# expr

一款表达式计算工具

## 补充说明

**expr命令** 是一款表达式计算工具，使用它完成表达式的求值操作。

expr的常用运算符：

* 加法运算：`+`
* 减法运算：`-`
* 乘法运算：`\*`
* 除法运算：`/`
* 求摸（取余）运算：`%`

### 语法

```
expr(选项)(参数)
```

### 选项

```
--help：显示指令的帮助信息；
--version：显示指令版本信息。
```

### 参数

表达式：要求值的表达式。

### 实例

```
result=`expr 2 + 3`
result=$(expr $no1 + 5)
```


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