操作系统 Shell
https://www.ibm.com/support/knowledgecenter/zh/ssw_aix_72/com.ibm.aix.osdevice/shells.htm
Google的shell（编程）风格指南
https://www.jianshu.com/p/09abb264ab95
Shell代码规范
https://blog.csdn.net/wirelessqa/article/details/18863403
Linux中的shell脚本编程之函数
http://blog.51cto.com/1992tao/1841183
Shell 风格指南
https://zh-google-styleguide.readthedocs.io/en/latest/google-shell-styleguide/contents/
设计模式 – shell脚本的设计模式或最佳实践
https://codeday.me/bug/20180815/221274.html
