Unix and Linux Stack Exchange
Unix and Linux Stack Exchange

Questions tagged [grub]

This tag is ambiguous: use grub2 or grub-legacy as appropriate.

GNU GRUB (GRand Unified Bootloader) is a bootloader. It was originally intended as a common bootloader for various new operating systems conforming to the multiboot specification. Nowadays, many Linux distributions have adopted GRUB as their default bootloader.

There are two major versions of GRUB, with incompatible configuration files:

  • GRUB1, now known as GRUB Legacy, with version numbers up to 0.97;
  • GRUB2, with version numbers 1.90 and above.

Frequently Asked Questions:

External links

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Set the default kernel in GRUB

How can I pick which kernel GRUB 2 should load by default? I recently installed a Linux real-time kernel and now it loads by default. I'd like to load the regular one by default. So far I only managed to pick the default OS... and for some reason…
TomTom
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What is the equivalent of 'update-grub' for RHEL, Fedora, and CentOS systems?

In Ubuntu (and I guess in Debian too) there is a system script named update-grub which automatically executes grub-mkconfig -o with the correct path for the GRUB configuration file. Is there a similar command for Red Hat-based distributions? If not,…
pqnet
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How to start a windows partition from the Grub command line

I have Windows 10 HOME installed on my system. After I installed Windows 10 HOME, I installed Ubuntu 14.04 LTS on a separate partition so that I could dual boot. I removed Ubuntu 14.04 LTS by deleting the partition it was installed on. Now I am…
ANKIT SAINI
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Cannot find EFI directory: issue with grub-install

I was trying to rescue GRUB in Linux. I was able to login in the OS following this tutorial: https://www.lisenet.com/2014/grub2-rescue-mode-error-unknown-filesystem/ I have to upgrade GRUB to fix the problem. However, when I run grub-install, I get…
krishnakant
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How to switch arch linux to lts kernel?

I'm running a headless server installation of arch linux. The high rate of kernel upgrades caused me some maintainance headache and I therefore wish to switch to the lts kernel. I already installed the linux-lts and linux-lts-headers packages. Now,…
q9f
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Boot windows from grub rescue command prompt

Previously I had installed the Ubuntu 10.04 and Windows 7. Now I logged on to Windows, opened the partition editor and deleted the volume containing the Ubuntu - I thought it will delete the Ubuntu and it might help me install another OS - and I…
Karthi prime
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2 answers

A new version of configuration file /etc/default/grub is available, but the version installed currently has been locally modified

I am using 3.2.0-4-amd64 #1 SMP Debian 3.2.46-1 x86_64 GNU/Linux Debian GNU/Linux 7.1 (wheezy) Release: 7.1. I typed "sudo apt-get upgrade" and hoped for the best (I updated all my packages just before doing that with "sudo ap-get update"). I am…
Perlnika
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GRUB_CMDLINE_LINUX_DEFAULT vs GRUB_CMDLINE_LINUX

What is the difference between these two options in /boot/default/grub GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX=""
Evan Carroll
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What do the kernel parameters acpi_osi=linux and acpi_backlight=vendor do?

I had troubles with the screen brightness control in my laptop and I fixed it by adding the acpi_osi=linux and acpi_backlight=vendorparameters to the filegrub.cfg. I'd like to know what these parameters mean and why they work.
user91655
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"EFI\boot\bootx64.efi" vs "EFI\ubuntu\grubx64.efi" vs "/boot/grub/x86_64-efi/grub.efi" vs "C:\Windows\Boot\EFI\*"

I have installed Ubuntu 19 64bit alongside Windows 10 64bit and I found that I have 3 different EFI files in different locations: EFI\boot\bootx64.efi EFI\ubuntu\grubx64.efi /boot/grub/x86_64-efi/grub.efi What are the differences between these…
Yousha Aleayoub
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5 answers

How to stop update-grub from scanning all drives?

Every time update-grub is run all hard drives are scanned. Each drives that is in standby state will spin up to go idle. This is a waste of energy. We use update-grub version 1.98: # update-grub -v grub-mkconfig (GRUB)…
Pro Backup
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How does the grub efi loader find the correct grub.cfg and boot directory?

As I understand it, the uefi bios loads grub.efi from the efi partition. This now loads a bunch of grub modules and the configuration file from the /boot directory. But how does grub find the correct device in which the boot partition resides? In…
user128063
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How do I change the GRUB boot configuration from within Windows?

I currently dual boot Windows 7 and Fedora 14, using GRUB, with Windows 7 as my default. I know that from Fedora, I can set GRUB to boot into Fedora, overriding the default, on the next reboot. Is there a way to do this from Windows? That is, can I…
Jimmy Sawczuk
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Laptop boots directly to Ubuntu, can't access BIOS or Boot menu anymore

I'm running Laptop with single OS: UbuntuMATE 15.04 Beta1 64bit on Toshiba laptop Core i3. After burning "Elementary OS" on a live USB drive using UNetbootin, what happened is: -After reboot, laptop directly shows UbuntuMATE boot screen, doesn't…
Kamal Rais Al-Shishani
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Rotate console on startup (Debian)

I want to rotate my console (not X Server) by 90 degrees (clockwise). The following seems to work for me: echo 1 > /sys/class/graphics/fbcon/rotate; however, I'd prefer to use a kernel option in Grub, rather than including the above in the…
BMiner
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