Add GRUB entry for extra option to boot in text mode?

[dazz..]

Can someone please give me a brief explanation of what is this all about?

linux /vmlinux root=[I]<blah blah>
[/I]initrd /initrd.img

these are grub commands, right?

[Qqmike]

If you already know what you are doing, this basic intro may be helpful ;-)
The GRUB 2 Manual
https://www.gnu.org/software/grub/manual/grub.html
E.g.,

16.3.37 linux

Command: linux file …

Load a Linux kernel image from file. The rest of the line is passed verbatim as the kernel command-line. Any initrd must be reloaded after using this command (see initrd).

On x86 systems, the kernel will be booted using the 32-bit boot protocol. Note that this means that the ‘vga=’ boot option will not work; if you want to set a special video mode, you will need to use GRUB commands such as ‘set gfxpayload=1024x768’ or ‘set gfxpayload=keep’ (to keep the same mode as used in GRUB) instead. GRUB can automatically detect some uses of ‘vga=’ and translate them to appropriate settings of ‘gfxpayload’. The linux16 command (see linux16) avoids this restriction.

And initrd,
https://www.gnu.org/software/grub/ma...ub.html#initrd

[oshunluvr]

Can someone please give me a brief explanation of what is this all about?

linux /vmlinux root=[I]<blah blah>
[/I]initrd /initrd.img

these are grub commands, right?

Part of the grub boot menu stanzas.

I believe the suggestion is to edit your 40_custom file in /etc/grub.d using the first menuentry from /boot/grub/grub.cfg and edit these two lines:

linux /boot/[B]vmlinuz-4.10.0-22-generic.efi.signed[/B] root=UUID=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ro [B]quiet splash[/B]
initrd /boot/[B]initrd.img-4.10.0-22-generic[/B]

to look like this:

linux /boot/[B]vmlinuz[/B] root=UUID=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ro [B]text[/B]
initrd /boot/[B]initrd.img[/B]

then you won't have to keep re-editing 40_custom or use any script action at all. This will continue to do what you want without further work.

The reason this works is Kubuntu (all *buntu's) create a symlinks in the root folder that point to the most current kernel image (vmlinux) and initramfs (initrd.img) and the previous version. If you do this command in a terminal:

ls -l / |grep lrwx

you'll see these symlinks:

lrwxrwxrwx   1 root   root     33 Jun  7 09:36 initrd.img -> boot/initrd.img-4.10.0-22-generic
lrwxrwxrwx   1 root   root     33 May 21 09:10 initrd.img.old -> boot/initrd.img-4.10.0-21-generic
lrwxrwxrwx   1 root   root     30 Jun  7 09:36 vmlinuz -> boot/vmlinuz-4.10.0-22-generic
lrwxrwxrwx   1 root   root     30 May 21 09:10 vmlinuz.old -> boot/vmlinuz-4.10.0-21-generic

[dazz..]

That makes complete sense. Simple and elegant solution

[dazz..]

For the sake of completion, here's the final solution (content of /etc/grub.d/40_custom)

menuentry '[COLOR=#ff0000][B]Ubuntu (HEADLESS)[/B][/COLOR]' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' {        
     recordfail
     load_video
     gfxmode $linux_gfx_mode
     insmod gzio
     if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
     insmod part_gpt
     insmod ext2
     set root='hd0,gpt2'
     if [ x$feature_platform_search_hint = xy ]; then
       search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt2 --hint-efi=hd0,gpt2 --hint-baremetal=ahci0,gpt2 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
     else
       search --no-floppy --fs-uuid --set=root xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
     fi
[COLOR=#ff0000][B]        linux /vmlinuz root=UUID=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ro text systemd.unit=multi-user.target[/B][/COLOR]
[COLOR=#ff0000][B]        initrd /initrd.img[/B][/COLOR]
}

[dazz..]

Another interesting command I found:

sudo grub-reboot "Ubuntu (HEADLESS)"
sudo reboot

..to reboot the system and load the newly created stanza labeled as "Ubuntu (HEADLESS)"