# Shell脚本的参数

shell脚本在shell中执行时，可以传递0个或多个参数\
​

```shell
sh script.sh param1 param2 ...
```

* ​

​

在脚本中，通过 `$n` 的方式获取脚本的参数

```shell
#!/bin/zsh

echo "Shell 传递参数实例！";
echo "执行的文件名：$0";
echo "第一个参数为：$1";
echo "第二个参数为：$2";
echo "第三个参数为：$3";
```

![截屏2022-01-13 18.17.03.png](https://cdn.nlark.com/yuque/0/2022/png/22724999/1642069039157-782838b1-356e-441a-bc09-e9f3782e7803.png#clientId=uc2a163a2-2560-4\&from=drop\&id=u602d0c2c\&margin=%5Bobject%20Object%5D\&name=%E6%88%AA%E5%B1%8F2022-01-13%2018.17.03.png\&originHeight=340\&originWidth=984\&originalType=binary\&ratio=1\&size=97967\&status=done\&style=none\&taskId=u1d6507d8-13bd-472a-8f08-c3e90808c88)

* ​`$0` : 执行的文件路径
* `$1` \~ `$n` : 脚本的参数
* `$#` : 参数的数量
* `$$` : 脚本运行的当前进程ID号
* `$!` : 后台运行的最后一个进程的ID号
* `$-` : 显示Shell使用的当前选项
* `$?` ： 上一条命令或脚本的退出状态（0标识没有错误，其他任何值标识有错误）

```shell
# 退出返回1 错误
exit 1
# 退出返回0 没有错误
exit 0
```

* `$*` : 以一个单字符串显示所有向脚本传递的参数。\
  如"$\*"用「"」括起来的情况、以"$1 $2 … $n"的形式输出所有参数。
* `$@` : 与$\*相同，但是使用时加引号，并在引号中返回每个参数。\
  如"$@"用「"」括起来的情况、以"$1" "$2" … "$n" 的形式输出所有参数。


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