I'm unable to expand my WSL, using "apt install"

On my Windows PC, I have a Windows subsystem for Linux (WSL), more exactly the Ubunto app of Canonical Group Limited.

When I want to install new tools or programs, I use apt install but this seems not to work:

Linux Prompt>sudo apt install libxml2-utils
[sudo] password for <username>:
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package libxml2-utils

This can, in my very humble opinion, be caused by two things:

  1. Either WSL has a problem
  2. Either my Windows machine, hosting the WSL, blocks the WSL request.

As far as the first is concerned, this command gives no results:

Linux Prompt>sudo find /var -mtime -5

In other words, there would not be any logs in the /var directory for the last 5 days? Don't expect me to believe that. So, where's the /var/adm/messages of my WSL?

As far as the second is concerned, I'm thinking here about the Firewall, but although logging settings mention every needing to be logged, the "pfirewall.log" file is empty (size=0Kb).

At first glance, Windows' event log is also not giving any information.

Does anybody know what's going on and how I can install updates on my WSL?

Thanks in advance

Edit after mtak's answer

I've launched apt get-update, it didn't work, due to some internet site which is claimed not to be correct (which I doubt heavily: I believe my computer can't contact that site, causing the error messages), hereby the output of apt-get update:

Get:1 http://archive.ubuntu.com/ubuntu focal InRelease
Err:1 http://archive.ubuntu.com/ubuntu focal InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:2 http://security.ubuntu.com/ubuntu focal-security InRelease
Err:2 http://security.ubuntu.com/ubuntu focal-security InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:3 http://archive.ubuntu.com/ubuntu focal-updates InRelease
Err:3 http://archive.ubuntu.com/ubuntu focal-updates InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:4 http://archive.ubuntu.com/ubuntu focal-backports InRelease
Err:4 http://archive.ubuntu.com/ubuntu focal-backports InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Reading package lists... Done
N: See apt-secure(8) manpage for repository creation and user configuration details.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
E: The repository 'http://archive.ubuntu.com/ubuntu focal InRelease' is not signed.
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
N: See apt-secure(8) manpage for repository creation and user configuration details.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
E: The repository 'http://security.ubuntu.com/ubuntu focal-security InRelease' is not signed.
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/focal-security/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal-updates/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'http://archive.ubuntu.com/ubuntu focal-updates InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal-backports/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'http://archive.ubuntu.com/ubuntu focal-backports InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

I found a StackOverflow question on this topic, I have the impression that the answer of Subhash Kumar might be simple and correct, but I have no idea how to do this. (The other answers consist of downloading and installing something from a URL, called "playonlinux", which does not sound very trustworthy)

Next edit: content of /etc/apt/sources.list

This is how my /etc/apt/sources.list looks like. What does the Vanilla one look like?

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu/ focal main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ focal main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu/ focal-updates main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ focal-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ focal universe
# deb-src http://archive.ubuntu.com/ubuntu/ focal universe
deb http://archive.ubuntu.com/ubuntu/ focal-updates universe
# deb-src http://archive.ubuntu.com/ubuntu/ focal-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://archive.ubuntu.com/ubuntu/ focal multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ focal multiverse
deb http://archive.ubuntu.com/ubuntu/ focal-updates multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ focal-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu focal partner
# deb-src http://archive.canonical.com/ubuntu focal partner

deb http://security.ubuntu.com/ubuntu/ focal-security main restricted
# deb-src http://security.ubuntu.com/ubuntu/ focal-security main restricted
deb http://security.ubuntu.com/ubuntu/ focal-security universe
# deb-src http://security.ubuntu.com/ubuntu/ focal-security universe
deb http://security.ubuntu.com/ubuntu/ focal-security multiverse
# deb-src http://security.ubuntu.com/ubuntu/ focal-security multiverse

Next update: sources.list update and "sudo apt update"
Sources.list now looks as follows:

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu/ focal main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ focal main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu/ focal-updates main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ focal-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ focal universe
# deb-src http://archive.ubuntu.com/ubuntu/ focal universe
deb http://archive.ubuntu.com/ubuntu/ focal-updates universe
# deb-src http://archive.ubuntu.com/ubuntu/ focal-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://archive.ubuntu.com/ubuntu/ focal multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ focal multiverse
deb http://archive.ubuntu.com/ubuntu/ focal-updates multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ focal-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu focal partner
# deb-src http://archive.canonical.com/ubuntu focal partner

deb http://security.ubuntu.com/ubuntu/ focal-security main restricted
# deb-src http://security.ubuntu.com/ubuntu/ focal-security main restricted
deb http://security.ubuntu.com/ubuntu/ focal-security universe
# deb-src http://security.ubuntu.com/ubuntu/ focal-security universe
deb http://security.ubuntu.com/ubuntu/ focal-security multiverse
# deb-src http://security.ubuntu.com/ubuntu/ focal-security multiverse

