You can use the command grub for installing GRUB under your operating systems and for a testbed when you add a new feature into GRUB or when fixing a bug. grub is almost the same as the Stage2, and, in fact, it shares the source code with the Stage 2 and you can use the same commands (see CommandList) in grub. It is emulated by replacing BIOS calls with UNIX system calls and libc functions.
Options
The command grub accepts the following options:
--help Print a summary of the command-line options and exit. --version Print the version number of GRUB and exit. --verbose Print some verbose messages for debugging purpose. --device-map=file Use the device map file file. The format is described in Device map. --no-floppy Do not probe any floppy drive. This option has no effect if the option --device-map is specified (see Device map). --probe-second-floppy Probe the second floppy drive. If this option is not specified, the grub shell does not probe it, as that sometimes takes a long time. If you specify the device map file (see Device map), the grub shell just ignores this option. --config-file=file Read the configuration file file instead of /boot/grub/menu.lst. The format is the same as the normal GRUB syntax. See Filesystem, for more information. --boot-drive=drive Set the stage2 boot_drive to drive. This argument should be an integer (decimal, octal or hexadecimal). --install-partition=par Set the stage2 install_partition to par. This argument should be an integer (decimal, octal or hexadecimal). --no-config-file Do not use the configuration file even if it can be read. --no-curses Do not use the screen handling interface by the curses even if it is available. --batch This option has the same meaning as `--no-config-file --no-curses'. --read-only Disable writing to any disk. --hold Wait until a debugger will attach. This option is useful when you want to debug the startup code.