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
