Re: Where are startup messages logged?

From: Moe Trin (ibuprofin_at_painkiller.example.tld)
Date: 08/03/05


Date: Tue, 02 Aug 2005 20:15:17 -0500

In the Usenet newsgroup linux.redhat, in article
<11et1nvkfkr4r8c@corp.supernews.com>, exotic-scales wrote:

>I'd like to be able to inspect some messages that went by too fast to
>register. Could someone tell me where the log is (Red Hat 9). Thanks.

Depends. Near the end of the boot process, the ring buffer is dumped
to a file called /var/log/dmesg. There are no timestamps, and this is
only part of the data that is normally scrolled to the screen. You can
also inspect the ring buffer afterwards, but as the name implies this
is a RING, and only the last (typically) 4096 bytes are there.

Some information is also sent to /var/log/messages.

Error messages (stderr) are not saved anywhere. To see them after the
fact, you need to be booting into text mode (not the GUI). On the
first virtual console (Alt+F1) before ANY keyboard input is attempted
(that is, before login, or any other action on the keyboard), you can
try pressing the Shift and PgUp keys to scroll back through the screen
buffer. This ONLY works in a raw text mode, only in the first virtual
terminal, and only as long as the screen buffer length isn't exceeded.

Another technique that might work is a "remote console" (see the
Remote-Serial-Console-HOWTO), and recording the output remotely. This
requires an additional computer (to act as the remote terminal) or
a very d4mn fast serial printer.

        Old guy