if [ $num -lt 0 ]; then echo "Number $num is negative" elif [ $num -gt 0 ]; then echo "Number $num is positive" else echo "Number $num is zero" fi 让我运行它来涵盖这里的所有三种情况: Running a script with bash elif statement 用逻辑运算符组合多个条件 到目前为止,一切都很好。但...
4. Bash If..then..else..if..then..fi..fi.. If[conditional expression1]then statement1 statement2.elseif[conditional expression2]then statement3.fi fi if 语句和 else 语句可以嵌套在 bash 中。关键字“fi”表示内部 if 语句的结束,所有 if 语句都应以关键字“fi”结束。 上面提到的“if then e...
if[ -n "$mystack" ];then cd ${mystack%% *} echo "$PWD", stack is [$mystack] else echo "stack empty, still in $PWD." fi } 例如,我们要求命令带有参数,除了使用{1?"<message"}以外,下面给出更可读的方式: if [ -z "$1" ]; then echo 'usage: c filename [-N]' exit1 fi 在...
if [ $num -lt 0 ]; then echo "Number $num is negative" elif [ $num -gt 0 ]; then echo "Number $num is positive" else echo "Number $num is zero" fi 让我运行它来涵盖这里的所有三种情况: Running a script with bash elif statement 用逻辑运算符组合多个条件 到目前为止,一切都很好。但...
else statement5 fi You can use this if .. elif.. if , if you want to select one of many blocks of code to execute. It checks expression 1, if it is true executes statement 1,2. If expression1 is false, it checks expression2, and if all the expression is false, then it enters...
if/else是通过判断选择执行或者执行部分代码,可以根据变量、文件名、命令是否执行成功等很多条件进行判断,他的格式如下: ifconditionthenstatements[elifconditionthenstatements...] [elsestatements]fi 和C程序不一样,bash的判断不是通过boolean,而是通过statement,也就是执行命令后的最终状态(exit status)。所有的Linux...
Bash 中的 if..else 语句是这个样子的: if TEST-COMMAND then STATEMENTS1 else STATEMENTS2 fi 如果TEST-COMMAND 为真,那么 STATEMENT1 会被执行;而如果为假,那么 STATEMENT2 就会被执行。对于每一个 if 语句,只能有一个 else 语句与之对应。 让我们给上一个例子加一个 else 语句: #!/bin/bash echo -n...
if[$num-lt0];then echo"Number $num is negative" elif[$num-gt0];then echo"Number $num is positive" else echo"Number $num is zero" fi 让我运行它来涵盖这里的所有三种情况: Running a with bash elif statement 用逻辑运算符组合多个条件 ...
Now I add an else statement in the previous script. This way when you get a non-zero modulus (as odd numbers are not divided by 2), it will enter the else block. #!/bin/bash read -p "Enter the number: " num mod=$(($num%2)) if [ $mod -eq 0 ]; then echo "Number $num...
单分支if语句 if判断条件 if 判断条件; then then statement1 statement1 statement2 或 statement2 ... ... fi fi 双分支的if语句: if判断条件 if判断条件; then then statement1 stament1 statement2 stament2 ... ... else 或 else statement3 stament3...