webpack-dev-server detect file changes and auto compile in ubuntu 16.04

solution.md

$ webpack-dev-server --content-base ./ --port <port> --hot

#检测文件改动webpack 是否察觉 webpack --watch --progress

#如果改动文件(并保存), webpack没有察觉 , 则执行

$ echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

useful link https://stackoverflow.com/questions/29722755/webpack-dev-server-does-not-watch-for-my-file-changes https://webpack.github.io/docs/troubleshooting.html#not-enough-watchers