How to write kernel log directly to a file without user action?

10110111 · 04-23-2009, 01:29 PM

I have some crashes on Easy Peasy resume from standby after installing some package updates, these crashes logs are hard to copy from screen to paper by hand, and if i try to do this, the screen gets blank by power management (yes, surprisingly, this does work even after a crash).
How can i make kernel log appear not on the console, but in a file instead, and have this file 'sync'ed after each new line is written?

irishbitte · 04-23-2009, 01:59 PM

I would think something like this:

Code:

locate log | grep kernel

will show you that the kernel log may already be stored in /var/log/kernel.log or somewhere like that.

10110111 · 04-23-2009, 02:14 PM

Yes, there exists /var/log/kern.log, but there's no its backup, so it's overwritten after startup, while i need the log from previous, crashed, session.

irishbitte · 04-23-2009, 07:46 PM

Ok, here's an idea. When your system crashes:
1. reboot it using a liveCD,
2. mount the hard disk of the crashed system,
3. copy the kern.log file.

irishbitte · 04-23-2009, 07:47 PM

Another idea, dunno if it'll work for you:
http://www.faqs.org/docs/Linux-HOWTO...ash-HOWTO.html

syg00 · 04-23-2009, 08:29 PM

Sounds like your syslog or logrotate needs some configuring.
In _really_ dire circumstances, you could force a sync to disk using the magic sysrq, but you shouldn't be that bad. If the power management is still running, syslog should be.

Try a liveCD as suggested.