brew/share/doc/homebrew/External-Commands.md

External Commands

Homebrew, like Git, supports external commands. This lets you create new commands that can be run like:

$ brew mycommand --option1 --option3 formula

without modifying Homebrew's internals.

COMMAND TYPES

External commands come in two flavors: Ruby commands and shell scripts.

In both cases, the command file should be chmod +x (executable) and live somewhere in $PATH.

Internally, Homebrew finds commands with which(1).

RUBY COMMANDS

An external command extcmd implemented as a Ruby command should be named brew-extcmd.rb. The command is executed by doing a require on the full pathname. As the command is required, it has full access to the Homebrew "environment", i.e. all global variables and modules that any internal command has access to.

The command may Kernel.exit with a status code if it needs to; if it doesn't explicitly exit then Homebrew will return 0.

SHELL SCRIPTS

A shell script for an command named extcmd should be named brew-extcmd. This file will be run via exec with some Homebrew variables set as environmental variables, and passed any additional command-line arguments.

Variable	Description
HOMEBREW_CACHE	Where Homebrew caches downloaded tarballs to, typically ~/Library/Caches/Homebrew.
HOMEBREW_CELLAR	The location of the Homebrew Cellar, where software is staged, by default /usr/local/Cellar.
HOMEBREW_LIBRARY_PATH	The directory containing Homebrew’s own application code.
HOMEBREW_PREFIX	Where Homebrew installs software to, by default /usr/local.
HOMEBREW_REPOSITORY	If installed from a Git clone, the repo directory (i.e., where Homebrew’s .git directory lives).

Note that the script itself can use any suitable shebang (#!) line, so an external “shell script” can be written for sh, bash, Ruby, or anything else.

USER-SUBMITTED COMMANDS

These commands have been contributed by Homebrew users but are not included in the main Homebrew repository, nor are they installed by the installer script. You can install them manually, as outlined above.

NOTE: They are largely untested, and as always, be careful about running untested code on your machine.

brew-cask

Install .app and other "Drag to install" packages from Homebrew.

https://github.com/caskroom/homebrew-cask

Install using:

$ brew tap caskroom/cask $ brew install brew-cask

brew-desc

Get short descriptions for Homebrew formulae or search formulae by description: https://github.com/telemachus/brew-desc

You can install manually or using brew tap:

$ brew install telemachus/desc/brew-desc

brew-gem and brew-pip

Install any gem pip package into a self-contained Homebrew cellar location

https://github.com/josh/brew-gem, https://github.com/josh/brew-pip

Note: These can also be installed with brew install brew-gem and brew install brew-pip

brew-growl

Get Growl notifications for Homebrew https://github.com/secondplanet/brew-growl

brew-more

Scrapes a formula's homepage to get more information: https://gist.github.com/475200

brew-services

Simple support to start formulae using launchctl, has out of the box support for any formula which defines startup_plist (e.g. mysql, postgres, redis u.v.m.): https://gist.github.com/766293

SEE ALSO

Homebrew Wiki: http://wiki.github.com/Homebrew/homebrew/

brew(1), which(1), grep(1), ronn(1)