gulpfile for codeofcliber blog

gulpfile.js

var gulp = require('gulp');
var shell = require('gulp-shell');

var htmlmin = require('gulp-htmlmin');
gulp.task('htmlmin', function() {
    return gulp.src('./_site/**/*.html')
        .pipe(htmlmin({
            collapseWhitespace: true,
            removeComments: true,
            conservativeCollapse: true,
            collapseBooleanAttributes: true,
            removeRedundantAttributes: true,
            removeEmptyAttributes: true,
            removeEmptyElements: false,
            lint: false,
            minifyJS: true,
            minifyCSS: true,
        }))
        .pipe(gulp.dest('./_site/'));
});

var imagemin = require('gulp-imagemin');
gulp.task('imagemin', function () {
    return gulp.src('./_site/images/*.png')
        .pipe(imagemin([imagemin.optipng({optimizationLevel: 5})]))
        .pipe(gulp.dest('./_site/images'));
});

var cleanCss = require('gulp-clean-css');
var autoprefixer = require('gulp-autoprefixer');
gulp.task('build-css', function() {
    return gulp.src('_site/css/**/*.css')
        .pipe(cleanCss({compatibility: 'ie8'}))
        .pipe(autoprefixer({
            browsers: ['> 1%'],
            cascade: false
        }))
        .pipe(gulp.dest('./_site/css'));
});

var jsValidate = require('gulp-jsvalidate');
var uglify = require('gulp-uglify');
gulp.task('build-js', function() {
    return gulp.src('./_site/js/**/*.js')
        .pipe(jsValidate())
        .pipe(uglify())
        .pipe(gulp.dest('./_site/js/'));
});

gulp.task('copy_bower_components', function() {
    gulp.src([
        'bower_components/bootstrap/dist/css/bootstrap.min.css',
        'bower_components/bootstrap/dist/css/bootstrap-theme.min.css',
        'bower_components/fontawesome/css/font-awesome.min.css',
        'bower_components/normalize.css/normalize.css'
        ]).pipe(gulp.dest('./_site/vendor/css/'));
    gulp.src([
        'bower_components/bootstrap/dist/fonts/*',
        'bower_components/fontawesome/fonts/*',
        ]).pipe(gulp.dest('./_site/vendor/fonts/'));
    gulp.src([
        'bower_components/bootstrap/dist/js/bootstrap.min.js',
        'bower_components/jquery/dist/jquery.min.js',
        ]).pipe(gulp.dest('./_site/vendor/js/'));
    gulp.src([
        'bower_components/modernizr/modernizr.js',
        ]).pipe(uglify())
        .pipe(gulp.dest('./_site/vendor/js/'));
});

gulp.task('jekyll', shell.task(['jekyll build']));

gulp.task('build', ['jekyll'], function() {
    gulp.run('copy_bower_components');
    gulp.run('build-css');
    gulp.run('htmlmin');
    gulp.run('imagemin');
});

// check tasks
var bootlint = require('gulp-bootlint');
var html5Lint = require('gulp-html5-lint');
var htmlhint = require("gulp-htmlhint");
gulp.task('check-html', function() {
    return gulp.src('./_site/**/*.html')
        .pipe(html5Lint())
        .pipe(htmlhint())
        .pipe(bootlint());
});

var scsslint = require('gulp-scss-lint');
gulp.task('check-scss', function() {
    gulp.src([ './_sass/**/*.scss' ])
        .pipe(scsslint())
});

gulp.task('check', [ 'check-html', 'check-scss' ], function() {});

// serve task
gulp.task('jekyll-watch', shell.task(['jekyll build --watch --incremental']));

var browserSync = require('browser-sync').create();
gulp.task('webserver', function () {
    browserSync.init({
        port: 4000,
        open: true,
        reloadThrottle: 500,
        reloadDebounce: 500,
        server: {
            baseDir: '_site/'
        }
    });
    setTimeout(function () {
        gulp.watch('_site/**/*.*').on('change', browserSync.reload);
    }, 5000);
})

gulp.task('serve', ['jekyll-watch', 'copy_bower_components', 'webserver'], function () {});

// default task
gulp.task('default', [ 'build' ], function() {});

package.json

{
  "name": "hal-blog",
  "version": "1.0.0",
  "description": "My blog based on Jekyll",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "repository": {
    "type": "git",
    "url": "git@bitbucket.org:halex2005/hal-blog.git"
  },
  "keywords": [
    "jekyll",
    "blog"
  ],
  "author": "halex2005",
  "license": "BSD-2-Clause",
  "devDependencies": {
    "browser-sync": "^2.18.8",
    "gulp-autoprefixer": "^3.1.1",
    "gulp-bootlint": "^0.8.1",
    "gulp-clean-css": "^3.0.0",
    "gulp-html5-lint": "^1.1.0",
    "gulp-htmlhint": "^0.3.1",
    "gulp-htmlmin": "^3.0.0",
    "gulp-imagemin": "^3.2.0",
    "gulp-jsvalidate": "^3.0.0",
    "gulp-scss-lint": "^0.4.0",
    "gulp-shell": "^0.6.3",
    "gulp-uglify": "^2.1.2"
  }
}

You can see explanation of this gist on http://codeofclimber.ru/2015/use-gulp-to-automate-building-of-jekyll-based-site/