Skip this step if you have node installed globally already.
Open your terminal and run npm install -g
You may need to still install a package globally if it is missing from your folder.
npm install -g <package>
npm link gulp
npm link gulp-autoprefixer
npm link gulp-concat
npm link gulp-gettext
npm link gulp-jshint
npm link gulp-plumber
npm link gulp-rename
npm link gulp-rtlcss
npm link gulp-sass
npm link gulp-sort
npm link gulp-sourcemaps
npm link gulp-uglify
npm link gulp-util
npm link gulp-wp-pot
npm link map-stream
npm link hoek
npm link include-media
npm link js-yaml
npm link jshint
npm link minimatch
npm link minimist
npm link randomatic
npm link sass-lint
npm link shelljs
npm link tough-cookie
npm link webpack
If you are having problems try set the permissions for the global node modules folder.
sudo chown -R root:YOUR_USERNAME /usr/local/lib/node_modules/
sudo chmod -R 775 /usr/local/lib/node_modules/