GRUB config and validation

To check the GRUB settings on a Linux system, you can use the cat command to view the contents of the /etc/default/grub file. This file contains the default GRUB settings for your system.

Here's how to check the GRUB settings:

Open a terminal window on your Linux system.

Type the following command and press Enter:

cat /etc/default/grub

1. The cat command will display the contents of the /etc/default/grub file, which contains the default GRUB settings. You can look for settings such as GRUB_DEFAULT, GRUB_TIMEOUT, and GRUB_CMDLINE_LINUX to see the current values.

Here's an example output from the cat command:

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
#   info -f grub -n 'Simple configuration'

GRUB_DEFAULT=0
GRUB_TIMEOUT=5
GRUB_TIMEOUT_STYLE=menu
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

In this example, the GRUB_DEFAULT setting is set to 0, which means that the first entry in the GRUB menu will be selected by default. The GRUB_TIMEOUT setting is set to 5, which means that the GRUB menu will be displayed for 5 seconds before the default entry is selected. The GRUB_TIMEOUT_STYLE setting is set to menu, which means that the GRUB menu will always be displayed. The GRUB_CMDLINE_LINUX_DEFAULT setting is set to "quiet splash", which adds the quiet and splash options to the kernel command line.

After making any changes to the /etc/default/grub file, you should run the update-grub command to update the GRUB configuration file (/boot/grub/grub.cfg) with your changes:

sudo update-grub

This will update the GRUB settings with the changes you made in the /etc/default/grub file.