grub-mkpasswd-pbkdf2(1) on Linux
The text 51eccecef368, as Debian 9 (Stretch) shipped it.
generate hashed password for GRUB
Flags it lists
-
--buflen -
--help -
--iteration-count -
--salt -
--usage -
--version -
-? -
-V -
-c -
-l -
-s