How to Change Kernel Boot Parameters in GRUB on Linux.md

How to Change Kernel Boot Parameters in GRUB on Linux

When troubleshooting or customizing your Linux system, you may need to adjust kernel boot parameters. One common case is switching from the default quiet boot to a verbose boot, which displays detailed system messages during startup. This guide explains how to make this change by editing the GRUB configuration.

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Step 1: Open the GRUB Configuration File

The GRUB settings are stored in /etc/default/grub. Open this file with a text editor such as nano or vim using root privileges:

sudo nano /etc/default/grub

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Step 2: Modify the Kernel Command Line

Inside the file, look for the line starting with GRUB_CMDLINE_LINUX. By default, it may look like this:

GRUB_CMDLINE_LINUX="... rhgb quiet"

The options rhgb and quiet hide most boot messages. To switch to verbose mode, replace them with verbose:

GRUB_CMDLINE_LINUX="... verbose"

Save the file and exit the editor.

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Step 3: Regenerate the GRUB Configuration

To apply the changes, regenerate the GRUB configuration. Run:

sudo grub2-mkconfig -o /etc/grub2.cfg --update-bls-cmdline

This updates the bootloader with your new kernel parameters.

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Step 4: Reboot and Verify

Finally, reboot your system:

sudo reboot

You should now see detailed system messages during startup instead of the quiet splash screen.

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✅ Summary: By editing /etc/default/grub and regenerating the GRUB configuration, you can easily switch from a quiet boot to verbose mode, which is helpful for diagnosing issues or monitoring system activity during boot.