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* doc: move language reference to docs.brew.sh

* doc: reference Cask Cookbook instead of language reference
26 contributors

Users who have contributed to this file

@vitorgalvao @reitermarkus @miccal @commitay @muescha @SMillerDev @vszakats @claui @iMonZ @zmwangx @waldyrious @tsparber

Note: Before taking the time to craft a new cask, make sure

Adding a Cask

Making a new Cask is easy. Follow the directions in Getting Set Up To Contribute to begin.

Examples

Here’s a Cask for shuttle as an example. Note the comment above url, which is needed when the url and homepage hostnames differ

cask "shuttle" do
  version "1.2.9"
  sha256 "0b80bf62922291da391098f979683e69cc7b65c4bdb986a431e3f1d9175fba20"

  url "https://github.com/fitztrev/shuttle/releases/download/v#{version}/Shuttle.zip",
      verified: "github.com/fitztrev/shuttle/"
  appcast "https://github.com/fitztrev/shuttle/releases.atom"
  name "Shuttle"
  desc "Simple shortcut menu"
  homepage "https://fitztrev.github.io/shuttle/"

  app "Shuttle.app"

  zap trash: "~/.shuttle.json"
end

And here is one for advancedcolors. Note that it has an unversioned download (the download url does not contain the version number, unlike the example above). It also suppresses the checksum with sha256 :no_check, which is necessary because the checksum will change on the same url when a new distribution is made available.

cask "advancedcolors" do
  version "1.0.0"
  sha256 :no_check

  url "https://advancedcolors.com/AdvancedColors.zip"
  name "Advanced Colors"
  desc "Lightning fast swatch tool for designers and developers"
  homepage "https://advancedcolors.com/"

  app "AdvancedColors.app"
end

Here is a last example for airdisplay, which uses a pkg installer to install the application instead of a stand-alone application bundle (.app). Note the uninstall pkgutil stanza, which is needed to uninstall all files which were installed using the installer.

You will also see how to adapt version to the download url. Use our custom version methods to do so, resorting to the standard Ruby String methods when they don’t suffice.

cask "airdisplay" do
  version "3.4.2"
  sha256 "272d14f33b3a4a16e5e0e1ebb2d519db4e0e3da17f95f77c91455b354bee7ee7"

  url "https://www.avatron.com/updates/software/airdisplay/ad#{version.no_dots}.zip"
  appcast "https://www.avatron.com/updates/software/airdisplay/appcast.xml"
  name "Air Display"
  desc "Utility for using a tablet as a second monitor"
  homepage "https://avatron.com/applications/air-display/"

  depends_on macos: ">= :mojave"

  pkg "Air Display Installer.pkg"

  uninstall pkgutil: [
    "com.avatron.pkg.AirDisplay",
    "com.avatron.pkg.AirDisplayHost2",
  ]
end

Generating a Token for the Cask

The Cask token is the mnemonic string people will use to interact with the Cask via brew install, etc. The name of the Cask file is simply the token with the extension .rb appended.

The easiest way to generate a token for a Cask is to run this command:

$ "$(brew --repository)/Library/Taps/homebrew/homebrew-cask/developer/bin/generate_cask_token" '/full/path/to/new/software.app'

If the software you wish to Cask is not installed, or does not have an associated App bundle, just give the full proper name of the software instead of a pathname:

$ "$(brew --repository)/Library/Taps/homebrew/homebrew-cask/developer/bin/generate_cask_token" 'Google Chrome'

If the generate_cask_token script does not work for you, see Cask Token Details.

The brew create --cask Command

Once you know the token, create your Cask with the handy-dandy brew create --cask command:

$ brew create --cask download-url --set-name my-new-cask

This will open $EDITOR with a template for your new Cask, to be stored in the file my-new-cask.rb. Running the create command above will get you a template that looks like this:

cask "my-new-cask" do
  version ""
  sha256 ""

  url "download-url"
  name ""
  desc ""
  homepage ""

  app ""
end

Cask Stanzas

Fill in the following stanzas for your Cask:

name value
version application version
sha256 SHA-256 checksum of the file downloaded from url, calculated by the command shasum -a 256 <file>. Can be suppressed by using the special value :no_check. (see sha256)
url URL to the .dmg/.zip/.tgz/.tbz2 file that contains the application.
A comment must be added if the hostnames in the url and homepage stanzas differ. Block syntax is available for URLs that change on every visit
name the full and proper name defined by the vendor, and any useful alternate names (see Name Stanza Details)
desc one-line description of the software (see Desc Stanza Details)
homepage application homepage; used for the brew home command
app relative path to an .app bundle that should be moved into the /Applications folder on installation (see App Stanza Details)

Other commonly-used stanzas are:

name value
appcast a URL providing an appcast feed to find updates for this Cask. (see Appcast Stanza Details)
pkg relative path to a .pkg file containing the distribution (see Pkg Stanza Details)
caveats a string or Ruby block providing the user with Cask-specific information at install time (see Caveats Stanza Details)
uninstall procedures to uninstall a Cask. Optional unless the pkg stanza is used. (see Uninstall Stanza Details)
zap additional procedures for a more complete uninstall, including configuration files and shared resources (see Zap Stanza Details)

Additional artifact stanzas you might need for special use-cases can be found here. Even more special-use stanzas are listed at Optional Stanzas.

