https://blog.csdn.net/xingkong_hdc/article/details/82531505#commentBox
https://jingyan.baidu.com/article/dca1fa6feaa2dab1a5405269.html
https://www.jianshu.com/p/2ccbfa96211c
https://jingyan.baidu.com/article/09ea3ede6ed5c3c0aede3933.html
https://blog.csdn.net/xingkong_hdc/article/details/82531505#commentBox
https://jingyan.baidu.com/article/dca1fa6feaa2dab1a5405269.html
https://www.jianshu.com/p/2ccbfa96211c
https://jingyan.baidu.com/article/09ea3ede6ed5c3c0aede3933.html
shell腳本獲取腳本所在目錄 執行腳本的父目錄不一定是當前的工作目錄。 url=$(dirname $(readlink -f $0))