Sample Gulp Sass compile

gulpfile.js

// Compile Our Sass
gulp.task('sass', function() {
  browserSync.notify('<span style="color: grey">Running:</span> Sass compiling');
  return gulp.src(paths.sass)
    .pipe(sass({
      bundleExec: true,
      style: 'expanded',
      onError: browserSync.notify
    }))
    .pipe(prefix("last 2 versions", "> 1%"))
    .pipe(gulp.dest('_src/css'))
    .pipe(gulp.dest(paths.assets))
    .pipe(browserSync.reload({stream:true}));;
});

// Watch Files For Changes
gulp.task('watch', function() {
  gulp.watch(paths.scripts, ['lint', 'jekyll-rebuild']);
  gulp.watch(paths.sassFiles, ['sass']);
  gulp.watch(paths.imagesSrc, function() {
    runSequence(['images'], ['jekyll-dev'])
  });
  gulp.watch(paths.jekyll, ['jekyll-rebuild']);
});

//////////////////////////////
// BrowserSync Task
//////////////////////////////
gulp.task('browserSync', function () {
  browserSync.init([
    '_site/' + paths.assets +  '/**/*.css',
    '_site/' + paths.assets + '/**/*.js',
    '_site/**/*.html',
  ], {
    server: {
      baseDir: '_site'
    },
    host: "localhost"
  });
});