【shell】Linux shell tips

shell特殊变量：Shell $0, $#, $*, $@, $?, $$和命令行参数

https://www.cnblogs.com/davygeek/p/5670212.html

What are PID and PPID?

https://linux.cn/article-5051-1.html

https://riptutorial.com/bash/example/16878/-ppid

https://delightlylinux.wordpress.com/2012/06/25/what-is-pid-and-ppid/

shell变量的初始值赋值

https://blog.csdn.net/xy8310292/article/details/80671664

https://blog.csdn.net/joe_007/article/details/8773594

shell脚本里面PS1="${x##*/}\$"的意思是什么？

https://zhidao.baidu.com/question/746509459296838252.html

What is the meaning of “${1#*-}” in BASH？

https://stackoverflow.com/questions/41806725/what-is-the-meaning-of-1-in-bash

https://wiki.bash-hackers.org/syntax/pe

https://www.jianshu.com/p/10d7405fc36b

Linux shell：${var1##*：} ${bz1%，*}的意思

https://blog.csdn.net/wmjcode/article/details/80662501

Linux 中 if [ "x${var}" = "x" ] 什么意思?

https://zhidao.baidu.com/question/510807608.html

关于shell脚本中shift 用法

Linux shell脚本中shift的用法说明

https://www.cnblogs.com/image-eye/archive/2011/08/20/2147153.html

https://blog.csdn.net/zhu_xun/article/details/24796235

https://reb12345reb.iteye.com/blog/2118179