On 25 July 2018 at 13:45, Lennart Sorensen via talk <talk@gtalug.org> wrote:
There's probably a GRUB-specific mailing list or forum, but I thought I would try here first ...
GRUB has a DSL ( https://en.wikipedia.org/wiki/Domain-specific_language ) that looks a lot like shell scripting. Most people never see it as it's used to generate the menus we use at boot-time and they see only the
On Wed, Jul 25, 2018 at 12:54:39PM -0400, Giles Orr via talk wrote: menus,
but it can do some interesting things - particularly when you're dealing with multi-boot USB sticks. Here's a simple but slightly useful example:
function cpuinfo { # only able to determine: 32/64 bit, and is it PAE echo "GRUB's ability to analyse processors is limited, we can only tell you:" if cpuid -p; then pae_assessment="PAE" else pae_assessment="NO PAE" fi if cpuid -l; then echo "64-bit processor, $pae_assessment" else echo "32-bit processor, $pae_assessment" fi }
But it has some nasty limitations that are frustrating me: - no pipes - no command substitution - no file globbing
Actually it does file globbing if you load the regexp module.
Apparently this works:
insmod regexp for i in /boot/*; do echo $i; done
Or:
grub> ls /boot/* error: file `/boot/*' not found. grub> insmod regexp grub> ls /boot/* unicode.pf2 i386-pc/ locale/ fonts/ grubenv grub.cfg config-4.16.0-2-amd64 ...
Thank you! I don't think that's documented anywhere, and it doesn't strike me as being in any way obvious. -- Giles https://www.gilesorr.com/ gilesorr@gmail.com