dmesg (for "diagnostic message") is a command on Unix-like operating systems that prints the message buffer of the kernel. This buffer contains a variety of important messages from those printed during boot to those used for debugging software. This information may also be stored to disk via a logging daemon, such as syslog.

Example output on a Linux system:

 Linux version 2.4.19 (root@darkstar) (gcc version 2.95.3 20010315 (release)) #1 Sat Aug 3 09:22:36 CEST 2002
 BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
 BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 000000000fff0000 (usable)
 BIOS-e820: 000000000fff0000 - 000000000fff3000 (ACPI NVS)
 BIOS-e820: 000000000fff3000 - 0000000010000000 (ACPI data)
 BIOS-e820: 00000000ffff0000 - 0000000100000000 (reserved)
 255MB LOWMEM available.
 Advanced speculative caching feature not present
 On node 0 totalpages: 65520
 zone(0): 4096 pages.
 zone(1): 61424 pages.
 zone(2): 0 pages.
 Kernel command line: BOOT_IMAGE=Linux ro root=801
 Local APIC disabled by BIOS -- reenabling.
 Found and enabled local APIC!
 Initializing CPU#0
 Detected 902.080 MHz processor.
 Console: colour dummy device 80x25
 Calibrating delay loop... 1795.68 BogoMIPS
 Memory: 256620k/262080k available (1310k kernel code, 5072k reserved, 410k data, 256k init, 0k highmem)
 Dentry cache hash table entries: 32768 (order: 6, 262144 bytes)
 Inode cache hash table entries: 16384 (order: 5, 131072 bytes)
 Mount-cache hash table entries: 4096 (order: 3, 32768 bytes)
 Buffer-cache hash table entries: 16384 (order: 4, 65536 bytes)
 Page-cache hash table entries: 65536 (order: 6, 262144 bytes)
 CPU: Before vendor init, caps: 0183fbff c1c7fbff 00000000, vendor = 2
 CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
 CPU: L2 Cache: 256K (64 bytes/line)
 CPU: After vendor init, caps: 0183fbff c1c7fbff 00000000 00000000
 Intel machine check architecture supported.
 Intel machine check reporting enabled on CPU#0.
 CPU: After generic, caps: 0183fbff c1c7fbff 00000000 00000000
 CPU: Common caps: 0183fbff c1c7fbff 00000000 00000000
 CPU: AMD Athlon(tm) processor stepping 02
 Enabling fast FPU save and restore... done.
 Checking 'hlt' instruction... OK.
 POSIX conformance testing by UNIFIX
 enabled ExtINT on CPU#0
 ESR value before enabling vector: 00000000
 ESR value after enabling vector: 00000000
 Using local APIC timer interrupts.
 calibrating APIC timer ...
 ..... CPU clock speed is 902.0632 MHz.
 ..... host bus clock speed is 200.4585 MHz.
 cpu: 0, clocks: 2004585, slice: 1002292
 CPU0
 PCI: PCI BIOS revision 2.10 entry at 0xfb4a0, last bus=1
 PCI: Using configuration type 1
 PCI: Probing PCI hardware
 Unknown bridge resource 0: assuming transparent
 PCI: Using IRQ router VIA * at 00:07.0
 PCI: Disabling Via external APIC routing
 Linux NET4.0 for Linux 2.4
 Based upon Swansea University Computer Society NET3.039
 Initializing RT netlink socket
 Starting kswapd
 Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
 vesafb: framebuffer at 0xd8000000, mapped to 0xd0800000, size 32768k
 vesafb: mode is 1024x768x16, linelength=2048, pages=0
 vesafb: protected mode interface info at c000:0ed1
 vesafb: scrolling: redraw
 vesafb: directcolor: size=0:5:6:5, shift=0:11:5:0
 Console: switching to colour frame buffer device 128x48
 fb0: VESA VGA frame buffer device
 pty: 256 Unix98 ptys configured
 Uniform Multi-Platform E-IDE driver Revision: 6.31
 ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
 VP_IDE: IDE controller on PCI bus 00 dev 39
 VP_IDE: chipset revision 16
 VP_IDE: not 100% native mode: will probe irqs later
 ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
 VP_IDE: VIA vt82c686a (rev 22) IDE UDMA66 controller on pci00:07.1
 ide0: BM-DMA at 0xd000-0xd007, BIOS settings: hda:DMA, hdb:pio
 ide1: BM-DMA at 0xd008-0xd00f, BIOS settings: hdc:pio, hdd:DMA
 hda: IBM-DTLA-307030, ATA DISK drive
 hdd: _NEC DV-5700B, ATAPI CD/DVD-ROM drive
 ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
 ide1 at 0x170-0x177,0x376 on irq 15
 hda: 60036480 sectors (30739 MB) w/1916KiB Cache, CHS=3737/255/63, UDMA(66)
 hdd: ATAPI 40X DVD-ROM drive, 256kB Cache, UDMA(33)
 Uniform CD-ROM driver Revision: 3.12
 Partition check:
 hda: hda1 hda2 < hda5 hda6 >
 Floppy drive(s): fd0 is 1.44M
 FDC 0 is a post-1991 82077
 eepro100.c:v1.09j-t 9/29/99 Donald Becker http://www.scyld.com/network/eepro100.html
 eepro100.c: $Revision: 1.36 $ 2000/11/17 Modified by Andrey V. Savochkin  and others
 PCI: Found IRQ 10 for device 00:0d.0
 PCI: Sharing IRQ 10 with 00:07.2
 PCI: Sharing IRQ 10 with 00:07.3
 PCI: Sharing IRQ 10 with 00:0b.0
 eth0: Intel Corp. 82557/8/9 Pro 100, 00:A0:C9:8E:27:FA, IRQ 10.
 Receiver lock-up bug exists -- enabling work-around.
 Board assembly 668081-004, Physical connectors present: RJ45
 Primary interface chip i82555 PHY #1.
 General self-test: passed.
 Serial sub-system self-test: passed.
 Internal registers self-test: passed.
 ROM checksum self-test: passed (0x3c15c8f1).
 Receiver lock-up workaround activated.
 Linux agpgart interface v0.99 (c) Jeff Hartmann
 agpgart: Maximum main memory to use for agp memory: 203M
 agpgart: Detected Via Apollo Pro KT133 chipset
 agpgart: AGP aperture is 128M @ 0xd0000000
 SCSI subsystem driver Revision: 1.00
 PCI: Found IRQ 11 for device 00:09.0
 scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.8
 
