text: var purify = require('purify-css');
  require('shelljs/global');
  
  // purify style.css
  exec('jekyll build', function(code, stdout, stderr) {
  });
  
  var content = [
      '_site/index.html',
      '_site/404.html',
      '_site/blog/index.html',
      '_site/linux/index.html',
      '_site/donate/index.html',
      '_site/html/2017/01/31/3-steps-to-setup-website-with-Jalpc.html'
  ];
  
  var css = ['static/css/style.css'];
  
  var options = {
      output: 'static/css/style-purify.css'
  };
  
  purify(content, css, options);
  