grubby
command-line bootloader configuration tool for Red Hat systems
TLDR
Add kernel boot arguments to all kernel menu entries
SYNOPSIS
grubby [options]
DESCRIPTION
grubby is a command-line tool for updating and modifying bootloader configuration on Red Hat-based systems. It works with GRUB, GRUB2, and zipl (for s390 systems), providing a unified interface for boot configuration changes.
The tool modifies kernel command-line arguments, manages boot entries, and sets default kernels without directly editing configuration files. On modern Fedora/RHEL systems using GRUB2 with BLS (Boot Loader Specification), grubby modifies the individual kernel entry files in /boot/loader/entries/.
PARAMETERS
--info=KERNEL
Display boot information for specified kernel (or ALL)--update-kernel=KERNEL
Update specified kernel (ALL, DEFAULT, or path)--args=ARGS
Add kernel arguments--remove-args=ARGS
Remove kernel arguments--set-default=KERNEL
Set default boot kernel--default-kernel
Display path of default kernel--default-index
Display index of default kernel--add-kernel=PATH
Add a new kernel entry--remove-kernel=PATH
Remove a kernel entry--title=TITLE
Set title for new kernel entry
CAVEATS
Behavior varies between GRUB Legacy, GRUB2, and BLS configurations. Some options may not work with all bootloader configurations. Changes take effect on next boot. Always verify configuration after changes.
HISTORY
grubby was developed by Red Hat to simplify bootloader management across different configurations. It became essential for automated system management and kernel updates on Red Hat-based distributions.
SEE ALSO
grub-mkconfig(8), grub-set-default(8), kernel-install(8)