# Homebrew

1. [TL;DR](#tldr)
1. [Downgrade an application to a non-managed version](#downgrade-an-application-to-a-non-managed-version)
   1. [The easy way](#the-easy-way)
   1. [The hard way](#the-hard-way)
1. [Download packages preemptively](#download-packages-preemptively)
1. [Gotchas](#gotchas)
1. [Further readings](#further-readings)
1. [Sources](#sources)

## TL;DR

<details>
  <summary>Installation</summary>

```sh
# Install.
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

# Uninstall.
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/uninstall.sh)"
```

</details>
<details>
  <summary>Configuration</summary>

```sh
# Require SHA check for casks.
# Change cask installation dir to the Application folder in the user's HOME.
export HOMEBREW_CASK_OPTS="--require-sha --appdir $HOME/Applications"

# Print install times for each formula at the end of the run.
export HOMEBREW_DISPLAY_INSTALL_TIMES=1

# Do not automatically update before running some commands.
export HOMEBREW_NO_AUTO_UPDATE=1

# Do not print HOMEBREW_INSTALL_BADGE on a successful build.
export HOMEBREW_NO_EMOJI=1

# Do not use the GitHub API.
# Avoid searches or fetching relevant issues after a failed install.
export HOMEBREW_NO_GITHUB_API=1

# Forbid redirects from secure HTTPS to insecure HTTP.
export HOMEBREW_NO_INSECURE_REDIRECT=1

# Only list updates to installed software.
export HOMEBREW_UPDATE_REPORT_ONLY_INSTALLED=1

# Pass the -A option when calling sudo.
export SUDO_ASKPASS=1
```

</details>
<details>
  <summary>Usage</summary>

```sh
# Search for formulae.
brew search 'parallel'
brew search --cask 'gpg'

# Install something.
brew install 'gettext'
brew install --cask 'spotify'

# Get formulae's dependencies.
brew deps
brew deps --installed 'azure-cli'
brew deps --tree

# Get information on formulae.
brew info 'sponge'

# List all files installed by formulae.
brew ls -v 'coreutils'
brew ls -v --cask 'firefox'

# Prevent formulae from upgrading.
brew pin 'gnupg2'

# Uninstall something.
brew uninstall --zap 'keybase'

# (Re)create links for applications.
brew link 'kubernetes-cli'

# Show outdated casks.
brew outdated --cask --greedy

# Add taps.
# Only one at a time.
brew tap 'homebrew/services'

# Manage services.
# Requires the 'homebrew/services' tap.
brew services start 'openssl-osx-ca'

# Bring an installation up to speed from a Brewfile.
brew bundle
brew bundle --global
brew bundle --no-lock install --file "$HOME/Brewfile"

# Check what changes from a Brewfile.
brew bundle check
brew bundle … check --file "$HOME/Brewfile"

# Check what items not listed in a Brewfile would be removed.
brew bundle cleanup
brew bundle … cleanup --file "$HOME/Brewfile"

# Remove items not listed in a Brewfile.
brew bundle … --cleanup --zap

# Dump all installed casks/formulae/images/taps into a Brewfile.
brew bundle dump
```

</details>

## Downgrade an application to a non-managed version

### The easy way

```sh
brew unlink kubernetes-helm
brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/ed9dcb2cb455a816f744c3ad4ab5c18a0d335763/Formula/kubernetes-helm.rb
brew switch kubernetes-helm 2.13.0
```

### The hard way

[source](https://stackoverflow.com/questions/3987683/homebrew-install-specific-version-of-formula)
[alternative source](https://www.fernandomc.com/posts/brew-install-legacy-hugo-site-generator/)

```sh
formula_name='kubernetes-helm'
formula_version='2.13.1'

cd $(brew --repository)/Library/Tapshomebrew/homebrew-core
git log master -S${formula_version} -- Formula/${formula_name}.rb
commit_id='<something>'  # insert commit id

git checkout -b ${formula_name}-${formula_version} ${commit_id}
HOMEBREW_NO_AUTO_UPDATE=1 brew install ${formula_name}
# pin application if needed

git checkout master
git branch -d ${formula_name}-${formula_version}
```

## Download packages preemptively

Sometimes the file will continuously fail to download for some reason (like a badly configured antivirus software that keeps cutting out your download).

You can download the installation file yourself in steps and try the installation again:

```sh
$ brew install --cask 'docker'
…
==> Downloading https://desktop.docker.com/mac/main/amd64/131620/Docker.dmg
######################################################   36.6%curl: (18) Transferred a partial file

$ brew --cache 'homebrew/cask/docker'
/Users/username/Library/Caches/Homebrew/downloads/508b…95f1--Docker.dmg

$ curl -L -C - -o "$(brew --cache 'homebrew/cask/docker')" \
    'https://desktop.docker.com/mac/main/amd64/131620/Docker.dmg'
** Resuming transfer from byte position 1282048
…
curl: (18) Transferred a partial file

$ curl -L -C - -o "$(brew --cache 'homebrew/cask/docker')" \
    'https://desktop.docker.com/mac/main/amd64/131620/Docker.dmg'
** Resuming transfer from byte position 242762028
…

$ brew install --cask 'docker'
…
==> Downloading https://desktop.docker.com/mac/main/amd64/131620/Docker.dmg
Already downloaded: /Users/username/Library/Caches/Homebrew/downloads/508b…95f1--Docker.dmg
==> Installing Cask docker
…
docker was successfully installed!
```

See also [How to manually download brew package for installation?].

## Gotchas

- `moreutils` installs its own old version of `parallel`, which conflicts with the `parallel` formulae; install the standalone `gettext`, `parallel` and `sponge` to have their recent version

## Further readings

- [manpage]
- Homebrew [bundle]
- [Mas]
- [Whalebrew]

## Sources

- [How to stop homebrew from upgrading itself on every run]
- [macOS migrations with Brewfile]
- [How to manually download brew package for installation?]

<!--
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<!-- In-article sections -->
<!-- Knowledge base -->
[mas]: mas.md
[whalebrew]: whalebrew.md

<!-- Files -->
<!-- Upstream -->
[bundle]: https://github.com/Homebrew/homebrew-bundle
[manpage]: https://docs.brew.sh/Manpage

<!-- Others -->
[how to manually download brew package for installation?]: https://stackoverflow.com/questions/53551665/how-to-manually-download-brew-package-for-installation#53579448
[how to stop homebrew from upgrading itself on every run]: https://superuser.com/questions/1209053/how-do-i-tell-homebrew-to-stop-running-brew-update-every-time-i-want-to-install/1209068#1209068
[macos migrations with brewfile]: https://openfolder.sh/macos-migrations-with-brewfile