一、接收固定长度的参数

[root@svn shell_example]# cat params.sh

#!/bin/bash

#传参测试脚本

echo "My name is `basename $0` -I was called as $0"

echo "My first parameter is : $1"

echo "My second parameter is : $2"

空参数执行

[root@svn shell_example]# sh params.sh

My name is params.sh -I was called as params.sh

My first parameter is :

My second parameter is :

传递2个参数执行

[root@svn shell_example]# sh params.sh one two

My name is params.sh -I was called as params.sh

My first parameter is : one

My second parameter is : two

二、那如果还有参数怎么办呢?还要一个个加上来吗?答案是否定的

以下用法应该不陌生,就是直接执行脚本本身,没有附带任何参数,那么脚本讲抛出帮助信息.即怎么使用此脚本.见红字部分

[root@svn shell_example]# sh params_v2.sh

My name is params_v2.sh -I was called as params_v2.sh

I was called with 0 parameters.

Usage: params_v2.sh first second

You provided 0 parameters,but 2 are required.

代码如下

[root@svn shell_example]# cat params_v2.sh

#!/bin/bash

# 这是个测试脚本传参的测试例子

echo "My name is `basename $0` -I was called as $0"

echo "I was called with $# parameters."
if [ "$#" -eq "2" ];then

    echo "My first parameter is $1"

    echo "My second parameter is $2"

else

    echo "Usage: `basename $0` first second"

    echo "You provided $# parameters,but 2 are required."

fi

详细的执行过程如下
不传参数执行

[root@svn shell_example]# sh params_v2.sh

My name is params_v2.sh -I was called as params_v2.sh

I was called with 0 parameters.

Usage: params_v2.sh first second

You provided 0 parameters,but 2 are required.

传递3个参数执行

[root@svn shell_example]# sh params_v2.sh one two three

My name is params_v2.sh -I was called as params_v2.sh

I was called with 3 parameters.

Usage: params_v2.sh first second

You provided 3 parameters,but 2 are required.

传递2个参数执行

[root@svn shell_example]# sh params_v2.sh one two

My name is params_v2.sh -I was called as params_v2.sh

I was called with 2 parameters.

My first parameter is one

My second parameter is two

问题来了,要是后期还要加参数怎么办呢?或者我也不确定到底会传几个参数.
解决方法如下,详细执行结果如下

[root@svn shell_example]# cat manyparams.sh

#!/bin/bash

#这是个测试脚本传N个参数的例子

echo "我的名字是 `basename $0` - 我是调用自 $0"

echo "我有 $# 参数"
count=1

while [ "$#" -ge "1" ];do

    echo "参数序号为 $count 是 $1"

    let count=count+1

    shift

done

一个参数执行

[root@svn shell_example]# sh manyparams.sh one

我的名字是 manyparams.sh - 我是调用自 manyparams.sh
我有 1 参数
参数序号为 1 是 one

5个参数执行

[root@svn shell_example]# sh manyparams.sh one two three four five

我的名字是 manyparams.sh - 我是调用自 manyparams.sh
我有 5 参数
参数序号为 1 是 one
参数序号为 2 是 two
参数序号为 3 是 three
参数序号为 4 是 four
参数序号为 5 是 five