Example person's questions

I am talking about this upgrade tool: http://archive.ubuntu.com/ubuntu/dists/jammy/main/dist-upgrader-all/current/jammy.tar.gz which I am sure the do-release-upgrade uses to upgrade to 22.04 from 21.10. I found it in https://changelogs.ubuntu.com/meta-release.

During the upgrade, what I have observed is:

1. Updates sources.list.
2. Disables third-party repositories to avoid errors with them (can be enabled again after the upgrade).
3. Runs apt update
4. Upgrades all the packages using apt: upgrade and dist-upgrade
5. Has a list called demoted.cfg (which is a list of packages that are not needed to the newer Ubuntu version and are meant to be deleted if they aren't automatically installed, etc.). Gets the packages in the list, checks which of them are manually installed, and combines them to the list of apt autoremove, and removes all of them after asking you.
6. Also removes the Firefox that was installed using apt. Or more clearly: it removes packages listed in dep2snap.cfg (and installs the snap version?). Somewhere around these steps.
7. Reboots the system

Are there any other steps here that I am missing? I need to know as I need to revert any unexpected changes to the system.
Example: Changes to the system that helps the system to be stable during the upgrade. But aren't needed after the upgrade.

Note: All the .cfg files mentioned above are in the upgrade tool that do-release-upgrade uses. Which I have listed above.

What is that .libs directory in the Desktop created by, usually? I've just seen it for the first time. It contains nothing in it, but I am suspicious of it as I haven't run anything on the Desktop recently. I run a lot of gcc and compile all the time, but not on the Desktop. My gcc commands do not contain any .libs in the command. My programs do not write/create any files/folders called .libs. history | grep libs shows no command containing libs.

Side note: Since 21.10, I've been seeing other directories such as firefox.tmp in the Downloads folder. But that is obviously firefox's snap version's way of things.

ls -la Desktop:

drwxrwxr-x  2 user user      4096 Nov 24 00:00  .libs

It says 'Nov 24', but it wasn't there till today.

By my screenshots in the past, I am pretty sure that this was not there by default after the installation of Ubuntu.

My ubuntu default permissions suddenly changed from 644 to 664?

Usually, I am familiar with the permissions 644 and 755 for files and directories respectively.

But now when I create a new dir or a new file, the permissions are 664 and 775.

Is 664 and 775 the default permissions actually? But, I haven't noticed them before because I do not really look at file permissions every day.

Even folders created with nautilus do this. And, as there is no button to create a file in nautilus, I use the command line, and I am pretty familiar with the terminal.

I am using Ubuntu 20.10 Minimal Desktop version.

Now this is what happens:

$ ls -la
total 8
drwxrwxr-x 2 exampleuser exampleuser 4096 Mar  5 12:22 .
drwxr-xr-x 6 exampleuser exampleuser 4096 Mar  5 12:23 ..
$ mkdir example
$ ls -la
total 12
drwxrwxr-x 3 exampleuser exampleuser 4096 Mar  5 12:25 .
drwxr-xr-x 6 exampleuser exampleuser 4096 Mar  5 12:23 ..
drwxrwxr-x 2 exampleuser exampleuser 4096 Mar  5 12:25 example

How can I make timeshift take a backup of the whole system? I am unable to find any tutorials to do this! I am using the default config.

Accidentally ran wget -O- https://dev.mysql.com/get/Downloads/MySQL-8.0/mysql-boost-8.0.22.tar.gz with the -O- thing, and it outputted random stuff to terminal. Is it possible that it could've done damage to the system? This is a production server. pls help.

How can I remove the domain name from the domainname command on ubuntu? I am unable to find anything related to this. I set my domain name using domainname example.com

Thanks in advance!

How can I stop Apt from marking packages as manual when you run the "apt install " command?

For example, Accidentally, when I run apt install <package-which-is-already-there> (of a package which is already there), it marks the package as manually installed.

Which I hate a lot. How can I stop apt from doing this? It even messes up things sometimes.

How can I remove all the users and groups associated with removed (purged) programs?

For example, I install exim. It created a group and a user named Debian-exim.

I then use it for a while, and remove it using apt-get purge exim*. And then, it removes all the files associated with it. But, it does not remove the users and groups created by the program 'exim'. I have installed and removed several programs, so, I am not sure how many users are left behind in my system. I want to remove all the unwanted users automatically when I uninstall a program, and I also want to remove all the unwanted users that exist currently in my system. How can I achieve that?

How can I configure ufw so that it blocks any connection to port 443 using the http protocol, but not the https protocol. So what I mean is:

http://example.com:443 (Deny any connection) https://example.com:443 (Allow any connection)

Can anyone please help me on this? Thanks in advance!

Edit:

If there is any other program for doing this, please let me know! Thanks!

I installed Exim and mailutils (For receiving) for sending mails through PHP in Ubuntu. After I installed it, I ran the command dpkg-reconfigure exim4-config, I was asked to set the mail recipient for root and postmaster (I was in a rush). I entered root there (not sure if I made a typo). the next time I try to reconfigure Exim, I am not able to set that one setting. How can I set that setting again? Please let me know. I am not able to find the solution for this myself.