source 你的脚本，不要像 ./foo.sh 或 那样执行sh foo.sh

source your script, don't execute it like ./foo.sh or sh foo.sh

如果你这样执行你的脚本，它会在子 shell 中运行，而不是你当前的.

If you execute your script like that, it is running in sub-shell, not your current.

source foo.sh  

对你有用.