example grunt file for running tasks in subdirectories, each which have their own grunt file

Gruntfile.js

module.exports = function(grunt) {

	grunt.registerTask('buildapp', function(dir) {
		var done = this.async();

		grunt.log.writeln('processing ' + dir);

		grunt.util.spawn({
			grunt: true,
			args:['jshint', 'build', 'test', 'deploy'],
			opts: {
				cwd: dir
			}
		},

		function(err, result, code) {
			if (err == null) {
				grunt.log.writeln('processed ' + dir);
				done();
			}
			else {
				grunt.log.writeln('processing ' + dir + ' failed: ' + code);
				done(false);
			}
		})
	});

	grunt.registerTask('build', function() {
		grunt.task.run(['buildapp:apps/framework']);
		grunt.task.run(['buildapp:apps/foo']);
	});

	grunt.registerTask('default', ['build']);
};

package.json

{
  "name": "foosuite",
  "version": "0.0.0",
  "dependencies": {},
  "devDependencies": {
    "grunt": "~0.4.1",
    "grunt-cli": "~0.1.9"
  },
  "engines": {
    "node": ">=0.8.0"
  }
}