Installing from live-USB-stick preserves or destroys existing user data?

[Janis Papanagnou]

After a non-successful upgrade from version 18 to 20 my system became
inconsistent and doesn't boot anymore. To get access to the user data
in the home directories I tried to access the system through a booted
live system on an USB-stick. From that instance I see the directories
but cannot enter them due to lacking access permissions of the live
user. Switching to root or sudo seems impossible when a root password
isn't available in the live-system context. Or am I missing an access
option?

As far as I see another option I have would be to install the system
from the live version, but will the existing home directories be
preserved or deleted in that process?

Janis

[jjb]

Post by Janis Papanagnou
After a non-successful upgrade from version 18 to 20 my system became
inconsistent and doesn't boot anymore. To get access to the user data
in the home directories I tried to access the system through a booted
live system on an USB-stick. From that instance I see the directories
but cannot enter them due to lacking access permissions of the live
user. Switching to root or sudo seems impossible when a root password
isn't available in the live-system context. Or am I missing an access
option?
As far as I see another option I have would be to install the system
from the live version, but will the existing home directories be
preserved or deleted in that process?
Janis

Open terminal, type"
sudo su
and press <Enter> if asked for a password. That should be all...

[Janis Papanagnou]

Post by jjb

[...] Or am I missing an access option?

Open terminal, type"
sudo su
and press <Enter> if asked for a password. That should be all...

Right. I now have root access and I'm able to back up that formerly
inaccessible user data. Thanks!

Janis

[Chris Elvidge]

Post by Janis Papanagnou
After a non-successful upgrade from version 18 to 20 my system became
inconsistent and doesn't boot anymore. To get access to the user data
in the home directories I tried to access the system through a booted
live system on an USB-stick. From that instance I see the directories
but cannot enter them due to lacking access permissions of the live
user. Switching to root or sudo seems impossible when a root password
isn't available in the live-system context. Or am I missing an access
option?

I think you're finding walls where no walls exist - you do not need a
root password for sudo, only your user password.

I can't speak directly for Ubuntu, but booting the iso of Linux Mint
Debian Edition allows "sudo -i" in a terminal to get root with the
default autologin user mint - no password required.

Post by Janis Papanagnou
As far as I see another option I have would be to install the system
from the live version, but will the existing home directories be
preserved or deleted in that process?
Janis

[Janis Papanagnou]

Post by Chris Elvidge

[...] Or am I missing an access option?

I think you're finding walls where no walls exist -

Yeah, most likely. :-)

Post by Chris Elvidge
you do not need a root password for sudo, only your user password.

The problem was that my user (id and password) was not available
in the live-system context.

Post by Chris Elvidge
I can't speak directly for Ubuntu, but booting the iso of Linux Mint
Debian Edition allows "sudo -i" in a terminal to get root with the
default autologin user mint - no password required.

I tried the previous poster's suggestion "sudo su" and it worked
also without password. So I'm okay for the moment. Thank you.

Janis

[wicklowham]

Post by Janis Papanagnou
After a non-successful upgrade from version 18 to 20 my system became
inconsistent and doesn't boot anymore. To get access to the user data
in the home directories I tried to access the system through a booted
live system on an USB-stick. From that instance I see the directories
but cannot enter them due to lacking access permissions of the live
user. Switching to root or sudo seems impossible when a root password
isn't available in the live-system context. Or am I missing an access
option?
As far as I see another option I have would be to install the system
from the live version, but will the existing home directories be
preserved or deleted in that process?
Janis

When a new version comes out ,I always first save the home directory
with all its files and subsequently install the new version from scratch
.That has never failed me .
An option is to have and keep the Home directory on a separate partition
,although I have never done that.

Frank in County Wicklow - Ireland

[Dirk T. Verbeek]

Post by wicklowham

Post by Janis Papanagnou
After a non-successful upgrade from version 18 to 20 my system became
inconsistent and doesn't boot anymore. To get access to the user data
in the home directories I tried to access the system through a booted
live system on an USB-stick. From that instance I see the directories
but cannot enter them due to lacking access permissions of the live
user. Switching to root or sudo seems impossible when a root password
isn't available in the live-system context. Or am I missing an access
option?
As far as I see another option I have would be to install the system
from the live version, but will the existing home directories be
preserved or deleted in that process?
Janis

When a new version comes out ,I always first save the home directory
with all its files and subsequently install the new version from scratch
.That has never failed me .
An option is to have and keep the Home directory on a separate partition
,although I have never done that.
Frank    in County Wicklow  - Ireland

I have my home directory and root on their own partitions.
Yes I make a backup of /home (simple copy) before upgrading or more
often doing a fresh install.
During the install I have the root directory and partition reformatted
and leave the /home alone, no formatting.
Providing you use the same username and password all will work as
before, in many years I've never had to revert to the backup.

