Here I get no output and the command runs forever:

```
grunt.registerTask('serve', function () {
    var done = this.async();

    grunt.util.spawn({
        cmd: 'jekyll',
        args: ['serve'],
        stdio: 'inherit'
    }, function (err, res, exit_code) {
        res.stdout && console.info(res.stdout);
        exit_code && console.error(res.stderr);
        done(err);
    });
});

```

I want output (and the command to run until error or interrupt).