Short LESS/Sass Gruntfile

bootstrap.scss

@import "bower_components/bootstrap-sass/assets/stylesheets/bootstrap";

bower.json

{
  "name": "tmp",
  "version": "0.0.0",
  "authors": [
    "Stefan Baumgartner <sbaumg@gmail.com>"
  ],
  "license": "MIT",
  "ignore": [
    "**/.*",
    "node_modules",
    "bower_components",
    "test",
    "tests"
  ],
  "dependencies": {
    "bootstrap-sass": "~3.3.2",
    "bootstrap": "~3.3.2"
  }
}

Gruntfile.js

'use strict';

module.exports = function(grunt) {

	grunt.loadNpmTasks('grunt-contrib-sass');
	grunt.loadNpmTasks('grunt-contrib-less');
	require('time-grunt')(grunt);

	grunt.initConfig({
		sass: {
			dist: {
                options: {
                    style: 'compressed',
                    sourcemap: 'none'
                },
                files: {
                     'main-sass.css' : ['bootstrap.scss']
                }
            }
		},
		less: {
			dist: {
                options: {
                    compress: true
                },
                files: {
                     'main-less.css' : ['bower_components/bootstrap/less/bootstrap.less']
                }
            }
		}
	})

	grunt.registerTask('default', ['sass']);
};

package.json

{
  "name": "tmp",
  "version": "1.0.0",
  "description": "",
  "main": "Gruntfile.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "grunt": "^0.4.5",
    "grunt-contrib-less": "^1.0.0",
    "grunt-contrib-sass": "^0.9.2",
    "time-grunt": "^1.0.0"
  }
}