Cask Token Details

If a token conflicts with an already-existing Cask, authors should manually make the new token unique by prepending the vendor name. Example: unison.rb and panic-unison.rb.

If possible, avoid creating tokens which differ only by the placement of hyphens.

To generate a token manually, or to learn about exceptions for unusual cases, see token_reference.md.

Archives With Subfolders

When a downloaded archive expands to a subfolder, the subfolder name must be included in the app value.

Example:

  1. Texmaker is downloaded to the file TexmakerMacosxLion.zip.
  2. TexmakerMacosxLion.zip unzips to a folder called TexmakerMacosxLion.
  3. The folder TexmakerMacosxLion contains the application texmaker.app.
  4. So, the app stanza should include the subfolder as a relative path:
app "TexmakerMacosxLion/texmaker.app"

Testing Your New Cask

Give it a shot with:

export HOMEBREW_NO_AUTO_UPDATE=1
brew install my-new-cask

Did it install? If something went wrong, edit your Cask with brew edit my-new-cask to fix it.

Test also if the uninstall works successfully:

brew uninstall my-new-cask

If everything looks good, you’ll also want to make sure your Cask passes audit with:

brew audit --new-cask my-new-cask

You should also check stylistic details with brew style:

brew style --fix my-new-cask

Keep in mind all of these checks will be made when you submit your PR, so by doing them in advance you’re saving everyone a lot of time and trouble.

If your application and Homebrew Cask do not work well together, feel free to file an issue after checking out open issues.

Finding a Home For Your Cask

See the Acceptable Casks documentation.

Submitting Your Changes

Hop into your Tap and check to make sure your new Cask is there:

$ cd "$(brew --repository)"/Library/Taps/homebrew/homebrew-cask
$ git status
# On branch master
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#       Casks/my-new-cask.rb

So far, so good. Now make a feature branch my-new-cask-branch that you’ll use in your pull request:

$ git checkout -b my-new-cask-branch
Switched to a new branch 'my-new-cask-branch'

Stage your Cask with:

$ git add Casks/my-new-cask.rb

You can view the changes that are to be committed with:

$ git diff --cached

Commit your changes with:

$ git commit -v

Commit Messages

For any git project, some good rules for commit messages are:

  • The first line is commit summary, 50 characters or less,
  • Followed by an empty line,
  • Followed by an explanation of the commit, wrapped to 72 characters.

See a note about git commit messages for more.

The first line of a commit message becomes the title of a pull request on GitHub, like the subject line of an email. Including the key info in the first line will help us respond faster to your pull.

For Cask commits in the Homebrew Cask project, we like to include the Application name, version number, and purpose of the commit in the first line.

Examples of good, clear commit summaries:

  • Add Transmission.app v1.0
  • Upgrade Transmission.app to v2.82
  • Fix checksum in Transmission.app Cask
  • Add CodeBox Latest

Examples of difficult, unclear commit summaries:

  • Upgrade to v2.82
  • Checksum was bad

Pushing

Push your changes from the branch my-new-cask-branch to your GitHub account:

$ git push {{my-github-username}} my-new-cask-branch

If you are using GitHub two-factor authentication and set your remote repository as HTTPS you will need to set up a personal access token and use that instead of your password. Further information here.

Filing a Pull Request on GitHub

a) suggestion from git push

The git push command prints a suggestion to create a pull request:

remote: Create a pull request for 'new-cask-cask' on GitHub by visiting:
remote:      https://github.com/{{my-github-username}}/homebrew-cask/pull/new/my-new-cask-branch

b) use suggestion at Github website

Now go to the homebrew-cask GitHub repository. GitHub will often show your my-new-cask-branch branch with a handy button to Compare & pull request.

c) manually create a pull request at Github website

Otherwise, click the New pull request button and choose to compare across forks. The base fork should be Homebrew/homebrew-cask @ master, and the head fork should be my-github-username/homebrew-cask @ my-new-cask-branch. You can also add any further comments to your pull request at this stage.

Congratulations!

You are done now, and your Cask should be pulled in or otherwise noticed in a while. If a maintainer suggests some changes, just make them on the my-new-cask-branch branch locally and push.

Cleaning up

After your Pull Request is submitted, you should get yourself back onto master, so that brew update will pull down new Casks properly:

cd "$(brew --repository)"/Library/Taps/homebrew/homebrew-cask
git checkout master

if you set the variable HOMEBREW_NO_AUTO_UPDATE then clean it up with:

unset HOMEBREW_NO_AUTO_UPDATE