Re: Query about command line commands

[Bret Busby]

On 10/03/2015, Andrei Borzenkov <address@hidden> wrote:
> В Tue, 10 Mar 2015 14:46:46 +0800
> Bret Busby <address@hidden> пишет:
>
>> >>
>> >
>> > How do you get this grub command line interface? Does your system boot
>> > into
>> > it?
>> >
>>
>> By pressing <ESC> while booting, to display the PC-BSD "boot menu"
>> (which displays as the only boot option, the unbootable PC-BSD
>> installation) which has, at the bottom of the screen "Press enter to
>> boot the selected OS, 'e'to edit the commands before booting or 'c'
>> for a command line"; the command line being the GRUB CLI.
>>
>> > If you are in grub CLI you could boot Ubuntu (from your grub.cfg
>> > attached earlier) by using the same commands as in grub.cfg:
>> >
>> > set root=hd0,gpt12
>> > linux    /boot/vmlinuz-3.13.0-40-generic
>> > root=UUID=b96339a3-179e-4891-972e-658d35c454a6 ro
>
> This was one line which was wrapped by mailer. Sorry.
>
>> > initrd    /boot/initrd.img-3.13.0-40-generic
>> > boot
>> >
>> > You could try to omit root= but I do not know what Ubuntu does in this
>> > case. You can verify UUID by using "ls -l" on grub command line.
>> >
>>
>> When I entered the command starting with "initrd", I got the response
>> "disk 'UUID=<UUID>' not found".
>>
>
> That's because you did
>
> root=UUID=b96339a3-179e-4891-972e-658d35c454a6 ro
>
> which assigned string "UUID=b96339a3-179e-4891-972e-658d35c454a6" to
> $root variable. $root is default disk (partition) which is always
> searched when not given explicitly on command line.
>
> So once more
>
> line 1:
> set root=hd0,gpt12
>
> line 2 (if even you see it split in multiple lines by mailer):
> linux /boot/vmlinuz-3.13.0-40-generic
> root=UUID=b96339a3-179e-4891-972e-658d35c454a6 ro
>
> line 3:
> initrd /boot/initrd.img-3.13.0-40-generic
>
> line 4:
> boot
>
>
>>
>> > Oh, regarding platform - what
>> >
>> > echo $grub_platform
>> >
>> > in grub command line says?
>> >
>>
>> "
>> grub> echo $grub_platform
>> pc
>> "
>>
>
> As expected, you have no EFI boot. In this case on GPT disk on BIOS you
> can really have a single bootloader.
>
>>
>> But, whilst, mat the start of the boot process, is displayed
>>
>> "GRUB Loading
>> Welcome to GRUB"
>>
>> No reference to Microsoft, or, to MIS Windows, as a boot option, is
>> displayed.
>>
>
> Because your Windows installation does not have legacy bootloader and
> it is impossible to load EFI bootloader when you already booted in
> legacy BIOS mode.
>

Now, the above message, and my last message, appear to have passed
each other in transmission.

As shown in my last message, I have now restored the system, to (close
enough to) the state in which it existed, before the PC-BSD damage to
it.

So, now, the question arises; given that the system is a UEFI/GPT
system, with an EFI bootloader (?) that is not accessed, that points
to MS Windows 8, and, using an apparently BIOS-based bootloader (the
once again, operational GRUB) that points to Ubuntu Linux and Debian
Linux, how to I get a bootloader to point to all three of those
operating systems, so that the same bootloader, allows me to select
any one of those three operating systems, to load and run?

Does GRUB provide for that?

Thank you in anticipation.

-- 
Bret Busby
Armadale
West Australia
..............

"So once you do know what the question actually is,
 you'll know what the answer means."
- Deep Thought,
 Chapter 28 of Book 1 of
 "The Hitchhiker's Guide to the Galaxy:
 A Trilogy In Four Parts",
 written by Douglas Adams,
 published by Pan Books, 1992

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