documentation: Clarify documentation for special environment variable "default".

The current documentation for the special environment variable
"default" is confusing and unclear.  This patch attempts to clean it
up.

In particular, the current documentation refers to the "number or
title", but then in the example it gives, the menu entries and
submenus all have numbers *in* their title; furthermore, there is no
example given about how to choose the number, or any indication about
whether counting is zero-indexed or 1-indexed.

Having a cleaner example and presenting all variants (numeric, title,
and id) should make it clearer to the user.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
This commit is contained in:
Daniel Kahn Gillmor 2017-02-03 12:32:25 +01:00 committed by Vladimir Serbinenko
parent 5412028d19
commit bf94ef7fbd
1 changed files with 20 additions and 17 deletions

View File

@ -3218,9 +3218,10 @@ source for more details.
@node default @node default
@subsection default @subsection default
If this variable is set, it identifies a menu entry that should be selected If this variable is set, it identifies a menu entry that should be
by default, possibly after a timeout (@pxref{timeout}). The entry may be selected by default, possibly after a timeout (@pxref{timeout}). The
identified by number or by id. entry may be identified by number (starting from 0 at each level of
the hierarchy), by title, or by id.
For example, if you have: For example, if you have:
@ -3236,24 +3237,26 @@ then you can make this the default using:
default=example-gnu-linux default=example-gnu-linux
@end example @end example
If the entry is in a submenu, then it must be identified using the titles of If the entry is in a submenu, then it must be identified using the
each of the submenus starting from the top level followed by the number or number, title, or id of each of the submenus starting from the top
title of the menu entry itself, separated by @samp{>}. For example, take level, followed by the number, title, or id of the menu entry itself,
the following menu structure: with each element separated by @samp{>}. For example, take the
following menu structure:
@example @example
Submenu 1 GNU/Hurd --id gnu-hurd
Menu Entry 1 Standard Boot --id=gnu-hurd-std
Menu Entry 2 Rescue shell --id=gnu-hurd-rescue
Submenu 2 Other platforms --id=other
Submenu 3 Minix --id=minix
Menu Entry 3 Version 3.4.0 --id=minix-3.4.0
Menu Entry 4 Version 3.3.0 --id=minix-3.3.0
Menu Entry 5 GRUB Invaders --id=grub-invaders
@end example @end example
``Menu Entry 3'' would then be identified as The more recent release of Minix would then be identified as
@samp{Submenu 2>Submenu 3>Menu Entry 3}. @samp{Other platforms>Minix>Version 3.4.0}, or as @samp{1>0>0}, or as
@samp{other>minix>minix-3.4.0}.
This variable is often set by @samp{GRUB_DEFAULT} (@pxref{Simple This variable is often set by @samp{GRUB_DEFAULT} (@pxref{Simple
configuration}), @command{grub-set-default}, or @command{grub-reboot}. configuration}), @command{grub-set-default}, or @command{grub-reboot}.