My Gulpfile

gulpfile.js

/* ==========================================================================
   Dependencies
   ========================================================================== */

var gulp = require('gulp'),
    clean = require('gulp-clean'),
    uglify = require('gulp-uglify'),
    imagemin = require('gulp-imagemin'),
    autoprefixer = require('gulp-autoprefixer'),
    concat = require('gulp-concat'),
    rename = require('gulp-rename'),
    sass = require('gulp-sass'),
    notify = require("gulp-notify"),
    cache = require('gulp-cache'),
    plumber = require('gulp-plumber'),
    browserSync = require('browser-sync'),
    lr = require('tiny-lr'),
    livereload = require('gulp-livereload'),
    server = lr();

/* ==========================================================================
   Sources - Set your folders here
   ========================================================================== */

var source = {
  // Javascript folder
  js_src: "./js",
  // Javascript Library folder
  js_libs: "./js/lib/"
};

/* ==========================================================================
   Sass watch task
   Watches and compiles sass files in sass directory, also applies autoprefier
   ========================================================================== */

gulp.task('sass', function(){
  return gulp.src('./sass/*.scss')
    .pipe(plumber({errorHandler: notify.onError("Ack. <%= error.message %>")}))
    .pipe(sass({
      outputStyle: 'compressed',
      noCache: true
    })
    .on('error', sass.logError))
    .pipe(autoprefixer('last 200 versions'))
    .pipe(gulp.dest('./'))
    .pipe(browserSync.reload({stream:true}));
});

/* ==========================================================================
   gulp scripts
   Concatenates and minifies javascript files excluding modernizr
   and IE6-8 specific selectivizr.js
   ========================================================================== */

// Your javascript vendor/library files to be concatenated and minified
gulp.task('scripts', ['cleanScripts'], function() {
  return gulp.src([source.js_libs+'/*.js', '!'+source.js_libs+'modernizr.js', '!'+source.js_libs+'selectivizr.js'])
    .pipe(concat("plugins.js"))
    .pipe(gulp.dest(source.js_src))
    .pipe(rename({suffix: '.min'}))
    .pipe(uglify())
    .pipe(gulp.dest(source.js_src))
    .pipe(notify({message: 'Scripts are done.'}));
});

// Clean plugins.min.js file
gulp.task('cleanScripts', function() {
  return gulp.src('./js/plugins.min.js', {read: false})
    .pipe(clean());
});

/* ==========================================================================
   gulp images
   Minifies images
   ========================================================================== */

gulp.task('images', function() {
  gulp.src('./images/**')
    .pipe(cache(imagemin({
      optimizationLevel: 4,
      progressive: true,
      interlaced: true
    })))
    .pipe(gulp.dest('./images/'))
    .pipe(notify({
      message: "Images are optimized."
  }));
});

/* ==========================================================================
   Fire up livereload server
   ========================================================================== */

gulp.task('reload', function () {
  gulp.src('./')
    .pipe(livereload(server));
});

// Static server
gulp.task('browser-sync', function() {
    browserSync.init(null, {
      server: {
        baseDir: "./"
      }
    });
});

/* ==========================================================================
   gulp watch
   Main gulp task to watch sass files and any file changes for livereload
   ========================================================================== */

gulp.task('watch', function () {

  // Listen on port 35729
  server.listen(35729, function (err) {
    if (err) {
      return console.log(err);
    }

    // Watch .scss files
    gulp.watch('sass/**/*.scss', ['sass']);

    // Watch all files for changes
    // We ignore the compiled css file so reload doesn't trigger twice
    gulp.watch(['./*', '!./*.css'], ['reload']);

  });
});

/* ==========================================================================
   default task
   ========================================================================== */

gulp.task('default', function(){
  gulp.start('watch', 'scripts', 'images');
});