# umount<a name="ZH-CN_TOPIC_0000001179965855"></a>

-   [命令功能](#section01)
-   [命令格式](#section02)
-   [参数说明](#section03)
-   [使用指南](#section04)
-   [使用实例](#section05)
-   [输出说明](#section06)

## 命令功能<a name="section01"></a>

umount命令用来卸载指定文件系统。

## 命令格式<a name="section02"></a>

umount  \[_-a \[-t TYPE\]_\]  \[_dir_\]

## 参数说明<a name="section03"></a>

**表 1**  参数说明

<a name="table1713mcpsimp"></a>
<table><thead align="left"><tr id="row1719mcpsimp"><th class="cellrowborder" valign="top" width="21%" id="mcps1.2.4.1.1"><p id="p1721mcpsimp"><a name="p1721mcpsimp"></a><a name="p1721mcpsimp"></a>参数</p>
</th>
<th class="cellrowborder" valign="top" width="52%" id="mcps1.2.4.1.2"><p id="p1723mcpsimp"><a name="p1723mcpsimp"></a><a name="p1723mcpsimp"></a>参数说明</p>
</th>
<th class="cellrowborder" valign="top" width="27%" id="mcps1.2.4.1.3"><p id="p1725mcpsimp"><a name="p1725mcpsimp"></a><a name="p1725mcpsimp"></a>取值范围</p>
</th>
</tr>
</thead>
<tbody><tr id="row451mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p2500105121818"><a name="p2500105121818"></a><a name="p2500105121818"></a>--help</p>
</td>
<td class="cellrowborder" valign="top" width="51.92%" headers="mcps1.2.4.1.2 "><p id="p1149945111817"><a name="p1149945111817"></a><a name="p1149945111817"></a>查看umount命令支持的参数列表。</p>
</td>
<td class="cellrowborder" valign="top" width="27.08%" headers="mcps1.2.4.1.3 "><p id="p749810571812"><a name="p749810571812"></a><a name="p749810571812"></a>N/A</p>
</td>
</tr>
<tr id="row1726mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p1728mcpsimp"><a name="p1728mcpsimp"></a><a name="p1728mcpsimp"></a>-a</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p1730mcpsimp"><a name="p1730mcpsimp"></a><a name="p1730mcpsimp"></a>卸载所有已挂载的目录。</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p1732mcpsimp"><a name="p1732mcpsimp"></a><a name="p1732mcpsimp"></a>N/A</p>
</td>
</tr>
</tr>
<tr id="row1726mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p1728mcpsimp"><a name="p1728mcpsimp"></a><a name="p1728mcpsimp"></a>-t</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p1730mcpsimp"><a name="p1730mcpsimp"></a><a name="p1730mcpsimp"></a>同-a选项一起使用，限制-a，只卸载-t所指定的文件系统类型。</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p1732mcpsimp"><a name="p1732mcpsimp"></a><a name="p1732mcpsimp"></a>N/A</p>
</td>
</tr>
<tr id="row1726mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p1728mcpsimp"><a name="p1728mcpsimp"></a><a name="p1728mcpsimp"></a>dir</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p1730mcpsimp"><a name="p1730mcpsimp"></a><a name="p1730mcpsimp"></a>需要卸载文件系统对应的目录。</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p1732mcpsimp"><a name="p1732mcpsimp"></a><a name="p1732mcpsimp"></a>系统已挂载的文件系统的目录。</p>
</td>
</tr>
</tbody>
</table>

## 使用指南<a name="section04"></a>

umount后加上需要卸载的指定文件系统的目录，即将指定文件系统卸载。

## 使用实例<a name="section05"></a>

举例：

- umount ./nfs
- umount -a -t nfs ./nfs

## 输出说明<a name="section06"></a>

将已在./nfs挂载的文件系统卸载掉。

**示例 1**  umount输出示例

```shell
OHOS:/$ umount ./nfs/
umount ok
```

**示例 2** umount指定文件类型

```shell
OHOS:/$ umount -a -t nfs ./nfs/
umount ok
```