The command-line shell tool for the GRUB (GRand Unified Bootloader) multi-boot loader.
The grub command is the command-line shell interface for the legacy GRUB bootloader.
grub [options]
--batch: Enable batch mode;
--boot-drive=<drive>: Specify the stage2 boot drive;
--config-file=<file>: Specify the stage2 configuration file;
--device-map=<file>: Specify the device map file;
--help: Display help information;
--install-partition=<partition>: Specify the stage2 installation partition;
--no-config-file: Do not use a configuration file;
--no-pager: Do not use the internal pager;
--preset-menu: Use a preset menu;
--probe-second-floppy: Probe the second floppy drive;
--read-only: Read-only mode.
Using the grub command to boot a damaged Linux system. This is useful when the system cannot boot automatically, for example, when the screen shows only a grub> prompt but the data on the hard drive is intact.
In the grub> shell, you can manually boot the system using four main commands: root, kernel, initrd, and boot.
root (hd and press TAB twice to list possible disk devices (e.g., hd0, hd1).hd0) and type root (hd0, then press TAB twice to list partitions. You can identify the Linux partition (type 0x83)./boot directory, e.g., root (hd0, 1), and press Enter.cat /boot/vm and press TAB twice. If files starting with vmlinuz- appear, this is likely the /boot partition.cat /boot/initrd followed by TAB twice.cat /sbin/init followed by TAB twice. If found, this is the / partition. If not, retry with another root (hd0, N) partition until you find /sbin/init.Once the partitions are identified, execute the following:
root (hd0,1) # Assume /dev/hda2 is the /boot partition
kernel /boot/vmlinuz-2.6.15-26-386 ro root=/dev/hda3 # Assume /dev/hda3 is the / partition
initrd /boot/initrd.img-2.6.15-26-386
boot
This will boot the system.