grub-mkrelpath - make a system path relative to its root
grub-mkrelpath [OPTION...] PATH
Transform a system filename into GRUB one.
give this help list
give a short usage message
print program version
Report bugs to <bug-grub@gnu.org>.
The full documentation for grub-mkrelpath is maintained as a Texinfo manual. If the info and grub-mkrelpath programs are properly installed at your site, the command
info grub-mkrelpath
should give you access to the complete manual.