On Mon 08 Feb 2021 at 18:26:22 (-0800), David Christensen wrote: > On 2021-02-08 15:15, David Wright wrote: > > On Mon 08 Feb 2021 at 13:02:21 (-0800), David Christensen wrote: > > > On 2021-02-08 00:40, Marco Möller wrote: > > > > > > > You could bypass any password request during boot to the console > > > > and then fix it by setting the desired password newly. The boot > > > > parameter for bypassing all password request an right away > > > > becoming logged in as user root is: > > > > init=/sbin/sulogin --force > > > > > > That is interesting. But, how does the reader *use* that information[?] > > > ... > > > > Booting a Stretch system, I see a menu: > > > > > > GNU GRUB version 2.02~beta3-5+deb9u2 > > > > > > *Debian GNU/Linux > > > Advanced options for Debian GNU/Linux > > > > If I press 'e', it (GRUB?) appears to bring up an editor window that > > > contains a bunch of content that looks relevant. The last few lines > > > are: > > > > > > .... > > > echo 'Loading Linux 4.9.0-9-amd64 ...' > > > linux /vmlinuz-4.9.0-9-amd64 root=UUID=... ro noresume > > > echo 'Loading initial ramdisk ...' > > > initrd /initrd.img-4.9.0-9-amd64 > > > > … and that's the menu version of the commands outlined in 5.3.2. > > > Yes, [add the suggested parameters]to the linux line: it's a kernel > > parameter. > > > > Where is this documented? > > > > I always go to > > > > https://www.kernel.org/doc/html/v4.15/admin-guide/kernel-parameters.html > > > > (where v4.15 could be different). > > > > init= [KNL] > > Format: <full_path> > > Run specified binary instead of /sbin/init as init process. > > > > where KNL confirms it's a Kernel parameter. The introduction shows: > > > > BUGS= Relates to possible processor bugs on the said processor. > > KNL Is a kernel start-up parameter. > > BOOT Is a boot loader parameter. > > Thank you for the information. :-) > But, it still does not answer the question -- how does the reader > *use* the suggested "boot parameter"? > > My WAG (untested): > > 1. Power up the computer. > 2. The GRUB menu should be displayed: > > *Debian GNU/Linux > Advanced options for Debian GNU/Linux > > 3. Press the down arrow key to highlight "Advanced options for Debian > GNU/Linux". Press <Enter> to select it.
If you're heading for sulogin, I'm not sure it matters which line you pick, as it means s(ingle)u(se)rlogin. > 4. A second GRUB menu should be displayed (the OP should have a newer > kernel): Yes, you warned us you're using stretch. > *Debian GNU/Linux, with Linux 4.9.0-9-amd64 > Debian GNU/Linux, with Linux 4.9.0-9-amd64 (recovery mode) > > 5. Press the down arrow key to select the "... (recovery mode)" boot > entry. Press 'e' to edit it. > > 6. The GRUB editor should start and display the contents of the > selected boot entry. Look for the line that begins with 'linux'. Use > the cursor keys to move the insertion point to the end of that line > and add the following kernel boot parameters: > > init=/sbin/sulogin --force > > 7. "Press Ctrl+x or F10 to boot". > > Is the above correct? Yes. AIUI --force deals with the case where there is no root password/the root account is locked. But my understanding might be faulty as I always set a root password in decades-old tradition. As a result, I'm always prompted for a password. To reset *that*, I'd either boot up my other system on the disk, or boot from a stick/CD. > Questions: > > 1. How do I make a copy of a boot entry? (So that I can edit the > copy and keep the original.) > > 2. How do I insert a tab character with the GRUB editor? (Pressing > <Tab> causes the editor to attempt command completion.) I think Greg's guess was good. You don't need tabs or any other cosmetics. > 3. Will changes made to a boot entry with the GRUB editor persist for > subsequent boots? No. Just write down what you change, so that you can fold it in to your Grub configuration later if it worked. Cheers, David.