 aic7880: Single Channel A, SCSI Id=7, 16/253 SCBs
 (scsi0:A:0): 10.000MB/s transfers (10.000MHz, offset 15)
 Vendor: FUJITSU Model: M2954S-512 Rev: 0155
 Type: Direct-Access ANSI SCSI revision: 02
 scsi0:A:0:0: Tagged Queuing enabled. Depth 253
 spurious 8259A interrupt: IRQ7.
 Attached scsi disk sda at scsi0, channel 0, id 0, lun 0
 SCSI device sda: 8498506 512-byte hdwr sectors (4351 MB)
 sda: sda1 sda2 sda3
 Creative EMU10K1 PCI Audio Driver, version 0.19, 09:23:56 Aug 3 2002
 PCI: Found IRQ 10 for device 00:0b.0
 PCI: Sharing IRQ 10 with 00:07.2
 PCI: Sharing IRQ 10 with 00:07.3
 PCI: Sharing IRQ 10 with 00:0d.0
 emu10k1: EMU10K1 rev 8 model 0x8027 found, IO at 0xe000-0xe01f, IRQ 10
 ac97_codec: AC97 codec, id: 0x5452:0x4123 (TriTech TR A5)
 NET4: Linux TCP/IP 1.0 for NET4.0
 IP Protocols: ICMP, UDP, TCP, IGMP
 IP: routing cache hash table of 2048 buckets, 16Kbytes
 TCP: Hash tables configured (established 16384 bind 16384)
 ip_conntrack (2047 buckets, 16376 max)
 ip_tables: (C) 2000-2002 Netfilter core team
 NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
 NET4: Linux IPX 0.47 for NET4.0
 IPX Portions Copyright (c) 1995 Caldera, Inc.
 IPX Portions Copyright (c) 2000, 2001 Conectiva, Inc.
 VFS: Mounted root (ext2 filesystem) readonly.
 Freeing unused kernel memory: 256k freed
 eth0: 0 multicast blocks dropped.
 

See also

• uname
• List of Unix programs

External link

• manpage

Unix software