Change boot kernel linux

With the command above and its output, you can see the code corresponding to each OS version, which gives you the number to use in the /etc/default/grub file.

Instead of editing the /etc/default/grub file by hand, I suggest using sed . In the following command, replace X with the appropriate number as determined above:

sudo sed -i 's/GRUB_DEFAULT=0/GRUB_DEFAULT=X/g' /etc/default/grub; sudo update-grub

This isn't an answer. It reads like a comment. An answer should say, "This is how to set the default entry in GRUB", not "let me make an addendum to another answer". You can easily edit this into a proper answer, but it might be smarter to just leave a comment on jkt123's answer about using awk instead of grep.

I think this answer does improve signifcantly on the answer proposing grep, if you compare the output of the two, the awk output is much easier to use (includes number, easier to read). But, the introduction should probably be re-written so this answer stands alone, and doesn't read like a comment to the grep answer.

I would love to see a real helper to do this thing and not just scripts. I tried this solution and I broke my boot and, since I don't have physical access to the machine, I couldn't boot it anymore. On Ubuntu 20 the default option is GRUB_DEFAULT="1>0" , and not just a number. I wanted to boot option 5 (from this awk cmd), but 1>5 broke it since apparently the second menu is a 0-indexed menu. Still looking for a reliable remote solution to set default kernel.

In order to do it with a GUI, I use Grub Customizer (I'm in Mint and have installed it like this.).

The idea is to keep the Advanced options in the grub list in case the default list is changed within Grub Customizer.

Then, under General settings select the default entry: previous booted entry.

Then, reboot, and during boot select the "Advanced options" entry in the grub list:

and select the desired kernel

On the next reboot, the "Advanced options" item will be the one selected by default in the grub list and the last selected kernel from under there will be booted (without opening the full list of kernels).

In case Windows is used, or other option in the grub list, remember to re-do the previous procedure.

jkt123's answer will work for most distributions, I guess. However, for Arch Linux it didn't work, at least not with the packages I have available.

The indices you can set with grub-set-default only correspond to the main menu entries. The kernel options are however in a submenu. So either you move the kernel entry out of the submenu into the main menu or you put the entry on top of the submenu list and select the submenu.

My GRUB Menu

To be able to boot Kernel 2, you have to either swap it with Kernel 1 or you put it outside the submenu on the same level as Arch Linux or Windows. And then set the default number to one of the main menu indices. For example, in the menu above "0" boots "Arch Linux" and "1" boots Kernel 1.

To change the hierarchy and swap, open /boot/grub/grub.cfg and move the entry you wish to move. An entry could look like this

menuentry 'ENTRY NAME' . some code . > 

Then you need to apply your changes. In my case with grub-mkconfig . But this might vary from system to system.

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How to change the kernel to boot in GRUB?

I have kernel 4.4.0-66-generic-tuxonice and would like to change it to another one 4.4.0-66-generic. How can I change the entries in the grub config file in order to do this? I have:

I believe we can select a specific kernel by specifying its name also? I have no idea of how to do that though. The reason is that 4.4.0-66-generic seems to do hibernation better than the TuxOnIce but it requests the TuxOnIce files be installed.

@ElderGeek +1 to close as "unclear what you're asking". The question has a good answer which seems solve the original problem. But the question is still horribly hard to understand. I thus vote to close. We can re-open the question once it has been updated.

wanted to make sure that Grub-Customiser would work and was hoping to find out the name of the kernel in the terminal and enter it into the /etc/default/grub to make it the default one

@MadMike Seems clear to me. OP wanted to change which kernel is booting by default in GRUB. Perhaps since I've spent an inordinate amount of time monkeying with GRUB recently? I wouldn't be at all surprised if there are questions that are baffling to me that are clear as glass to you. We are all the products of our experiences after all. Good thing there are so many of us on the team. All that aside, if the community agrees with your assessment it will be closed. I for one thought it was about as straightforward as "Would you sugar or artificial sweetener in your coffee?" 😉

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SET GRUB_DEFAULT=0 is for all intents and purposes an index number indicating the first entry.

If your intent is to modify an existing entry to use a different kernel you can edit /etc/boot/grub/grub.cfg find the appropriate line and adjust for example:

linux /boot/vmlinuz-3.13.0-86-generic root=UUID=03a31723-1f61-4bae-ae5d-403cd35d0adc (and etc) 

and change the vmlinuz-x.xx-x-xx-blahblah bit to point to your existing preferred kernel.

The above is a bit of a hack though and might break at the next update. (I've done such things on flash drives booting ISO's that never change and never update grub on them.)

If your intent is simply to select a kernel already on the grub menu as default, I think you'll find the powerful grub customizer by Daniel Richter quite useful.

You can right click on a kernel entry in the list configuration and choose to move it up or down or edit it.

On the General Settings Tab, You can easily select and set the default entry by name from the list of predefined entries (as you indicated in your question.) See the image below for an example:

Save your changes and reboot and enjoy your new default boot entry.

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