title: grunt create and run less compile task
body: <p>i am very new to grunt and i wanted to achieve following goal</p>
  
  <ul>
  <li>iterate every directory in pointed location</li>
  <li>compile less file to css</li>
  </ul>
  
  <p>source:</p>
  
  <ul>
  <li>theme 1
  
  <ul>
  <li>file.less</li>
  </ul></li>
  <li>theme 2
  
  <ul>
  <li>file.less</li>
  </ul></li>
  <li>theme 3
  
  <ul>
  <li>file.less</li>
  </ul></li>
  </ul>
  
  <p>after processing:</p>
  
  <ul>
  <li>theme 1
  
  <ul>
  <li>file.less</li>
  <li>out.css</li>
  </ul></li>
  <li>theme 2
  
  <ul>
  <li>file.less</li>
  <li>out.css</li>
  </ul></li>
  <li>theme 3
  
  <ul>
  <li>file.less</li>
  <li>out.css</li>
  </ul></li>
  </ul>
  
  <p>I read somewhere that grunt does that, this is my entire run.js file:</p>
  
  <pre><code>var grunt = require('grunt'),
      less = require('less');
  
    grunt.initConfig({
      less: {
        compileCore: {
          options: {
            strictMath: true
          },
          files: [{
            expand: true,
            src: ['themes/**/file.less'], 
            ext: '.css',
            extDot: 'first'
          }]
        }
    }
    });
  
    grunt.registerTask('default', ['less']);
  
    grunt.task.run('default');
  </code></pre>
  
  <p>it doesnt give any errors but it doesnt work either, how can i make this to work? (again, i have no exprience with grunt whatsoever, yet)</p>
  
  <p>if its possible also to achieve this goal with just command line execution (without runing node.js file) that would be good too ;)</p>