, DEBIAN_FRONTEND, --no-install-recommends, and a CI example that i… dnf Command Reference: Flags, Usage & CI ExamplesReference for dnf: install, -y, --setopt=install_weak_deps, remove, clean all, and a CI example that installs…