# dmesg - [Command Function](#section4643204919313) - [Syntax](#section6553153635) - [Parameters](#section208971157532) - [Usage](#section213115219413) - [Example](#section13736564418) - [Output](#section194005101413) ## 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 \> \[_fileA_\] ## Parameters **Table 1** Parameter description

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 using this command, select **Enable Shell dmesg** on **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 Example: Run **dmesg \> /usr/dmesg.log**. ## Output **Figure 1** Writing dmesg content to a file ![](figure/writing-dmesg-content-to-a-file.png "writing-dmesg-content-to-a-file")