title: Update variable used by Grunt Template
body: <p>I am using Grunt Templates, but wondering how I can update the variable which is used. Please check out the example below.</p>
  
  <pre><code>(function () {
      "use strict";
  
      module.exports = function(grunt) {
  
          grunt.initConfig({
  
              directory: 'deploy', // I want to be able to update this
  
              concat: {
                  options: {
                      separator: ';\n\n',
                      banner: '/*! Last edited: &lt;%= grunt.template.today("yyyy-mm-dd") %&gt; */\n /* DO NOT EDIT THIS FILE DIRECTLY */\n\n'
                  },
                  js_site: {
                      src: '&lt;%= directory %&gt;/assets/js/src/*.js',
                      dest: '&lt;%= directory %&gt;/assets/js/site.js',
                  },
                  js_vendor: {
                      src: '&lt;%= directory %&gt;/assets/js/vendor/*.js',
                      dest: '&lt;%= directory %&gt;/assets/js/vendor.js',
                  }
              },
  
          });
  
  
          grunt.loadNpmTasks('grunt-contrib-concat');
  
          grunt.registerTask('watch', function() {
  
              var args    = process.argv;
              var dir     = args[args.indexOf('--dir') + 1];
  
              // Now update the directory variable above
  
          });
      };
  
  })();
  </code></pre>