#!/bin/bash
death_age=80
read -p "Your name: " name
read -p "You age: " age
expr $age + 1 &>/dev/null
if [ $? -eq 0 ];then
	echo "You can still live for " $(($death_age-$age)) "years....."
else
        echo "你输入错误，请重新输入"
	exit 1
fi