运行 npm install -g appium 的 get 请求就是 304 错误.

npm http GET https://registry.npmjs.org/appium
npm http 304 https://registry.npmjs.org/appium
npm ERR! Error: EACCES, mkdir '/usr/local/lib/node_modules/appium'
npm ERR! { [Error: EACCES, mkdir '/usr/local/lib/node_modules/appium']
npm ERR! errno: 3,
npm ERR! code: 'EACCES',
npm ERR! path: '/usr/local/lib/node_modules/appium',
npm ERR! fstream_type: 'Directory',
npm ERR! fstream_path: '/usr/local/lib/node_modules/appium',
npm ERR! fstream_class: 'DirWriter',
npm ERR! fstream_stack:
npm ERR! [ '/usr/local/lib/node_modules/npm/node_modules/fstream/lib/dir-writer.js:36:23',
npm ERR! '/usr/local/lib/node_modules/npm/node_modules/mkdirp/index.js:37:53',
npm ERR! 'Object.oncomplete (fs.js:107:15)' ] }
npm ERR!
npm ERR! Please try running this command again as root/Administrator.

求大神解答,坐等.....谢谢!!