按照官网的步骤来安装的：

当创建了已经项目，项目中已经包含了gruntfile.js和packge.json等文件，当时在项目下执行grunt时候出现了下班错误提示，在node_modules中已经存在了grunt和grunt-cli

grunt-cli: The grunt command line interface. (v0.1.9)

Fatal error: Unable to find local grunt.

If you're seeing this message, either a Gruntfile wasn't found or grunt
hasn't been installed locally to your project. For more information about
installing and configuring grunt, please see the Getting Started guide