shell脚本函数传参-蒲公英云

shell脚本函数传参

末蓝、 2022-01-14 04:55 543阅读 0赞

函数可以提高代码复用，在python、java中比较常见。
shell脚本也有函数，可以将一组命令集或语句形成一个可用代码块。

定义格式

函数名(){
    command1
    command2
    ...
    commandN
    [ return value ]
}

函数返回值

可以显示增加return语句；如果不加，则将最后一条命令运行结果作为返回值（一般为0，如果执行失败则返回错误代码）。
return后跟数值（0-255）

#! /bin/bash
function test(){
        echo "The first param is $1"
        return 111
}
test 1
echo "The return of test is $?"

运行结果：

[root@master ~]# sh test_function.sh 
The first param is 1
The return of test is 111

Shell函数传参

在Shell中，调用函数时可以向其传递参数。在函数体内部，通过 $n 的形式来获取参数的值，例如，$1表示第一个参数，$2表示第二个参数…即使用位置参数来实现参数传递。

#! /bin/bash
function test(){
        echo "The first param is $1"
        echo "The second param is $2"
        echo "The third param is $3"
        echo "The forth param is $4"
        echo "The fifth param is $5"
        echo "The sixth param is $6"
        echo "The seventh param is $7"
        echo "The eigth param is $8"
        echo "The ninth param is $9"
        echo "The tength param is $10"
        echo "The 11th param is $11"
        return 111
}
test 1 2 3 4 5 6 7 8 9 55 54
echo "The return of test is $?"

运行结果：
[root@master ~]# sh test_function.sh
The first param is 1
The second param is 2
The third param is 3
The forth param is 4
The fifth param is 5
The sixth param is 6
The seventh param is 7
The eigth param is 8
The ninth param is 9
The tength param is 10
The 11th param is 11

注意，$10 不能获取第十个参数，如上结果中$10，打印结果为10。
获取第十个参数需要${10}。

正确姿势，当n>=10时，需要使用${n}来获取参数：

#! /bin/bash
function test(){
        echo "The first param is $1"
        echo "The second param is $2"
        echo "The third param is $3"
        echo "The forth param is $4"
        echo "The fifth param is $5"
        echo "The sixth param is $6"
        echo "The seventh param is $7"
        echo "The eigth param is $8"
        echo "The ninth param is $9"
        echo "The tength param is ${10}"
        echo "The 11th param is ${11}"
        return 111
}
test 1 2 3 4 5 6 7 8 9 55 54
echo "The return of test is $?"