gulpfile.js

// Assigning modules to local variables
var gulp = require('gulp');
var less = require('gulp-less');
var header = require('gulp-header');
var cleanCSS = require('gulp-clean-css');
var rename = require("gulp-rename");
var pkg = require('./package.json');

// Set the banner content
var banner = ['/*!\n',
    ' * Start Bootstrap - Official Website (<%= pkg.homepage %>)\n',
    ' * Copyright 2013-' + (new Date()).getFullYear(), ' <%= pkg.author %>\n',
    ' * Licensed under <%= pkg.license.type %> (<%= pkg.license.url %>)\n',
    ' */\n',
    ''
].join('');

// Less task to compile the less files and add the banner
gulp.task('less', function() {
    return gulp.src('assets/less/startbootstrap.less')
        .pipe(less())
        .pipe(header(banner, { pkg: pkg }))
        .pipe(gulp.dest('assets/css'))
});

// Minify CSS
gulp.task('minify-css', function() {
    return gulp.src('assets/css/startbootstrap.css')
        .pipe(cleanCSS({ compatibility: 'ie8' }))
        .pipe(rename({ suffix: '.min' }))
        .pipe(gulp.dest('assets/css'))
});

// Watch Task that compiles LESS and minifies output CSS
gulp.task('dev', ['less' , 'minify-css'], function() {
    gulp.watch('assets/less/*.less', ['less']);
    gulp.watch('assets/css/*.css', ['minify-css']);
});