[Janis Papanagnou]

Post by wicklowham
When a new version comes out ,I always first save the home directory
with all its files and subsequently install the new version from scratch
.That has never failed me .

Well, the updates usually worked flawlessly. Just this upgrade failed.
As usual I used, as with the update, the built-in automatism also for
the upgrade. Didn't expect any issues. But the Chrome update required
some 'snap' method, and that process just hung. - I think it is a bug
that the system can get in an inconsistent state at that stage during
a very long update process, so that a reboot will permanently fail.
IMO it should build the new environment (long time scale), then switch
to the new one (short time scale) while both versions still available;
it would make the update more reliable. (And I thought that this would
already be done that way; I'm puzzled.)

Post by wicklowham
An option is to have and keep the Home directory on a separate partition
,although I have never done that.

On this system I used a standard installation, with just one hard disk,
used the "default" file system, and no specific partitioning.

On the other box, the one I primarily use, I have a more elaborated
setup, with SSD and HDDs, multi-disk ZFS, backup devices, and a more
sensible choice of and mapping to partitions.

Janis

[Henry Crun]

Post by Janis Papanagnou

Post by wicklowham
When a new version comes out ,I always first save the home directory
with all its files and subsequently install the new version from scratch
.That has never failed me .

Well, the updates usually worked flawlessly. Just this upgrade failed.
As usual I used, as with the update, the built-in automatism also for
the upgrade. Didn't expect any issues. But the Chrome update required
some 'snap' method, and that process just hung. - I think it is a bug
that the system can get in an inconsistent state at that stage during
a very long update process, so that a reboot will permanently fail.
IMO it should build the new environment (long time scale), then switch
to the new one (short time scale) while both versions still available;
it would make the update more reliable. (And I thought that this would
already be done that way; I'm puzzled.)

Post by wicklowham
An option is to have and keep the Home directory on a separate partition
,although I have never done that.

On this system I used a standard installation, with just one hard disk,
used the "default" file system, and no specific partitioning.
On the other box, the one I primarily use, I have a more elaborated
setup, with SSD and HDDs, multi-disk ZFS, backup devices, and a more
sensible choice of and mapping to partitions.
Janis

The "Big Hammer" way of solving snap probles is removing snap.
I found https://cialu.net/how-to-disable-and-remove-completely-snaps-in-ubuntu-linux/ to be useful.

If you *really* need chromium, there is a way (which escapes my memory right now) of installing it on Ubuntu from a
Debian repository. Anything else you have installed using snap can probably be installed using apt-get.

[Andrei Z.]

Henry Crun wrote:
<snip>

Post by Henry Crun
If you *really* need chromium, there is a way (which escapes my memory
right now) of installing it on Ubuntu from a Debian repository. Anything
else you have installed using snap can probably be installed using apt-get.

Chromium Browser (Deb) Now Available to Install via Linux Mint 20
Repository - UbuntuHandbook

https://ubuntuhandbook.org/index.php/2020/11/chromium-browser-deb-available-linux-mint-20/

[Janis Papanagnou]

Post by Henry Crun

Post by Janis Papanagnou
Well, the updates usually worked flawlessly. Just this upgrade failed.
As usual I used, as with the update, the built-in automatism also for
the upgrade. Didn't expect any issues. But the Chrome update required
some 'snap' method, and that process just hung. [...]

The "Big Hammer" way of solving snap probles is removing snap.
I found
https://cialu.net/how-to-disable-and-remove-completely-snaps-in-ubuntu-linux/
to be useful.

You confirm a statement about 'snap' that I've already heard elsewhere.
But I wasn't even aware that I installed that 'snap' thing. Thanks for
the link, it's useful, and after my recovery I'm going to purge 'snap'
if I still find it in my original re-installed system.

Post by Henry Crun
If you *really* need chromium, there is a way (which escapes my memory
right now) of installing it on Ubuntu from a Debian repository. Anything
else you have installed using snap can probably be installed using apt-get.

I don't use Chromium. I may have installed it to check it out (don't
recall at the moment) in times where Firefox slowed down, to see whether
other software performs better. But I certainly don't "need" 'snap'.

Janis