gulpfile.js

var gulp = require('gulp'),
    sass = require('gulp-ruby-sass'),
    autoprefixer = require('gulp-autoprefixer'),
    minifyCss = require('gulp-minify-css'),
    rename = require('gulp-rename'),
    concat = require('gulp-concat'),
    uglify = require('gulp-uglify');
/* doesn't work
gulp.task('process-styles', function() {
      return gulp.src('main.scss')
        .pipe(sass({style: 'expanded' }))
         .pipe(gulp.dest('.'))
         console.log('I have to run gulp-ruby-sass');
    });
*/
// run with gulp process-styles
gulp.task('process-styles', function () { // sass
    return sass('src/css/main.scss') // or a folder source/
        .on('error', function (err) {
            console.error('Error!', err.message);
        })
        .pipe(autoprefixer({
            browsers: ['last 2 versions'],
            cascade: false
        }))
        .pipe(gulp.dest('dist/css/'))
        .pipe(rename({suffix: '.min'} ))
        .pipe(minifyCss({compatibility: 'ie8'}))
        .pipe(gulp.dest('dist/css/')); // or a folder result
});

// run with gulp process-scripts
gulp.task('process-scripts', function() {
      return gulp.src('src/js/*.js')
        .pipe(concat('main.js'))
        .pipe(gulp.dest('dist/js/'))
        .pipe(rename({suffix: '.min'}))
        .pipe(uglify())
        .pipe(gulp.dest('dist/js/'))
});

// run with gulp watch
gulp.task('watch', function() {
      gulp.watch('src/js/*.js', ['process-scripts'])
});



// gulp.task('callback', function () {
    // watch('src/css/**/*.css', function () {
        // gulp.src('css/**/*.css')
            // .pipe(watch('css/**/*.css'));
    // ));
// });


gulp.task('default', function() {
  // place code for your default task here
  console.log('Hello World! I have configured the gulpfile.js');
});