How to copy contents of console's scrollback buffer to a file?

bdantas · 2014-07-24 11:32:00

I already know about

cat /dev/vcs1 > /path/to/some_file

and

setterm -dump 1 -file /path/to/some_file

but these only work for what is actually on tty1's screen when the command is run (i.e., lines in the scrollback buffer do not get written to the file). I have "fbcon=scrollback:512" in grub2's kernel line, in case it matters.

(I am trying to recreate the old /var/log/boot but, since even in quiet mode grub2 prints [FAIL] and all the [OK] messages that follow, if the [FAIL] occurs early enough it scrolls off the screen. See here: https://bbs.archlinux.org/viewtopic.php … 1#p1439361)

EDIT: Link fixed. Thanks for the heads up, karol.

Last edited by bdantas (2014-07-24 20:31:46)

karol · 2014-07-24 11:45:29

Please fix the link, it should be https://bbs.archlinux.org/viewtopic.php … 1#p1439361

Last edited by karol (2014-07-24 11:49:39)

bdantas · 2014-07-30 13:25:52

Is it impossible to copy the contents of the scrollback buffer of a virtual console (e.g., tty1) to a file?

amanual · 2014-08-01 03:53:00

in theory you could dump the contents of the scrollback, this is the pointer to it https://git.kernel.org/cgit/linux/kerne … 6-rc7#n185
you could dump that before the console gets switched*, right before here: https://git.kernel.org/cgit/linux/kerne … 6-rc7#n846

* e.g. when X gets started and is about to get graphical

jasonwryan · 2014-08-01 04:47:52

bdantas wrote:

Is it impossible to copy the contents of the scrollback buffer of a virtual console (e.g., tty1) to a file?

No

karol · 2014-08-01 23:20:26

I use 'systemd.show_status=0' along with 'quiet' to keep systemd from printing stuff I don't need.

Isn't systemd's journal enough to figure out what went wrong?

bdantas · 2014-08-02 03:16:00

Yes, "sudo journalctl -b -p err" shows me exactly what went wrong, so I think there is no need to pursue this further.

karol · 2014-08-02 22:53:20

Please remember to mark the thread as solved https://bbs.archlinux.org/viewtopic.php?id=130309

bdantas · 2014-08-02 23:09:15

I favor that it isn't solved because what I asked is not possible. Fortunately, the journal obviates the need for a solution. Is it customary to mark as "solved" when a workaround is found?

Last edited by bdantas (2014-08-02 23:35:20)

karol · 2014-08-02 23:33:33

Ah, OK.

Have you tried to keep the messages in the tty and start X from another tty, if needed?
You can then copy the messages by hand.

bdantas · 2014-08-02 23:39:06

Exactly. Either that or, if X starts automatically in tty1 due to autologin enabled in DM, using "sudo journalctl -b -p err" to get equivalent information.

Arch Linux

#1 2014-07-24 11:32:00

How to copy contents of console's scrollback buffer to a file?

#2 2014-07-24 11:45:29

Re: How to copy contents of console's scrollback buffer to a file?

#3 2014-07-30 13:25:52

Re: How to copy contents of console's scrollback buffer to a file?

#4 2014-08-01 03:53:00

Re: How to copy contents of console's scrollback buffer to a file?

#5 2014-08-01 04:47:52

Re: How to copy contents of console's scrollback buffer to a file?

#6 2014-08-01 23:20:26

Re: How to copy contents of console's scrollback buffer to a file?

#7 2014-08-02 03:16:00

Re: How to copy contents of console's scrollback buffer to a file?

#8 2014-08-02 22:53:20

Re: How to copy contents of console's scrollback buffer to a file?

#9 2014-08-02 23:09:15

Re: How to copy contents of console's scrollback buffer to a file?

#10 2014-08-02 23:33:33

Re: How to copy contents of console's scrollback buffer to a file?

#11 2014-08-02 23:39:06

Re: How to copy contents of console's scrollback buffer to a file?

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