On 2020-01-14 07:10, Mauricio Tavares wrote:
On Mon, Jan 13, 2020 at 5:46 PM Ed Greshko
<ed.greshko(a)greshko.com> wrote:
> On 2020-01-14 06:01, Mauricio Tavares wrote:
>> So I want to add a few options to the kernel (say iommu support). I
>> have been told before to avoid using grub2-mkconfig because it would
>> apply the changes to all currently available (to boot from) boot
>> kernels. Instead, I should edit just the latest kernel entry in the
>> grub.cfg file, adding the option to the line starting with linux16.
>> This way, if it went boink, all I had to do is reboot, pick another
>> kernel from the grub menu and off I went. And, it seems that every
>> future kernel upgrade would incorporate this change.
>>
>> Is that accurate or is there a cleaner way to do the same while still
>> leaving me the option to go back to the grub menu?
>>
> Do you wish to try out some options without make a permanent change?
>
> Assuming your using Fedora Workstation, which unlike other spins, doesn't present
the list of kernels to boot.
> You'd just hit the "escape" key when booting. Then you'd see the
list of kernels. Hit "e" to edit. Go to the
> linux line, add the parameters and then Ctrl-x to continue the boot.
>
> Those changes are temporary.
>
> If all works as you'd like, then you could make them permanent.
>
Thank you for your reply but it seems I failed to properly
explain myself. I want to ensure my changes only affect the latest
kernel (and future kernels) as listed in the grub menu. I was not
aware there is a version of fedora which would not list available
kernels; if there is I would rather not use such version. The fedora
version I use does provide me with a proper grub menu hence me
describing that in the problem statement.
When you escape into the menu you'll most likely see 3 (or 4 if there is a rescue)
kernel.
The one at the top is the most recent, default, kernel.
Your changes will only affect the kernel that you pick to edit, the most recent/default.
The changes will only be for the one boot.
If you boot again, the changes will have to be made again. That is what I meant by
"temporary".
This, is good for "testing" should things go bonkers. You can reboot, the
changes you made are gone.
And you can continue as normal.
I should have indicated that, in my experience, that was a good way to test things with
the least amount
of pain should things go wrong. Then, after testing, make things permanent.
--
The key to getting good answers is to ask good questions.