shell实现猜数字的小游戏

#/*************************************************************************#    > File Name: guessgame.sh#    > Author: liyong#    > Mail: [e-mail]#    > Created Time: 2017-03-22 01:57#    > Last modified: 2017-03-22 01:57randNum=$(date +%s%N)let luckNum=${randNum:0-1:1}echo $luckNumlet num=luckNum+1while [ $luckNum -ne $num ];do    read -p'Please input a num: ' num     #expr 当num为0结果非0,故不能作为数字判断的标准   # expr $num + 0 &> /dev/null ||{ echo '请输入数字';exit 2; }   echo $num |grep -E '^[[:digit:]]+$' &> /dev/null ||{ echo '请输入数字';exit 2;}                                                                  if [ $luckNum -eq $num ];then        echo 'Congratulates';        exit;    elif [ $luckNum -gt $num ];then        echo 'The num you input is smaller'    else        echo 'The num you input is bigger'    fi  done