Boot Logs

Boot logs record kernel initialization and early system events.

Kernel Initialization Messages

Input:

dmesg | less

Output:

[    0.000000] Linux version 6.6.0 (gcc version 13.2.0)
[    1.234567] usb 1-3: new high-speed USB device number 2 using xhci_hcd

Kernel messages showing hardware detection and subsystem initialization.

References:

• https://man7.org/linux/man-pages/man1/dmesg.1.html

systemd Boot Journal

Input:

journalctl -b

Output:

Nov 18 10:01:22 host systemd[1]: Starting udev Kernel Device Manager...
Nov 18 10:01:23 host NetworkManager[612]: <info> device added

Aggregated logs for the current boot from systemd’s journal.

References:

• https://man7.org/linux/man-pages/man1/journalctl.1.html

Previous Boot Errors

Input:

journalctl -b -1 -p err

Output:

Nov 18 09:55:02 host kernel: ata1: COMRESET failed

Shows error-level logs from the previous boot for troubleshooting.

References:

• https://man7.org/linux/man-pages/man1/journalctl.1.html

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