System and processes

The dmesg command

Shows the kernel messages since boot: detected hardware, disks, network and errors.

Syntax

dmesg

Most useful options

-TReadable dates instead of seconds since boot
-l nivelFilters by level (err, warn...)

Copy-ready examples

$ dmesgThe whole boot
$ dmesg | tail -n 20The latest from the kernel

You can try them in the browser terminal: it does not touch your computer.

Typical mistakes

  • Kernel messages are in English.
  • If a USB or a disk does not work, the clue usually shows up here.

Related commands

journalctlsystemctlpsuptime

FAQ

What does the number in brackets mean?

The seconds elapsed since the system booted.

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