I\'m familiarizing myself with the whole homebrew kit and the documentation is rather poor. What is a cask, Cellar and a tap?
Homebrew-Cask is an extension to Homebrew to install GUI applications such as Google Chrome or Atom. It started independently but its maintainers now work closely with Homebrew’s core team.
Homebrew calls its package definition files “formulae” (British plural for “formula”). Homebrew-Cask calls them “casks”. A cask, just like a formula, is a file written in a Ruby-based DSL that describes how to install something.
The Cellar is where Homebrew installs things. Its default path is /usr/local/Cellar
. It then add symlinks from standard locations to it.
For example, when you type brew install git
:
/usr/local/Cellar/git//
, with the git
binary in /usr/local/Cellar/git//bin/git
/usr/local/bin/git
to that binaryThis allows Homebrew to keep track of what’s installed by Homebrew versus software installed by other means.
A tap
is a source of formulae. The default is homebrew/core
but you can add more of them. The simplest way to create a formula for your own software is to create a GitHub repository called homebrew-
; put your formula file in it; then type brew tap
to add this new source of formulae to your Homebrew installation and so get access to all its formulae.
Some companies have internal Homebrew taps for their own utilities. There are a lot of public taps like atlassian/tap for Atlassian software, or ska-sa/tap for radio astronomy. Homebrew itself used to have additional taps like homebrew/science
but they deprecated them and imported the formulæ in homebrew/core
.