Node:Menu entry editor, Next:Hidden menu interface, Previous:Menu interface, Up:Interface
The menu entry editor looks much like the main menu interface, but the lines in the menu are individual commands in the selected entry instead of entry names.
If an <ESC> is pressed in the editor, it aborts all the changes made to the configuration entry and returns to the main menu interface.
When a particular line is selected, the editor places the user at a special version of the GRUB command-line to edit that line. When the user hits <RET>, GRUB replaces the line in question in the boot entry with the changes (unless it was aborted via <ESC>, in which case the changes are thrown away).
If you want to add a new line to the menu entry, press <o> if adding a line after the current line or press <O> if before the current line.
To delete a line, hit the key <d>. Although GRUB does not support undo unfortunately, you can do almost the same thing by just returning to the main menu.