pydmesg

SUMMARY

Display system message buffer

log [-tdm]
dmesg [-tdm]

DESCRIPTION

This command dumps the kernel log_buf contents in chronological order. The command supports the older log_buf formats, which may or may not contain a timestamp inserted prior to each message, as well as the newer variable-length record format, where the timestamp is contained in each log entry’s header.

-t	Display the message text without the timestamp.
-d	Display the dictionary of key/value pair properties that are optionally appended to a message by the kernel’s dev_printk() function; only applicable to the variable-length record format.
-m	Display the message log level in brackets preceding each message. For the variable-length record format, the level will be displayed in hexadecimal, and depending upon the kernel version, also contains the facility or flags bits.

Examples

Dump the kernel message buffer:

py-crash> log
Linux version 2.2.5-15smp (root@mclinux1) (gcc version egcs-2.91.66 19990
314/Linux (egcs-1.1.2 release)) #1 SMP Thu Aug 26 11:04:37 EDT 1999
Intel MultiProcessor Specification v1.4
    Virtual Wire compatibility mode.
OEM ID: DELL     Product ID: WS 410       APIC at: 0xFEE00000
Processor #0 Pentium(tm) Pro APIC version 17
Processor #1 Pentium(tm) Pro APIC version 17
I/O APIC #2 Version 17 at 0xFEC00000.
Processors: 2
mapped APIC to ffffe000 (fee00000)
mapped IOAPIC to ffffd000 (fec00000)
Detected 447696347 Hz processor.
Console: colour VGA+ 80x25
Calibrating delay loop... 445.64 BogoMIPS
...
  8K byte-wide RAM 5:3 Rx:Tx split, autoselect/Autonegotiate interface.
  MII transceiver found at address 24, status 782d.
  Enabling bus-master transmits and whole-frame receives.
Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
nfsd_init: initialized fhcache, entries=256
...

Do the same thing, but also show the log level preceding each message:

py-crash> log -m
<4>Linux version 2.2.5-15smp (root@mclinux1) (gcc version egcs-2.91.66 19990
314/Linux (egcs-1.1.2 release)) #1 SMP Thu Aug 26 11:04:37 EDT 1999
<4>Intel MultiProcessor Specification v1.4
<4>    Virtual Wire compatibility mode.
<4>OEM ID: DELL     Product ID: WS 410       APIC at: 0xFEE00000
<4>Processor #0 Pentium(tm) Pro APIC version 17
<4>Processor #1 Pentium(tm) Pro APIC version 17
<4>I/O APIC #2 Version 17 at 0xFEC00000.
<4>Processors: 2
<4>mapped APIC to ffffe000 (fee00000)
<4>mapped IOAPIC to ffffd000 (fec00000)
<4>Detected 447696347 Hz processor.
<4>Console: colour VGA+ 80x25
<4>Calibrating delay loop... 445.64 BogoMIPS
...
<6>  8K byte-wide RAM 5:3 Rx:Tx split, autoselect/Autonegotiate interface.
<6>  MII transceiver found at address 24, status 782d.
<6>  Enabling bus-master transmits and whole-frame receives.
<6>Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
<7>nfsd_init: initialized fhcache, entries=256
...

On a system with the variable-length record format, and whose log_buf has been filled and wrapped around, display the log with timestamp data:

py-crash> log
[    0.467730] pci 0000:ff:02.0: [8086:2c10] type 00 class 0x060000
[    0.467749] pci 0000:ff:02.1: [8086:2c11] type 00 class 0x060000
[    0.467769] pci 0000:ff:02.4: [8086:2c14] type 00 class 0x060000
[    0.467788] pci 0000:ff:02.5: [8086:2c15] type 00 class 0x060000
[    0.467809] pci 0000:ff:03.0: [8086:2c18] type 00 class 0x060000
[    0.467828] pci 0000:ff:03.1: [8086:2c19] type 00 class 0x060000
...

Display the same message text as above, without the timestamp data:

py-crash> log -t
pci 0000:ff:02.0: [8086:2c10] type 00 class 0x060000
pci 0000:ff:02.1: [8086:2c11] type 00 class 0x060000
pci 0000:ff:02.4: [8086:2c14] type 00 class 0x060000
pci 0000:ff:02.5: [8086:2c15] type 00 class 0x060000
pci 0000:ff:03.0: [8086:2c18] type 00 class 0x060000
pci 0000:ff:03.1: [8086:2c19] type 00 class 0x060000
...

Display the same message text as above, with appended dictionary data:

py-crash> log -td
pci 0000:ff:02.0: [8086:2c10] type 00 class 0x060000
SUBSYSTEM=pci
DEVICE=+pci:0000:ff:02.0
pci 0000:ff:02.1: [8086:2c11] type 00 class 0x060000
SUBSYSTEM=pci
DEVICE=+pci:0000:ff:02.1
pci 0000:ff:02.4: [8086:2c14] type 00 class 0x060000
SUBSYSTEM=pci
DEVICE=+pci:0000:ff:02.4
pci 0000:ff:02.5: [8086:2c15] type 00 class 0x060000
SUBSYSTEM=pci
DEVICE=+pci:0000:ff:02.5
pci 0000:ff:03.0: [8086:2c18] type 00 class 0x060000
SUBSYSTEM=pci
DEVICE=+pci:0000:ff:03.0
pci 0000:ff:03.1: [8086:2c19] type 00 class 0x060000
SUBSYSTEM=pci
DEVICE=+pci:0000:ff:03.1
...