Re: How to remove variable from GRUB environment block

[Ulf Zibis]

Am 12.02.2013 16:21, schrieb Andrey Borzenkov:
> В Tue, 12 Feb 2013 14:57:53 +0100
> Ulf Zibis <address@hidden> пишет:
>
> > I'm not clearly sure, but I see different syntax in my grub.cfg, which I interpret as 
> > "test for existence":
> No. Both just test whether result of variable substitution is empty or
> not. It is empty if variable is not defined or if it is defined but
> empty.
>
> > if [ x"${feature_menuentry_id}" = xy ]; then
> >     ...
> >
> > if [ "${prev_saved_entry}" ]; then
> >     set saved_entry="${prev_saved_entry}"
> > fi

Thanks for your clarification! But wouldn't this be a nice feature to have both?

I still bother what the difference is with the above syntax. Is there a syntax 
tutorial somewhere?

I guess, the following third syntax is redundantly the same:

if [ ! "${feature_menuentry_id}" = "" ]; then
   ...


-Ulf