GenerateBrewFile.sh

GenerateBrewFile.sh is a single-file Bash utility that builds a comprehensive Brewfile for your macOS machine. It combines the output of brew bundle dump with metadata about your Mac App Store purchases and locally installed .app bundles so that you have a complete, human-readable inventory of the software on your Mac.

Features

• Dumps all installed Homebrew formulae, casks, and taps using brew bundle dump.
• Optionally includes inline descriptions for formulae/casks when brew bundle dump --describe is supported.
• Adds a Mac App Store section (via the mas CLI) showing app names and IDs.
• Scans /Applications and ~/Applications for manually installed .app bundles and suggests matching casks where available.
• Notes any remaining apps that do not have an obvious cask, helping you track manual install steps.
• Works with the stock macOS Bash 3.2 runtime (no mapfile, uses POSIX-friendly constructs).

Prerequisites

Requirement	Purpose
macOS	The script depends on Homebrew and the macOS application bundle layout.
Homebrew	Provides the brew command used to dump your environment. If brew is missing the script attempts a non-interactive installation and configures the current shell session to use it.
mas CLI (optional)	Enables the Mac App Store section; without it the script records that MAS apps were skipped. When mas is missing the script installs it with Homebrew before proceeding.

Installation

Homebrew (Homebrew/homebrew-core)

GenerateBrewFile.sh is published in the main Homebrew tap starting with version 0.1.1. Install or upgrade it like any other core formula (release notes live on the v0.1.1 GitHub tag):

brew install generate-brewfile
# or
brew upgrade generate-brewfile

The formula bundles the GenerateBrewFile.sh script as the generate-brewfile CLI. It includes an automated brew test that exercises the --help and --version flags to keep parity with the upstream release process.

Installing HEAD builds

If you would like to track the latest commits between tagged releases you can use Homebrew's --HEAD flag:

brew install --HEAD generate-brewfile

Homebrew will clone the Git repository directly and build the CLI from the current main branch.

Note: Homebrew/homebrew-core accepts projects maintained by individuals. The formula points to the canonical repository under the timbroder account—no GitHub organization is required as long as the tagged release and checksum remain stable.

Manual installation

Clone the repository (or copy the script) and make it executable:

git clone https://github.com/timbroder/GenerateBrewFile.sh.git
cd GenerateBrewFile.sh
chmod +x GenerateBrewFile.sh

You can now run the script directly or move it somewhere on your $PATH (for example ~/bin).

Usage

From the repository root (or wherever the script lives), run:

./GenerateBrewFile.sh

By default this writes ~/Brewfile, includes descriptions when supported, and prints progress messages. You can override the output location directly from the command line:

./GenerateBrewFile.sh --brewfile /path/to/custom.Brewfile

To confirm which release is installed, run:

./GenerateBrewFile.sh --version

The script will then:

0. Ensure that both brew and the mas CLI are available, installing them automatically when necessary.
1. Require that brew exists, then run brew bundle dump --force --file "$BREWFILE" --describe.
2. If the mas CLI is installed and logged in, append your Mac App Store apps (mas "Display Name", id: 123456789).
3. Scan /Applications and ~/Applications for .app bundles that do not already appear in your MAS list, skip obvious Apple system apps, and try to match each bundle to a Homebrew cask token.
4. Record suggested cask names (e.g., # cask "google-chrome" # Google Chrome -> google-chrome).
5. List any remaining .app bundles that could not be mapped to a cask so you can document manual installation steps.
6. Finish with a reminder to validate using brew bundle check.

Environment variables

Variable	Default	Description
BREWFILE	$HOME/Brewfile	Path to write the generated Brewfile. Overridden by --brewfile when provided.
DESCRIBE	1	When set to 1 (default) the script adds --describe so formulae/casks include the Homebrew description text. Set to 0 to omit descriptions.
QUIET	0	Set to 1 to suppress log output (only errors will print).

You can combine these for different scenarios:

# Generate into the current directory without descriptions
BREWFILE="$(pwd)/Brewfile" DESCRIBE=0 ./GenerateBrewFile.sh

# Run silently and output to a custom path
QUIET=1 ./GenerateBrewFile.sh --brewfile "$HOME/Documents/work-mac.Brewfile"

Types of applications captured

GenerateBrewFile.sh inventories multiple categories of software:

• Homebrew formulae – Core packages installed via brew install.
• Homebrew casks – GUI apps, fonts, and other binary artifacts installed via brew install --cask.
• Homebrew taps – Additional tap repositories required by the above packages.
• Mac App Store apps – Applications associated with your Apple ID, collected with the mas CLI.
• Manually installed .app bundles – Applications living in /Applications or ~/Applications that are not otherwise tracked; the script suggests casks or flags them for manual follow-up.

Example output excerpt

# ------------------------------
# Mac App Store apps (via mas)
# ------------------------------
mas "Xcode", id: 497799835
mas "Things 3", id: 904280696

# ------------------------------
# Suggestions for manually installed apps
# ------------------------------
# Likely available as casks (unmanaged right now). Consider adding lines like:
#   cask "google-chrome"   # Google Chrome -> google-chrome
#   cask "spotify"         # Spotify -> spotify
#
# Remaining apps that don't have an obvious cask:
#   OmniGraffle

Validation

After generating your Brewfile you can confirm that Homebrew can satisfy it:

brew bundle check --file="/path/to/Brewfile"

Resolve any missing dependencies, then commit the Brewfile to source control or store it alongside your personal backups.

Troubleshooting

• Error: 'brew' is not installed or not on PATH. – Install Homebrew from brew.sh and ensure brew is available in your shell.
• mas section is missing. – Install mas (brew install mas) and log in (mas account) before running the script.
• Applications missing from suggestions. – Some bundles have unconventional names. Re-run the script periodically to refresh suggestions, or manually add the relevant cask or notes to your Brewfile.

Contributing

Issues and pull requests are welcome! Please open an issue describing the improvement you have in mind, or submit a PR directly.

License

This project is licensed under the terms of the MIT License.

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