There are major differences between legacy GRUB and the new GRUB2 bootloaders, so the last thing you want to do is run commands specific to one version on the other, as this could render your system unbootable (which you could fix, but with some time spent fiddling). If unsure of your GRUB version, enter the following command in a terminal:
The output will look like:
grub-install (GNU GRUB 1.98-1ubuntu6)
In the case of the example, it is showing that GRUB2 is the bootloader. Don’t be fooled by the “1” in the version number, as legacy GRUB will be reported as 0.97 (or earlier).
Here are some more GRUB-related posts: