Tag: grub

Ubuntu grub timeout warning on update

Shortly updating to Ubuntu Trusty (14.04), I noticed the following warning on my console during updates. I finally got around to looking into it deeper and found that many users have seen this too.

Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported.

If you edit the ‘grub’ file, you can comment out the GRUB_HIDDEN_TIMEOUT line by adding a hash in front of it.

sudo vi /etc/default/grub

Verify that the error is fixed by executing the following:

sudo update-grub

If you are interested, you can also go and look at the updated ‘grub’ file at

/boot/grub/grub.cfg

NOTE: I’d also seen that the following command could be used, but it was of no use in my testing.

/usr/share/grub/default/grub

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Ubuntu fixing screen backlight brightness toggle

For quite some time, my primary Ubuntu laptop has had a problem with the keyboard keys used to adjust the screen brightness. This had been an annoyance on some of my travels where I’d wanted to extend battery life, as well as when I prefer to work in a darker space. I knew that it had to be a software driver issue of some sort, as it worked in my sometimes used dual boot Windows environment, but I’d never been bothered enough to look for a solution.

Truth is, it only took a minute or two to fix this!

  1. Modify the grub boot loader.
    sudo vi /etc/default/grub
  2. Change the line from:
    GRUB_CMDLINE_LINUX=""
    to
    GRUB_CMDLINE_LINUX="quiet splash acpi_osi=Linux acpi_backlight=vendor"
  3. Update the loader:
    sudo update-grub
  4. Reboot and you should be good to go!

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Remove old Ubuntu kernels

If you update your Ubuntu kernel frequently, eventually you will come to the realization that it is taking a lot of space to keep the old versions around on disk. Another annoyance is that your Grub loader will show a very long list. Sure, you can keep them around forever, should you need to recover them, but for most people it’s safe to remove them. You can manually select and remove the packages in Synaptic, but the easiest way I’ve found is to sun the following script instead. It will remove all old kernel version (except the current one!):

dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d' | xargs sudo apt-get -y purge

Occasionally, you might also want to follow that with the following to clean up other artifacts too…
sudo apt-get autoremove

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