1.运行vue的时候提示

vue create hello-world
zsh: command not found: vue

2.重新安装

sudo npm install -g vue-cli
Password:
npm WARN deprecated vue-cli@2.9.6: This package has been deprecated in favour of @vue/cli
npm WARN deprecated coffee-script@1.12.7: CoffeeScript on NPM has moved to "coffeescript" (no hyphen)
/usr/local/bin/vue -> /usr/local/lib/node_modules/vue-cli/bin/vue
/usr/local/bin/vue-init -> /usr/local/lib/node_modules/vue-cli/bin/vue-init
/usr/local/bin/vue-list -> /usr/local/lib/node_modules/vue-cli/bin/vue-list
+ vue-cli@2.9.6
added 241 packages from 206 contributors in 13.711s

3.查看帮助

vue -help
Usage: vue <command> [options]

Options:
  -V, --version  output the version number
  -h, --help     output usage information

Commands:
  init           generate a new project from a template
  list           list available official templates
  build          prototype a new project
  create         (for v3 warning only)
  help [cmd]     display help for [cmd]