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My Arch install throws up a red error when booting but I can't see what it says because it flies by so quickly during loading. Where is the boot log? Would it be somewhere in /var/log? or maybe in /boot?

Would much rather see the log text file than the scroll lock trick.

2 Answers 2

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The kernel does not have a filesystem to write to during most of boot, so if the boot failed, you may be out of luck. However, it does keep a log in memory (including what you see on the console) and once it does have a rw fs, that stuff is dumped into /var/log/syslog.

You can also view the kernel log starting from the beginning with dmesg (probably you want to use dmesg | less).

However, I don't think the kernel uses colored emphasis (in any case, the color itself won't be in a log), implying this is a system service. Some of those also start before a rw filesystem is available, and if that's the case, there may be no record of the message at all. Otherwise their stuff should also be in /var/log/syslog.

You can also try SCROLL LOCK, or ctrl-S (pause) ctrl-Q (continue) during boot. There's also a "boot_delay" parameter that can be put on the kernel command-line (e.g. in grub.conf).

From src/Documentation/kernel-parameters.txt:

boot_delay =  Milliseconds to delay each printk during boot.
              Values larger than 10 seconds (10000) are changed to
              no delay (0).
              Format: integer

Hopefully at least one of these works for you.

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  • Yes! This absolutely worked. You were right about the coloring and service. It was a display manager service that was set to run, but I must have deleted the file. Thank you!
    – c-o-d
    Commented Aug 17, 2013 at 15:42
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You can access all logs from your current boot with:

journalctl -b

In case you want a color output and saved to html format you need ccat installed:

journalctl -b | ccat --html > boot_log.html

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