为何使用 vue xxx 命令的时候出现 Unknown command xxx？

按照教程一步一步的走，但是执行所有vuecli命令的时候都报个不知道命令的错误，但是好像还能继续运行。因为没办法上传截图。我就复制黏贴了。我用的mac系统。好像能运行的情况下。vue init 新项目的时候又出来404~
谢谢各位指点迷津

vue list

  Unknown command list.

  Available official templates:

  ★  browserify - A full-featured Browserify + vueify setup with hot-reload, linting & unit testing.
  ★  browserify-simple - A simple Browserify + vueify setup for quick prototyping.
  ★  pwa - PWA template for vue-cli based on the webpack template
  ★  simple - The simplest possible Vue setup in a single HTML file
  ★  webpack - A full-featured Webpack + vue-loader setup with hot reload, linting, testing & css extraction.
  ★  webpack-simple - A simple Webpack + vue-loader setup for quick prototyping.

vue init webpack vuejs-essential

  Unknown command init.

   vue-cli · Failed to download repo vuejs-templates/[object Object]: Response code 404 (Not Found)