遇到以下问题：
npm ERR! path /Users/aven/node-red/node_modules/onetime
npm ERR! code EACCES
npm ERR! errno -13
npm ERR! syscall access
npm ERR! Error: EACCES: permission denied, access '/Users/aven/node-red/node_modules/onetime'
npm ERR! { Error: EACCES: permission denied, access '/Users/aven/node-red/node_modules/onetime'
npm ERR! stack: 'Error: EACCES: permission denied, access \'/Users/aven/node-red/node_modules/onetime\'',
npm ERR! errno: -13,
npm ERR! code: 'EACCES',
npm ERR! syscall: 'access',
npm ERR! path: '/Users/aven/node-red/node_modules/onetime' }
npm ERR!
npm ERR! Please try running this command again as root/Administrator.
注意最后一句提示：请尝试以root / Administrator身份再次运行此命令。
在命令前加上 sudo
sudo npm install --save-dev grunt不过这样子可能还是不行，你需要这样：
sudo npm install --unsafe-perm=true --save-dev grunt或许你还是会遇到错误，请尝试这样：
sudo npm install --unsafe-perm=true --allow-root --save-dev grunt
