These formulae duplicate software provided by OS X, though may provide more recent or bugfix versions.
brew install homebrew/dupes/<formula>
Or brew tap homebrew/dupes
and then brew install <formula>
.
Or install via URL (which will not receive updates):
brew install https://raw.githubusercontent.com/Homebrew/homebrew-dupes/master/<formula>.rb
brew help
, man brew
or check Homebrew's documentation.