webpack全局安装了，使用命令时却提示安装脚手架
全局安装了webpack ，使用webpack的时候，却有如下的提示
One CLI for webpack must be installed. These are recommended choices, delivered as separate packages: - webpack-cli (https://github.com/webpack/webpack-cli) The original webpack full-featured CLI. We will use "npm" to install the CLI via "npm install -D". Do you want to install 'webpack-cli' (yes/no): n You need to install 'webpack-cli' to use webpack via CLI. You can also install the CLI manually.
这里提示安装 webpack-cli// 是因为到了webpack4, webpack 已经将 webpack 命令行相关的内容都迁移到 webpack-cli，所以除了 webpack 外，我们还需要安装 webpack-cli：
这个时候我们可以执行下面的命令
npm install --save-dev webpack-cli -g
