Dmesg - Display or control the kernel ring buffer - show bootup messages

Usage

dmesg [options]

Flags

Options:
 -C, --clear                 clear the kernel ring buffer
 -c, --read-clear            read and clear all messages
 -D, --console-off           disable printing messages to console
 -E, --console-on            enable printing messages to console
 -F, --file <file>           use the file instead of the kernel log buffer
 -f, --facility <list>       restrict output to defined facilities
 -H, --human                 human readable output
 -k, --kernel                display kernel messages
 -L, --color[=<when>]        colorize messages (auto, always or never)
                               colors are enabled by default
 -l, --level <list>          restrict output to defined levels
 -n, --console-level <level> set level of messages printed to console
 -P, --nopager               do not pipe output into a pager
 -p, --force-prefix          force timestamp output on each line of multi-line messages
 -r, --raw                   print the raw message buffer
 -S, --syslog                force to use syslog(2) rather than /dev/kmsg
 -s, --buffer-size <size>    buffer size to query the kernel ring buffer
 -u, --userspace             display userspace messages
 -w, --follow                wait for new messages
 -x, --decode                decode facility and level to readable string
 -d, --show-delta            show time delta between printed messages
 -e, --reltime               show local time and time delta in readable format
 -T, --ctime                 show human-readable timestamp (may be inaccurate!)
 -t, --notime                don't show any timestamp with messages
     --time-format <format>  show timestamp using the given format:
                               [delta|reltime|ctime|notime|iso]
Suspending/resume will make ctime and iso timestamps inaccurate.

 -h, --help                  display this help
 -V, --version               display version

Supported log facilities:
    kern - kernel messages
    user - random user-level messages
    mail - mail system
  daemon - system daemons
    auth - security/authorization messages
  syslog - messages generated internally by syslogd
     lpr - line printer subsystem
    news - network news subsystem

Supported log levels (priorities):
   emerg - system is unusable
   alert - action must be taken immediately
    crit - critical conditions
     err - error conditions
    warn - warning conditions
  notice - normal but significant condition
    info - informational
   debug - debug-level messages

For more details see dmesg(1).

Examples

 dmesg
[    0.000000] microcode: microcode updated early to revision 0xd6, date = 2020-04-27
[    0.000000] Linux version 5.4.0-7634-generic ([email protected]) (gcc version 9.3.0 (Ubuntu 9.3.0-10ubuntu2)) #38~1596560323~20.04~7719dbd-Ubuntu SMP Tue Aug 4 19:12:34 UTC 2 (Ubuntu 5.4.0-7634.38~1596560323~20.04~7719dbd-generic 5.4.41)
[    0.000000] Command line: initrd=\EFI\Pop_OS-5d9b752f-4284-420f-98f4-ce080478be72\initrd.img root=UUID=5d9b752f-4284-420f-98f4-ce080478be72 ro quiet loglevel=0 systemd.show_status=false splash
[    0.000000] KERNEL supported cpus:
[    0.000000]   Intel GenuineIntel
[    0.000000]   AMD AuthenticAMD
[    0.000000]   Hygon HygonGenuine
[    0.000000]   Centaur CentaurHauls
[    0.000000]   zhaoxin   Shanghai  
[    0.000000] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
[...]

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