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dmesg.md 6.30 KB

# dmesg<a name="EN-US_TOPIC_0000001052530284"></a>

-   [Command Function](#section4643204919313)
-   [Syntax](#section6553153635)
-   [Parameter Description](#section208971157532)
-   [Usage](#section213115219413)
-   [Example](#section13736564418)
-   [Output](#section194005101413)

## Command Function<a name="section4643204919313"></a>

This command is used to control the dmesg buffer of the kernel.

## Syntax<a name="section6553153635"></a>

dmesg

dmesg \[_-c/-C/-D/-E/-L/-U_\]

dmesg -s \[_size_\]

dmesg -l \[_level_\]

dmesg \> \[_fileA_\]

## Parameter Description<a name="section208971157532"></a>

**Table  1**  Parameters

<a name="table3900mcpsimp"></a>
<table><thead align="left"><tr id="row3906mcpsimp"><th class="cellrowborder" valign="top" width="21%" id="mcps1.2.4.1.1"><p id="p3908mcpsimp"><a name="p3908mcpsimp"></a><a name="p3908mcpsimp"></a><strong id="b1396020482284"><a name="b1396020482284"></a><a name="b1396020482284"></a>Parameter</strong></p>
</th>
<th class="cellrowborder" valign="top" width="52%" id="mcps1.2.4.1.2"><p id="p3910mcpsimp"><a name="p3910mcpsimp"></a><a name="p3910mcpsimp"></a><strong id="b5731534293"><a name="b5731534293"></a><a name="b5731534293"></a>Description</strong></p>
</th>
<th class="cellrowborder" valign="top" width="27%" id="mcps1.2.4.1.3"><p id="p3912mcpsimp"><a name="p3912mcpsimp"></a><a name="p3912mcpsimp"></a><strong id="b46901499297"><a name="b46901499297"></a><a name="b46901499297"></a>Value Range</strong></p>
</th>
</tr>
</thead>
<tbody><tr id="row3913mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3915mcpsimp"><a name="p3915mcpsimp"></a><a name="p3915mcpsimp"></a>-c</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3917mcpsimp"><a name="p3917mcpsimp"></a><a name="p3917mcpsimp"></a>Prints content in the buffer and clears the buffer.</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3919mcpsimp"><a name="p3919mcpsimp"></a><a name="p3919mcpsimp"></a>N/A</p>
</td>
</tr>
<tr id="row3920mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3922mcpsimp"><a name="p3922mcpsimp"></a><a name="p3922mcpsimp"></a>-C</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3924mcpsimp"><a name="p3924mcpsimp"></a><a name="p3924mcpsimp"></a>Clears the buffer.</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3926mcpsimp"><a name="p3926mcpsimp"></a><a name="p3926mcpsimp"></a>N/A</p>
</td>
</tr>
<tr id="row3927mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3929mcpsimp"><a name="p3929mcpsimp"></a><a name="p3929mcpsimp"></a>-D/-E</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3931mcpsimp"><a name="p3931mcpsimp"></a><a name="p3931mcpsimp"></a>Enables or disables printing to the console.</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3933mcpsimp"><a name="p3933mcpsimp"></a><a name="p3933mcpsimp"></a>N/A</p>
</td>
</tr>
<tr id="row3934mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3936mcpsimp"><a name="p3936mcpsimp"></a><a name="p3936mcpsimp"></a>-L/-U</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3938mcpsimp"><a name="p3938mcpsimp"></a><a name="p3938mcpsimp"></a>Enables or disables printing via the serial port.</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3940mcpsimp"><a name="p3940mcpsimp"></a><a name="p3940mcpsimp"></a>N/A</p>
</td>
</tr>
<tr id="row3941mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3943mcpsimp"><a name="p3943mcpsimp"></a><a name="p3943mcpsimp"></a>-s size</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3945mcpsimp"><a name="p3945mcpsimp"></a><a name="p3945mcpsimp"></a>Sets the size of the buffer.</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3947mcpsimp"><a name="p3947mcpsimp"></a><a name="p3947mcpsimp"></a>N/A</p>
</td>
</tr>
<tr id="row3948mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3950mcpsimp"><a name="p3950mcpsimp"></a><a name="p3950mcpsimp"></a>-l level</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3952mcpsimp"><a name="p3952mcpsimp"></a><a name="p3952mcpsimp"></a>Sets the buffering level.</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3954mcpsimp"><a name="p3954mcpsimp"></a><a name="p3954mcpsimp"></a>0 - 5</p>
</td>
</tr>
<tr id="row3955mcpsimp"><td class="cellrowborder" valign="top" width="21%" headers="mcps1.2.4.1.1 "><p id="p3957mcpsimp"><a name="p3957mcpsimp"></a><a name="p3957mcpsimp"></a>&gt; fileA</p>
</td>
<td class="cellrowborder" valign="top" width="52%" headers="mcps1.2.4.1.2 "><p id="p3959mcpsimp"><a name="p3959mcpsimp"></a><a name="p3959mcpsimp"></a>Writes the content in the buffer to a file.</p>
</td>
<td class="cellrowborder" valign="top" width="27%" headers="mcps1.2.4.1.3 "><p id="p3961mcpsimp"><a name="p3961mcpsimp"></a><a name="p3961mcpsimp"></a>N/A</p>
</td>
</tr>
</tbody>
</table>

