Utilisation de cask puis de brew install

J'essaie d'installer gulp - qui semble nécessiter le premier cask :

17:14:34/mozaik-demo $brew install gulp
Error: No available formula for gulp
Searching formulae...
Searching taps...
Caskroom/cask/gulp

Installons le tonneau :

17:14:41/mozaik-demo $brew cask install gulp
==> Downloading https://github.com/sindresorhus/gulp-app/releases/download/0.1.0/gulp.app.zip
######################################################################## 100.0%
==> Symlinking App 'gulp.app' to '/Users/steve/Applications/gulp.app'
  gulp staged at '/opt/homebrew-cask/Caskroom/gulp/0.1.0' (830 files, 75M)

Mais quelle est l'étape suivante ? Voici ma tentative :

17:15:03/mozaik-demo $brew install gulp
Error: No available formula for gulp
Searching formulae...
Searching taps...
Caskroom/cask/gulp
17:15:09/mozaik-demo $which gulp