Linux dmesg command details how to use Linux dmesg command

The kernel stores the boot information in the ring buffer. You can use dmesg to view the information if you cannot view it at startup. The boot information is also saved in the/var/log directory and named dmesg.

Syntax

Dmesg [-cn] [-s <buffer size>]

Parameter description:

• -C: After the information is displayed, clear the content in the ring buffer.
• -S <buffer size> is set to 8196, which is equal to the ring buffer size.
• -N: set the record information level.

Instance

Display boot information

# Dmesg | less

WARNING: terminal is not fully functional

[2, 0.000000] Initializing cgroup subsys cpuset

[2, 0.000000] Initializing cgroup subsys cpu

[0.000000] Linux version 2.6.32-21-generic (buildd @ rothera) (gcc version 4.4.3 (Ub untu 4.4.3-4ubuntu5 )) # 32-Ubuntu SMP Fri Apr 16 08:10:02 UTC 2010 (Ubuntu 2.6.32-21.3 2-generic 2.6.32.11 + drm33.2)

[2, 0.000000] KERNEL supported cpus:

[2, 0.000000] Intel GenuineIntel

[2, 0.000000] AMD AuthenticAMD

[2, 0.000000] NSC Geode by NSC

[0.000000] Cyrix CyrixInstead

[1, 0.000000] Centaur CentaurHauls

[2, 0.000000] Transmeta GenuineTMx86

[2, 0.000000] Transmeta TransmetaCPU

[0.000000] UMC

[0.000000] BIOS-provided physical RAM map:

[0.000000] BIOS-e820: 0000000000000000-000000000009f800 (usable)

[0.000000] BIOS-e820: 000000000009f800-00000000000a0000 (reserved)

[0.000000] BIOS-e820: 00000000000ca000-00000000000cc000 (reserved)

[0.000000] BIOS-e820: 00000000000dc000-00000000000e0000 (reserved)

[0.000000] BIOS-e820: 00000000000e4000-0000000000100000 (reserved)

[0.000000] BIOS-e820: 0000000000100000-000000003fef0000 (usable)

[0.000000] BIOS-e820: %%3fef0000-%%3feff000 (ACPI data)

[0.000000] BIOS-e820: %%3feff000-%%3ff00000 (acpi nvs)

...... Omitted content

Display boot information

# Pwd // view the current directory

/Home/hnlinux/

# Dmesg> boot. msg // Save the boot information to the boot. msg file.

# Ls // display the current directory file

Boot. msg