Gulp for designers - Getting started with Gulp.js : http://insidethe.agency/blog/gulp-for-designers-getting-started-with-gulp-js

gulpfile.js

var gulp = require('gulp'),
    sass = require('gulp-sass'),
    minifyCSS = require('gulp-minify-css'),
    rename = require('gulp-rename');
    
    
gulp.task('sass-to-css-please', function() {

    return gulp.src('./scss/site.scss')
        .pipe(sass()) //Concatinate our Sass files into CSS
        .pipe(minifyCSS()) //Minify the CSS file that is output
        .pipe(rename('styles.min.css')) //Rename this CSS file
        .pipe(gulp.dest('./css/')); //Put this CSS in our CSS folder

});

package.json

{
    "name": "NewGulpProject",
    "description": "An example of how you can get started with Gulp.js",
    "version": "0.0.0",
    "author": "@alistairtweedie",
    "devDependencies": {
        "gulp": "3.9.0",
        "gulp-minify-css": "1.2.0",
        "gulp-rename": "1.2.2",
        "gulp-sass": "2.0.4"
    }
}

terminal.bash

$npm install gulp -g

$npm install gulp —save-dev

$ npm install gulp-sass gulp-minify-css gulp-rename —save-dev

$ gulp sass-to-css-please