How to resolve “You need to have Ruby and Sass installed and in your PATH for this task to work” Warning?

我mac上创建Grunt项目的时候使用npm install在项目文件夹下下载项目所依赖的框架出现了下面的异常

No problems so far, but as soon as I try to run the sass:dist task, I get this warning:

Warning: You need to have Ruby and Sass installed and in your PATH for

this task to work. More info:

https://github.com/gruntjs/grunt-contrib-sass Use --force

to continue.

解决方法是，要在确保Ruby安装的情况下执行

sudo gem install sass