linux环境变量展开

#!/bin/bash

expand_env(){
        to_eval=$1
        final_value=$(eval echo $to_eval)
        until [ "$final_value" = "$to_eval" ]
        do
                        to_eval=$final_value
                        final_value=$(eval echo $to_eval)
        done
        echo $final_value
}

 

来源：https://my.oschina.net/guyongquan/blog/3111785