shell脚本实现传参(参数不限)

1.传递一个参数

root@wadequ-ThinkPad-L13:~# cat param.sh 
#!/bin/bash
echo "first param is $0"
echo "secoud param is $1"
echo "all secoud is $#" //总的个数

root@wadequ-ThinkPad-L13:~# bash param.sh a 
first param is param.sh
secoud param is a
all secoud is 1

2.传递两个参数且对于参数不够时提示使用用法

root@wadequ-ThinkPad-L13:~# cat param.sh 
#!/bin/bash
if [ "$#" -eq "2" ];then
        echo "first param is $0"
        echo "secoud param is $1"
        echo "all count is $#"
else
        echo "Usage: `basename $0` param1 param2"
        echo "You provided $# parameters,but 2 are required."
fi
//传一个参数
root@wadequ-ThinkPad-L13:~# bash param.sh a 
Usage: param.sh param1 param2
You provided 1 parameters,but 2 are required.
//传两个参数
root@wadequ-ThinkPad-L13:~# bash param.sh a  b
first param is param.sh
secoud param is a
all count is 2

3.传递多个参数(不限参数个数)

//使用shift 命令的方法  位置参数可以用shift命令左移
// shift 命令每执行一次，变量的个数($#)减一 而变量值提前一位
root@wadequ-ThinkPad-L13:~# cat param.sh 
#!/bin/bash
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
//脚本测试
root@wadequ-ThinkPad-L13:~# bash param.sh a 
filename is param.sh
params is  1 参数
参数序号为 1 是 a
root@wadequ-ThinkPad-L13:~# bash param.sh a b
filename is param.sh
params is  2 参数
参数序号为 1 是 a
参数序号为 2 是 b
root@wadequ-ThinkPad-L13:~# bash param.sh a b c
filename is param.sh
params is  3 参数
参数序号为 1 是 a
参数序号为 2 是 b
参数序号为 3 是 c