linux 系统中while循环示例

1、linux系统中while循环示例

[root@linuxprobe test]# ls
test.sh
[root@linuxprobe test]# cat test.sh
#!/bin/bash
echo "the scale of price is 0-999!"  ## 输入内容提示
PRICE=`expr $RANDOM % 1000`  ## 生成随机的范围变量，0-999
COUNTS=0  ## 定义初始次数为0
while true
do
read -p "please input your answer:" ANSWER
let COUNTS++  ## 等价于 COUNTS=$[ $COUNTS + 1 ]
if [ $ANSWER -eq $PRICE ]
then
echo "right,the price is $PRICE!"
echo "you guess $COUNTS times!"
exit 0 ## 等价于 exit / exit 1 / break
elif [ $ANSWER -gt $PRICE ]
then
echo "high!"
else
echo "low!"
fi
done
[root@linuxprobe test]# bash test.sh
the scale of price is 0-999!
please input your answer:500
low!
please input your answer:700
low!
please input your answer:800
high!
please input your answer:750
high!
please input your answer:730
low!
please input your answer:740
high!
please input your answer:735
right,the price is 735!
you guess 7 times!