语法：
case "字符串变量" in
值1)指令
;;
值2)指令
;;
值*)指令
;;
esac
下面我们来作一个小脚本：
#!/bin/bash
read -p "please input one the number:" a
case "$a" in
1)
echo "you input the number is 1"
;;
2)
echo "you input the number is 2"
;;
[3-9])
echo "you input the number is $a"
;;
*)
echo "you input the number more than 10!"
;;
esac
下面是这个脚本的执行效果：
[root@zhouyu shell]# sh case.sh
please input one the number:1
you input the number is 1
[root@zhouyu shell]# sh case.sh
please input one the number:2
you input the number is 2
[root@zhouyu shell]# sh case.sh
please input one the number:3
you input the number is 3
[root@zhouyu shell]# sh case.sh
please input one the number:4
you input the number is 4
[root@zhouyu shell]# sh case.sh
please input one the number:10
you input the number more than 10!
[root@zhouyu shell]#
如果我们用if语句去实现的话是这样的
#!/bin/bash
read -p "please input one the number:" a
if [ $a -eq 1 ];then
echo "you input the number is 1"
elif [ $a -eq 2 ];then
echo "you input the number is 2"
elif [ $a -ge 3 -a $a -le 9 ];then
echo "you input the number is $a"
else
echo "you input the number more than 10!"
fi
"case_if.sh" 11L, 283C 已写入
[root@zhouyu shell]# sh case_if.sh
please input one the number:1
you input the number is 1
[root@zhouyu shell]# sh case_if.sh
please input one the number:2
you input the number is 2
[root@zhouyu shell]# sh case_if.sh
please input one the number:3
you input the number is 3
[root@zhouyu shell]# sh case_if.sh
please input one the number:4
you input the number is 4
[root@zhouyu shell]# sh case_if.sh
please input one the number:10
you input the number more than 10!
通过上面我们可以知道，其实用case的话比较快，因为它不用比较，其实if的功能case可以实现，只是有时候用case比较麻烦，所以就用if语句
本文出自 “爱周瑜” 博客，请务必保留此出处http://izhouyu.blog.51cto.com/10318932/1891998
原文：http://izhouyu.blog.51cto.com/10318932/1891998