3.3.3 逻辑组合
学习目标
这一节，我们从 基础知识、简单实践、小结 三个方面来学习。
基础知识
简介
所谓的条件组合，指的是在同一个场景下的多个条件的综合判断效果。语法解析
方法1：
[ 条件1 -a 条件2 ] - 两个条件都为真，整体为真，否则为假
[ 条件1 -o 条件2 ] - 两个条件都为假，整体为假，否则为真
方法2：
[[ 条件1 && 条件2 ]] - 两个条件都为真，整体为真，否则为假
[[ 条件1 || 条件2 ]] - 两个条件都为假，整体为假，否则为真简单实践
实践1-[]组合实践
[root@localhost ~]# user=root pass=123456
[root@localhost ~]# [ $user == "root" -a $pass == "123456" ]
[root@localhost ~]# echo $?
0
[root@localhost ~]# [ $user == "root" -a $pass == "1234567" ]
[root@localhost ~]# echo $?
1
[root@localhost ~]# [ $user == "root" -o $pass == "1234567" ]
[root@localhost ~]# echo $?
0
[root@localhost ~]# [ $user == "root1" -o $pass == "1234567" ]
[root@localhost ~]# echo $?
1实践2 - [[]]组合实践
[root@localhost ~]# [[ $user == "root" && $pass == "123456" ]]
[root@localhost ~]# echo $?
0
[root@localhost ~]# [[ $user == "root" && $pass == "1234567" ]]
[root@localhost ~]# echo $?
1
[root@localhost ~]# [[ $user == "root" || $pass == "1234567" ]]
[root@localhost ~]# echo $?
0
[root@localhost ~]# [[ $user == "root1" || $pass == "1234567" ]]
[root@localhost ~]# echo $?
1
