grub
GRand Unified Bootloader for Linux systems
TLDR
Enter GRUB shell
$ sudo grub
Install GRUB to disk$ sudo grub-install /dev/sda
Update GRUB configuration$ sudo update-grub
Generate config file$ sudo grub-mkconfig -o /boot/grub/grub.cfg
Check GRUB version$ grub-install --version
SYNOPSIS
grub [options]
grub-install [options] device
DESCRIPTION
GRUB (GRand Unified Bootloader) is the standard bootloader for Linux systems. It loads the kernel and initrd, presenting a boot menu for system selection.
GRUB 2 supports multiple filesystems, LVM, RAID, and encrypted partitions. It provides rescue mode for system recovery and scripting for advanced configurations.
PARAMETERS
--root-directory DIR
Install to alternate root.--boot-directory DIR
Boot directory location.--target TARGET
Target platform.--recheck
Probe devices again.--removable
Install for removable media.--help
Display help information.
CONFIGURATION
/etc/default/grub
Main GRUB configuration file controlling default boot entry, timeout, kernel parameters, and display settings./etc/grub.d/
Directory containing scripts that generate the grub.cfg file. Custom entries can be added here./boot/grub/grub.cfg
Generated configuration file. Do not edit directly; use grub-mkconfig to regenerate.
CAVEATS
Misconfiguration can prevent booting. Keep rescue media available. GRUB 2 differs from legacy GRUB.
HISTORY
GRUB was created as part of the GNU Project. GRUB 2 was released in 2002 as a complete rewrite with enhanced features.
SEE ALSO
grub-mkconfig(8), update-grub(8), grub-install(8)