grub-mkconfig

Print configuration to stdout (dry run)

$ sudo grub-mkconfig

$ sudo grub-mkconfig -o /boot/grub/grub.cfg

$ grub-mkconfig --help

$ grub-mkconfig --version

grub-mkconfig [OPTION]

grub-mkconfig generates a GRUB bootloader configuration file by processing system settings and detecting installed operating systems. It is typically used after kernel updates or when modifying boot parameters.
The command reads settings from /etc/default/grub and executes scripts in /etc/grub.d/ to produce the final grub.cfg file.

-o, --output=FILE

Write the generated configuration to FILE instead of stdout

Display help message and exit

Display version information and exit

/etc/default/grub

Main settings file controlling timeout, default entry, kernel parameters, and display options.

Directory of scripts executed during configuration generation. Custom boot entries can be added here.

This command should be run as root. The generated configuration depends on scripts in /etc/grub.d/ and settings in /etc/default/grub. After making changes to GRUB settings, always run grub-mkconfig to regenerate the configuration.

grub-mkconfig is part of GRUB 2 (GRand Unified Bootloader), which replaced the original GRUB Legacy. It provides automatic detection of installed kernels and operating systems.

grub-install(8), update-grub(8), grub-set-default(8)