Where is grub config file ubuntu

Improve this question. Sid Add a comment. Active Oldest Votes. Improve this answer. Leon Nardella Leon Nardella 1, 1 1 gold badge 15 15 silver badges 22 22 bronze badges. Then, when I tried changing it, it told me I did not have permissions to do so. Is there something else I need to change? B3tturTh3nU: You need to edit the file with root privileges. Careful with the editing! For 0, menu will not display even for a failed startup. Run update-grub after the change have been made. Special thanks to McCunha on Ubuntu Forums for the above tip.

The above change, however, still causes GRUB2 to boot into text graphics mode. Thus, an additional change is required. It can also limit access to specific entries for specific users, and can encrypt plain-text passwords for increased security. Custom Menu Entries GRUB 2 allows users to create customized menu selections which will be automatically added to the main menu when sudo update-grub is executed. Any other plaintext editor Vim, Emacs, Kate, Leafpad is fine too.

After that, reboots and shutdowns should start working properly. Its menu can be customized by the user to present a more visually-appealing menu by changing font colors, backgrounds and resolutions. Theme elements will include colors, fonts, progress indicators, menus, and labels. Both of these hold great promise but are not ready for release with Ubuntu 9. Check the Links section at the bottom of this page for references.

Information concerning upgrades from GRUB 0. I only discovered this while researching GRUB2 for a previous article. You can simply change the values of existing keys or add other keys that are not already in the file.

Section 5. I have never had needed to do anything other than modifying the values of some of the keys that are already in the grub default file. Let's look at what each of these keys means as well as some that don't appear in the grub default file. There are other keys that I have not covered here that you might find useful. Their descriptions are located in Section 5. This is accomplished with the following command. It also creates a "rescue" entry to provide a method for recovering from significant problems that prevent Linux from booting.

It is strongly recommended that you do not edit the grub. I encountered one problem with GRUB2 that could have serious consequences if you are not aware of it. The rescue kernel does not boot, instead, one of the other kernels boots. I found that to be the kernel at index 1 in the list, i. Additional testing showed that this problem occurred whether using the original grub.

I have tried this on both virtual and real hardware and the problem is the same on each. I only tried this with Fedora 25 so it may not be an issue with other Fedora releases. Note that the "recovery" kernel entry that is generated from the "rescue" kernel does work and boots to a maintenance mode login. This will generate usable recovery entries in the GRUB menu for each of the installed kernels. These recovery configurations work as expected and boot to runlevel 1—according to the runlevel command—at a command line entry that requests a password to enter maintenance mode.

You could also press Ctrl-D to continue a normal boot to the default runlevel. Understanding how to configure GRUB is important to be able to recover from or to circumvent various types of problems. I have had to boot to recovery or rescue mode many times over the years to resolve many types of problems. The entry in the chainloader line specifies the path of the.

See Using the command shell first. If unable to activate the standard shell, one possible solution is to boot using a live CD or some other rescue disk to correct configuration errors and reinstall GRUB.

However, such a boot disk is not always available nor necessary ; the rescue console is surprisingly robust. The available commands in GRUB rescue include insmod , ls , set , and unset. This example uses set and insmod. This introduces the linux and initrd commands, which should be familiar. After successfully booting the Arch Linux installation, users can correct grub. See Installation for details. This article or section is a candidate for moving to Arch boot process Troubleshooting.

The factual accuracy of this article or section is disputed. More information is available here. Read more about it here. It happens when the first partition starts just after the MBR block 63 , without the usual space of 1 MiB blocks before the first partition. If it does not, then see UEFI efibootmgr for instructions to use efibootmgr to create a menu entry. If GRUB loads but drops into the rescue shell with no errors, it can be due to one of these two reasons:. If the screen only goes black for a second and the next boot option is tried afterwards, according to this post , moving GRUB to the partition root can help.

The boot option has to be deleted and recreated afterwards. The entry for GRUB should look like this then:. If trying to boot Windows results in an "invalid signature" error, e.

Some have reported that other distributions may have trouble finding Arch Linux automatically with os-prober. This file and updating tool is available with the package lsb-release. These warnings will not prevent the system from booting, provided that everything has been done correctly, so you may continue with the installation. GRUB can take a long time to load when disk space is low.

GRUB may output error: unknown filesystem and refuse to boot for a few reasons. Use a partitioning tool of your choice to ensure this partition is located fully within the first 2 TiB, then reinstall and reconfigure GRUB. This error might also be caused by an ext4 filesystem having unsupported features set:. If you use grub-reboot to boot into another entry it will therefore be unable to update its on-disk environment.

Either run grub-reboot from the other entry for example when switching between various distributions or consider a different file system. See FS and workaround. This grub-rescue prompt has limited capabilities.

Use the following commands to complete the boot:. See this blog post for a better description. Note: Before attempting this method keep in mind that not all systems will be able to support this partitioning scheme. On GPT, however, there is no guaranteed unused space before the first partition.