00_bash_shell_script

https://mug896.github.io/bash-shell/index.html

Linux Command Line

https://github.com/santosh373/Linux-Basics/blob/master/Shotts%20W.%20E.%20Jr.%20-%20The%20Linux%20Command%20Line%20-%20A%20Complete%20Introduction%20-%202012.pdf

book_unix-linux-shellscript

https://github.com/AstinCHOI/book_unix-linux-shellscript