【shell编程】if语句

正文

if语句

if 语句通过关系运算符判断表达式的真假来决定执行哪个分支。Shell 有三种 if ... else 语句:

 if ... fi 语句;
 if ... else ... fi 语句;
 if ... elif ... else ... fi 语句。

 

if ... else ... fi 语句的语法:

if [ expression ]
then
   Statement(s) to be executed if expression is true
else
   Statement(s) to be executed if expression is not true
fi

 

 if ... elif ... fi 语句可以对多个条件进行判断,语法:

if [ expression 1 ]
then
   Statement(s) to be executed if expression 1 is true
elif [ expression 2 ]
then
   Statement(s) to be executed if expression 2 is true
elif [ expression 3 ]
then
   Statement(s) to be executed if expression 3 is true
else
   Statement(s) to be executed if no expression is true
fi

参考资料

 

posted @   苏格拉底的落泪  阅读(38)  评论(0编辑  收藏  举报
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