Ubuntu – No more boot logging since 16.04


I noticed that my /var/log/boot.log file has date 2016-04-22, last time I booted in 15.10. Where are Xenial boot.log files located?

Best Answer

I was going through some bug reports and noticed in this one: https://bugs.launchpad.net/ubuntu/+source/ubuntu-gnome-default-settings/+bug/1536771 that Plymouth is actually writing to boot.log.

If you look at https://launchpadlibrarian.net/257898272/plymouth-debug.log and search in your browser for 'boot.log' you get the following lines:

[main.c:821] on_system_initialized:system now initialized, opening log 
[main.c:742] get_log_file_for_state:returning log file '/var/log/boot.log'
[main.c:805] prepare_logging:opening log '/var/log/boot.log'

I have no understanding of how the internals of Plymouth work, but since it is responsible for the splash screen that shows up before the login screen, I can only assume that if there is no splash screen (black screen) before getting to the login screen, the file is not modified. If you do have a splash screen showing before the login screen, the boot process output is redirected to the boot.log file.

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