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Kernel Log Insights with dmesg


Send custom messages to dmesg output

Option Description
<3> err
<4> warning
<5> notice
<6> info
<7> debug
echo "<6>Hello from userspace" | sudo tee /dev/kmsg >/dev/null

Dump all data with level warning and errors

dmesg --level=err,warn

Dump all data for all avilable options

dmesg --level=emerg,alert,crit,err,warn,notice,info,debug

Dump all data with level lower then warning

dmesg --level=+warn

Dump kernel log

dmesg

Clear kernel log

dmesg -c

Read kernel log in realtime

dmesg -wxT

With human-readable timestamp

dmesg --time-format --syslog 

With human-readable timestamp

dmesg -T 
dmesg --time-format iso
dmesg --time-format ctime

dmesg with colored human-readable dates

dmesg -T|sed -e 's|\(^.*'`date +%Y`']\)\(.*\)|\x1b[0;34m\1\x1b[0m - \2|g'

Get cpu info from dmesg

dmesg | grep cpu