## Usage<a name="section213115219413"></a>

-   This command depends on  **LOSCFG\_SHELL\_DMESG**. Before running this command, enable the  **Enable Shell dmesg**  configuration item using  **menuconfig**.

Debug  ---\> Enable a Debug Version ---\> Enable Shell ---\> Enable Shell dmesg

-   If the parameters are not specified, all content in the buffer is printed.
-   The parameters followed by hyphens \(-\) are mutually exclusive.
    1.  Before writing content to a file, ensure that the file system has been mounted.
    2.  Disabling the serial port printing will adversely affect the shell. You are advised to set up a connection using Telnet before disabling the serial port.

## Example<a name="section13736564418"></a>

Enter  **dmesg \> /usr/dmesg.log**.

## Output<a name="section194005101413"></a>

**Figure  1**  Writing dmesg content to a file<a name="fig11150135113566"></a>  
![](figures/writing-dmesg-content-to-a-file.png "writing-dmesg-content-to-a-file")

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提交于 2021-03-12 17:59 . !197 Docs Update version 1.0.1

dmesg

Command Function
Syntax
Parameter Description
Usage
Example
Output

Command Function

This command is used to control the dmesg buffer of the kernel.

Syntax

dmesg

dmesg [-c/-C/-D/-E/-L/-U]

dmesg -s [size]

dmesg -l [level]

dmesg > [fileA]

Parameter Description

Table 1 Parameters

Parameter	Description	Value Range
-c	Prints content in the buffer and clears the buffer.	N/A
-C	Clears the buffer.	N/A
-D/-E	Enables or disables printing to the console.	N/A
-L/-U	Enables or disables printing via the serial port.	N/A
-s size	Sets the size of the buffer.	N/A
-l level	Sets the buffering level.	0 - 5
> fileA	Writes the content in the buffer to a file.	N/A

Usage

This command depends on LOSCFG_SHELL_DMESG. Before running this command, enable the Enable Shell dmesg configuration item using menuconfig.

Debug ---> Enable a Debug Version ---> Enable Shell ---> Enable Shell dmesg
If the parameters are not specified, all content in the buffer is printed.
The parameters followed by hyphens (-) are mutually exclusive.
1. Before writing content to a file, ensure that the file system has been mounted.
2. Disabling the serial port printing will adversely affect the shell. You are advised to set up a connection using Telnet before disabling the serial port.

Example

Enter dmesg > /usr/dmesg.log.

Output

Figure 1 Writing dmesg content to a file

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