Linux command (All): demsg command-Displays boot information

demsg command

Function description

The demsg command is used to display the boot information, the kernel stores the power-on information in the system buffer (ring buffer), can be viewed with the DMESG command after power-on, or the DMESG file in the/var/log/directory. Use the following:

DMESG [Options]

Command parameters

option
-s
-n	Set the level of logging information

Information about the kernel buffers is useful for diagnostic systems. Can be used with grep when viewing.

Example

     use tail to see the last 10 messages

[Email protected] ~]# DMESG | tail [14.173511] Ebtables v2.0 registered [14.211151] Bridge firewalling registered [15.018274] Ipv6:addrconf (NETDEV_UP): Eno16777736:link is isn't ready [15.023187] e1000:eno16777736 NIC Link is up to $ Mbps full Duplex, Flow Control:none [15.027562] Ipv6:addrconf (NETDEV_UP): Eno16777736:link is isn't ready [15.027571] Ipv6:addrconf (netdev_change): Eno16777736:link becomes ready [73937.594566] e1000:eno16777736 NIC Link is down [74082.150628] e1000:eno16777736 NIC Link is up to $ Mbps full Duplex, Flow Control:none [74082.153014] Ipv6:addrconf (netdev_change): Eno16777736:link becomes ready [102547.555629] perf interrupt took too long (2547 > 2500), lowering kernel.perf_event_max_sample_rate to 50000

Use grep to view information about network card devices

[email protected] ~]# DMESG | grep eno16 [2.834942] systemd-udevd[497]: Renamed network interface eth0 to eno16777736 [15.018274] Ipv6:addrconf (NETDEV_UP): Eno16777736:link is isn't ready [15.023187] e1000:eno16777736 NIC Link is up to $ Mbps full Duplex, Flow Control:none [15.027562] Ipv6:addrconf (NETDEV_UP): Eno16777736:link is isn't ready [15.027571] Ipv6:addrconf (netdev_change): Eno16777736:link becomes ready [73937.594566] e1000:eno16777736 NIC Link is down [74082.150628] e1000:eno16777736 NIC Link is up to $ Mbps full Duplex, Flow Control:none [74082.153014] Ipv6:addrconf (netdev_change): Eno16777736:link becomes ready

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Linux command (All): demsg command-Displays boot information