On Gulp!
First, setting up the Gulp on mac os: type: sudo npm install gulp -g with the output showing : npm WARN deprecated gulp-util@3.0.8: gulp-util is deprecated - replace it, following the guidelines at https://medium.com/gulpjs/gulp-util-ca3b1f9f9ac5 npm WARN deprecated graceful-fs@3.0.11: please upgrade to graceful-fs 4 for compatibility with current and future versions of Node.js npm WARN deprecated minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue npm WARN deprecated minimatch@0.2.14: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue npm WARN deprecated graceful-fs@1.2.3: please upgrade to graceful-fs 4 for compatibility with current and future versions of Node.js /usr/local/bin/gulp -> /usr/local/lib/node_modules/gulp/bin/gulp.js + gulp@3.9.1 added 253 packages from 162 contributors in 52.885s gulp installed successfully! Gulp-sass: A tool to convert sass to css: 1. By typing: $ npm install gulp-sass --save-dev