dmesg.md

# dmesg
## 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