dmesg

Command Function

This command is used to display system boot and running information.

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 Disables or enables printing to the console. N/A
-L/-U Disables or enables printing via the serial port. N/A
-s size Sets the size of the buffer. size specifies the buffer size to set. N/A
-l level Sets the buffering level. [0, 5]
> fileA Writes the content in the buffer to a file. N/A

Usage Guidelines

  • This command can be used only after LOSCFG_SHELL_DMESG is enabled. To enable LOSCFG_SHELL_DMESG, run the make menuconfig command in kernel/liteos_a. In the displayed dialog box, locate the Debug option and set Enable Shell dmesg to Yes. Debug ---> Enable a Debug Version ---> Enable Shell ---> Enable Shell dmesg

  • If no parameter is 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 shell. You are advised to set up a connection using Telnet before disabling the serial port.

Example

Run dmesg> dmesg.log.

Output

Write the content in the buffer to the dmesg.log file.

OHOS # dmesg > dmesg.log
Dmesg write log to dmesg.log success