Grub

Resources

• http://www.gnu.org/software/grub/
• https://help.ubuntu.com/community/Grub2
• https://wiki.gentoo.org/wiki/GRUB2
• https://www.dedoimedo.com/computers/grub-2.html

Repair/update Grub2

• Repair Grub2
• How to Update Grub on Ubuntu and Other Linux Distributions. Good instruction. Two disks; each with its own Linux distribution. The second disk won't install Grub. So the Linux on the 1st disk needs to update its grub so it can see the Linux on the 2nd disk.

Show the grub2 screen

To show the grub2 screen, run 'sudo nano /etc/default/grub' and comment out the line GRUB_HIDDEN_TIMEOUT=0 and change the line GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to GRUB_CMDLINE_LINUX_DEFAULT="". Remember to run 'sudo update-grub' after any change to grub.

Add a splash image

Follow the instruction at https://help.ubuntu.com/community/Grub2/Displays. Note that Grub2 will search the image based on some priority and there are also some minor requirements on the images. To test

sudo apt-get install grub2-splashimages
sudo cp /usr/share/images/grub/Moraine_Lake_17092005.tga /boot/grub/
sudo update-grub

How do I set the grub timeout and the grub default boot entry?

https://askubuntu.com/questions/148095/how-do-i-set-the-grub-timeout-and-the-grub-default-boot-entry

1. gksudo gedit /etc/default/grub
2. Change as you like. Save and closed the file.
   • You can change the default from 0 to any number
   • You can change the "hidden timeout" (no menu)
   • You can force the grub menu to show by commenting out the two GRUB_HIDDEN lines with a # at the beginning of the line
   • set the grub menu timeout (default is 10 seconds)
3. sudo update-grub
4. Reboot

Boot into command line

http://www.linuxandubuntu.com/home/how-to-boot-into-linux-command-line

1. Highlight the first item (default) and press 'e' in the GRUB menu
2. Navigate to the line that starts with ‘linux’, change the runlevel to 3 (at the end of the line). Level 3 means multi-user, command-line only system
3. Press Ctrl+x or F10 to boot into

To switch back to GUI, type sudo init 5. Level 5 is the default.

Grub Customizer - GUI program

How To Change The GRUB Boot Order Or Default Boot Entry In Ubuntu, Linux Mint, Debian, Or Fedora With Grub Customizer