# col

过滤控制字符

## 补充说明

**col命令** 是一个标准输入文本过滤器，它从标注输入设备读取文本内容，并把内容显示到标注输出设备。在许多UNIX说明文件里，都有RLF控制字符。当我们运用shell特殊字符`>`和`>>`，把说明文件的内容输出成纯文本文件时，控制字符会变成乱码，col命令则能有效滤除这些控制字符。

### 语法

```
col(选项)
```

### 选项

```
-b：过滤掉所有的控制字符，包括RLF和HRLF；
-f：滤掉RLF字符，但允许将HRLF字符呈现出来；
-x：以多个空格字符来表示跳格字符；
-l<缓冲区列数>：预设的内存缓冲区有128列，用户可以自行指定缓冲区的大小。
```


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