I'm exploring how grub works, so I changed one of the lines in grub.cfg (I realize this isn't the way it's done, this is just for fun), to

and also the text of a couple of other menu entries.

But when I reboot, the changes don't show. The second answer to this question (https://askubuntu.com/questions/4373...-edit-grub-cfg) suggests that this should be possible. Am I overlooking something? I haven't updated grub or the kernel, so grub.cfg has the changes after the reboot. Any ideas?

if you want to put echos in your grub, use /etc/default/grub instead. Then update grub, then reboot, then look for your results. (in that order)

oh yes, 40_custom should work too.

All irrelevant. The OP is trying to learn, and changing the .cfg should certainly work for this purpose.

Maybe the wrong file is being updated.

no, any changes to grub.cfg will be removed as a new grub.cfg is generated at time of updating it using update-grub. ( grub2)

OP, are you dual-booting?

which file are you editing, and how (sudo...)?

also, it is worth noting that any kernel update will likely trigger an update-grub, which would overwrite your changes.

Are you doing this on an installed system or are you using a Live DVD or flash drive. If it is a Live system, no changes will be saved on reboot. If it is an installed system and you are making the change in grub.cfg file and saving the change as root (sudo), then the change should be there on reboot. If you run grub-mkconfig after the change is made, it will be lost. A kernel update will usually run grub-mkconfig so any edits to grub.cfg will also be lost in this case.

@yancek, @BW-userx: This is on an installed system, and I am not running grub-mkconfig, or updating the kernel - grub.cfg has my changes after rebooting, as well.

@ondoho: Yes, I am dual booting, OSX with ArchLinux. I think I changed boot.efi or something to recognize Arch, so it starts with Apple's booting screen, and then it passes on to grub once I select Arch. It's the grub.cfg corresponding to Arch I'm editing (I hope). Could this be a problem?

Also, I'm using sudo emacs grub.cfg.

@syg00: I'm positive I'm changing /boot/grub/grub.cfg, is there any other file that grub takes information from?

dual booting with another linux might have been important, but i don't think osx uses grub...

editing /boot/grub/grub.cfg should surely show some effect.
are you sure that nothing performs a grub update in between?
if yes, i suggest you keep trying different things with your /boot/grub/grub.cfg until you can see the effect.
BTW, there's a package to preview grub themes, in AUR. so you don't have to reboot.

There are numerous other grub files but none relevant for your purposes. Are you able to boot Arch? If you can you might post the relevant menuentries, at least the section(s) which you changed so we can see where they are entered.

default/grub

it keeps the info