Grub 2 Basics

[ranch hand]

The entry that is in /boot/grub/grub.cfg is an easy copy/paste.

I would encourage another entry;

menuentry "Lxde on sda8" {
    set root=(hd0,8)
        linux /vmlinuz root=/dev/sda8 ro quiet splash
        initrd /initrd.img
}

It boots to the newest kernel on the defined partition. Never needs updated.

[meierfra.]

"Costum"

Thanks. I fixed those.

but is there a way to "search" all of your HowTo's on SourceForge.

Click on "Main Page" in the left navigation panel in any of my howto's
Or just click here:

https://sourceforge.net/apps/mediawi...itle=Main_Page

I started about a week ago writing those Howto. It's a Wicki. So anybody can add a new HowTo or fix mistakes in the current HowTos. In the long run I would like to have a HowTo for each of the usual boot problems we run into in the forums. And, if I find time, I'll try to teach the Boot Info Script to detect those problem and, for every problem detected, insert a link in "RESULTS.txt" to the correspond Howto in the Boot Info Script Wicki.

sudo chmod -x /etc/grub.d/30_os-prober

This removes the "executable" bit from "30_os-prober"
You can see the effect by running

ls -l /etc/grub.d/30_os-prober

before and after.

To reverse it

sudo chmod +x /etc/grub.d/30_os-prober

That would be the info I wanted to use for the "set root" and "search" settings

Yes.

linux /vmlinuz root=/dev/sda8 ro quiet splash
 initrd /initrd.img

It boots to the newest kernel on the defined partition. Never needs updated.

My HowTo says the same thing.

[kansasnoob]

linux /vmlinuz root=/dev/sda8 ro quiet splash
initrd /initrd.img

Both of you taught me a lot today

I have to say it's great to learn all this.

[Burillo]

can i hide the partition in GRUB 2? like before booting

[peter b]

for anyone interested re #226 - #230 --no-floppy option ; answer from

sh:grub> help search
Usage: search [-f|-l|-u|-s|-n] NAME
Search devices by file, filesystem label or filesystem UUID. If --set is specified, the first device found is set to a variable. If no variable name is specified, "root" is used.

-f, --file search devices by a file
-l, --label search devices by a filesystem label
-u, --fs-uuid search devices by a filesystem UUID
-s, --set=VAR set a variable to the first device found
-n, --no-floppy do not probe any floppy drive
-h, --help display this help and exit
--usage display the usage of this command and exit

ex

sh:grub> search -f /boot/grub/grub.cfg
host hd0,8 hd2,1
sh:grub>

@drs305

didn't try yet removing --no-floppy from script and do a new grub.cfg I'll do it when time permits and keep you posted.

[drs305]

can i hide the partition in GRUB 2? like before booting

You will have to be more specific. What partition are you trying to hide? There are various ways: disabling certain scripts in /etc/default.d or by modifying scripts.

If you want to hide the Windows Recovery partition, you can review the section in Section 2F of Grub 2 Title Tweaks

[Burillo]

You will have to be more specific. What partition are you trying to hide? There are various ways: disabling certain scripts in /etc/default.d or by modifying scripts.

If you want to hide the Windows Recovery partition, you can review the section in Section 2F of Grub 2 Title Tweaks

i am trying to hide one windows partition from another windows partition at boot time. the reason behind this is that these two partitions are cloned (i.e. have the same OS and same partition ID) and in order to prevent these two OS's from knowing about each other i want to hide one partition at boot time.

[R3M3]

13. Reinstalling GRUB 2 from LiveCD
...
Substitute the correct device - sda, sdb, etc. Do ''not'' specify a partition number.

This is frustrating - "correct device" FOR WHAT!

Is this the device on which your file system root is located on?
Is the device you want the MBR on?
Something else?

Specifying that something needs to be "correct" without giving anyone a way of knowing what "correct" should be is simply infuriating.

P.S. What's up with the irony quotes around not?

[drs305]

This is frustrating - "correct device" FOR WHAT!

Is this the device on which your file system root is located on?
Is the device you want the MBR on?
Something else?

The correct device is the one your Ubuntu installation is on.

Specifying that something needs to be "correct" without giving anyone a way of knowing what "correct" should be is simply infuriating.

Sorry it wasn't clear to you. The first paragraph of the section asks readers to refer to the community doc for elaboration. I will reword the section.

P.S. What's up with the irony quotes around not?

Nothing. (Insert irony here).

[R3M3]

The correct device is the one your Ubuntu installation is on.

And if your Ubuntu installation is on multiple partitions spread over multiple hard drives? (e.g. / on one, /usr on another, /home on a third, etc.) Which one is it then?

At any rate, if it's the location of a *filesystem* I don't understand why you specify the drive rather than the partition. Specifying just the drive would make more sense if it's the location of the MBR you're booting from, rather than the location of the Ubuntu filesystem. The distinction is important if you have a situation where the booted drive isn't your Ubuntu one. (Say you have /hda given over entirely to Windows, and are installing Ubuntu on a separate harddrive.)

Sorry it wasn't clear to you.

That's okay. I was just increasingly frustrated after encountering the same vague statement in a number of places. Nothing against your version in particular - it's just the only one I could vent on.

Edit Addition:

Careful reading of the community docs now seems to indicate that the device specification is the location of the booted drive (location of the MBR), rather than the location of the Ubuntu file system.

Run the grub-install command as described below. This will reinstall the GRUB 2 files on the mounted partition to the proper location and to the MBR of the designated device.

sudo grub-install --root-directory=/mnt/ /dev/sdX

I'd interpret that as meaning if you had the BIOS set to boot /sda, but had installed the Ubuntu filesystem on /sdb1 (because e.g. /sda1 is your Windows drive), you would specify /dev/sda as the device.

(I swear it wasn't that clear when I read it earlier. - Not that I'm 100% sure that's what it means.)