node 启动报错 listen EACCES 0.0.0.0:810

报错信息

events.js:141
      throw er; // Unhandled 'error' event
      ^

Error: listen EACCES 0.0.0.0:80
    at Object.exports._errnoException (util.js:870:11)
    at exports._exceptionWithHostPort (util.js:893:20)
    at Server._listen2 (net.js:1224:19)
    at listen (net.js:1273:10)
    at net.js:1382:9
    at nextTickCallbackWith3Args (node.js:452:9)
    at process._tickCallback (node.js:358:17)
    at Function.Module.runMain (module.js:444:11)
    at startup (node.js:136:18)
    at node.js:966:3

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1.一种是端口被占用

2.sudo node xx.js  -- 访问1024以下的端口需要root权限