Re: Probing for the existence of a device.

[Andrey Borzenkov]

В Sun, 23 Jun 2013 23:19:11 +0100
João Ricardo Sares Teles de Matos <address@hidden> пишет:

> 
> However, it doesn't work as one would initially expect.
> This example illustrates the problem:
> 
> for drive in (hd0) (hd1) (hd2); do
>   menuentry "Echo the value of \$drive (it should be $drive)" {
>        echo "The value of \$drive is $drive"
>        sleep 5
>   }
> done
> 
> This creates three menu entries, with (hd0), (hd1) and (hd2) in the title.
> When choosing the menu, however, all three entries echo "The value of $drive 
> is (hd2)".
> 
> The expansion of $drive within the menuentry is deferred to the moment when 
> the menu entry is activated, which causes all menu entries to expand to the 
> last value assigned to the variable drive, (hd2).
> 

Pass value of $drive as parameter into menuentry. grub implicitly adds
"setparams arg1 arg2 ..." for every non-option argument as the very
first menuentry body statement.

for drive in (hd0) (hd1) (hd2); do
  menuentry "Echo the value of \$drive (it should be $drive)" $drive {
       echo "The value of \$drive is $2"
       sleep 5
  }
done

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