Request: 错误：找不到模块“请求”

Linux 深度

安装步骤：

sudo npm install --save request -g
node
> var request = require('request');
Error: Cannot find module 'request'
    at Function.Module._resolveFilename (module.js:440:15)
    at Function.Module._load (module.js:388:25)
    at Module.require (module.js:468:17)
    at require (internal/module.js:20:19)
    at repl:1:15
    at sigintHandlersWrap (vm.js:32:31)
    at sigintHandlersWrap (vm.js:96:12)
    at ContextifyScript.Script.runInContext (vm.js:31:12)
    at REPLServer.defaultEval (repl.js:308:29)
    at bound (domain.js:280:14)
> 

我怎么能要求请求库..？