mac 安装hexo，提示npm WARN checkPermissions Missing write access

   输入 $ npm install -g hexo

提示错误：

npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules/hexo
npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules
/usr/local/lib
└── hexo@3.2.0 

npm ERR! Darwin 15.2.0
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "install" "-g" "hexo"
npm ERR! node v5.9.0
npm ERR! npm  v3.7.3
npm ERR! path /usr/local/lib/node_modules/hexo
npm ERR! code EACCES
npm ERR! errno -13
npm ERR! syscall access

npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules/hexo'
npm ERR!     at Error (native)
npm ERR!  { [Error: EACCES: permission denied, access '/usr/local/lib/node_modules/hexo']
npm ERR!   errno: -13,
npm ERR!   code: 'EACCES',
npm ERR!   syscall: 'access',
npm ERR!   path: '/usr/local/lib/node_modules/hexo' }
npm ERR! 
npm ERR! Please try running this command again as root/Administrator.

npm ERR! Please include the following file with any support request:
npm ERR!     /Users/jason/npm-debug.log

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$ sudo npm install -g hero-cli
输入上面命令安装就行了

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请切换到root用户执行

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npm说是，最好不要用root来执行，否则会很麻烦，请参考这个解决方法