bla.js

task.create(function ConcatTwoFilesAndThenSomeTask() {
  fs.readFile('some/template', 'utf8', function(err, file1) {
    if (err) throw err;
    
    fs.readFile('something/else', 'utf8', function(err, file2) {
      if (err) throw err;
      
      var data = file1 + '--' + file2;
      data = data.replace(/foo/g, 'bar');
      return data;
    });
  });

}).setCallback(function(err, result) {
  if (err)
    throw err;
  // Do something with the result.
});