# Added: SuperUser URL : superuser.com/questions/1671403
deb http://it.archive.ubuntu.com/ubuntu/ focal main universe restricted multiverse
deb-src http://it.archive.ubuntu.com/ubuntu/ focal main universe restricted multiverse

deb http://security.ubuntu.com/ubuntu focal-security main universe restricted multiverse
deb-src http://security.ubuntu.com/ubuntu focal-security main universe restricted multiverse

deb http://it.archive.ubuntu.com/ubuntu/ focal-updates main universe restricted multiverse
deb-src http://it.archive.ubuntu.com/ubuntu/ focal-updates main universe restricted multiverse
# Finished adding from SuperUser

Launching sudo apt update yields following results:

[sudo] password for <username>:
Get:1 http://archive.ubuntu.com/ubuntu focal InRelease
Err:1 http://archive.ubuntu.com/ubuntu focal InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:2 http://it.archive.ubuntu.com/ubuntu focal InRelease
Err:2 http://it.archive.ubuntu.com/ubuntu focal InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:3 http://security.ubuntu.com/ubuntu focal-security InRelease
Err:3 http://security.ubuntu.com/ubuntu focal-security InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:4 http://archive.ubuntu.com/ubuntu focal-updates InRelease
Err:4 http://archive.ubuntu.com/ubuntu focal-updates InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:5 http://it.archive.ubuntu.com/ubuntu focal-updates InRelease
Err:5 http://it.archive.ubuntu.com/ubuntu focal-updates InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:6 http://archive.ubuntu.com/ubuntu focal-backports InRelease
Err:6 http://archive.ubuntu.com/ubuntu focal-backports InRelease
  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Reading package lists... Done
N: See apt-secure(8) manpage for repository creation and user configuration details.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
E: The repository 'http://archive.ubuntu.com/ubuntu focal InRelease' is not signed.
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
N: See apt-secure(8) manpage for repository creation and user configuration details.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
E: The repository 'http://it.archive.ubuntu.com/ubuntu focal InRelease' is not signed.
E: Failed to fetch http://it.archive.ubuntu.com/ubuntu/dists/focal/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
N: See apt-secure(8) manpage for repository creation and user configuration details.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
E: The repository 'http://security.ubuntu.com/ubuntu focal-security InRelease' is not signed.
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/focal-security/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
N: See apt-secure(8) manpage for repository creation and user configuration details.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
E: The repository 'http://archive.ubuntu.com/ubuntu focal-updates InRelease' is not signed.
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal-updates/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: Failed to fetch http://it.archive.ubuntu.com/ubuntu/dists/focal-updates/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'http://it.archive.ubuntu.com/ubuntu focal-updates InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal-backports/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'http://archive.ubuntu.com/ubuntu focal-backports InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target CNF (main/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target CNF (main/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target Packages (universe/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:46 and /etc/apt/sources.list:55
W: Target Packages (universe/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:46 and /etc/apt/sources.list:55
W: Target Translations (universe/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:46 and /etc/apt/sources.list:55
W: Target CNF (universe/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:46 and /etc/apt/sources.list:55
W: Target CNF (universe/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:46 and /etc/apt/sources.list:55
W: Target Packages (restricted/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target Packages (restricted/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target Translations (restricted/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target CNF (restricted/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target CNF (restricted/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:44 and /etc/apt/sources.list:55
W: Target Packages (multiverse/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:48 and /etc/apt/sources.list:55
W: Target Packages (multiverse/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:48 and /etc/apt/sources.list:55
W: Target Translations (multiverse/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:48 and /etc/apt/sources.list:55
W: Target CNF (multiverse/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:48 and /etc/apt/sources.list:55
W: Target CNF (multiverse/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:48 and /etc/apt/sources.list:55

This is essentially basic Ubuntu usage, but let's give it a go:

When I want to install new tools or programs, I use apt install but this seems not to work

You have to update your local package repository cache first using:

sudo apt-get update

After that, your apt install will work.


As far as the first is concerned, this command gives no results

It could very well not give any results. It doesn't on my WSL either.

So, where's the /var/adm/messages of my WSL?

/var/adm/messages has gone the way of the dodo since systemd was introduced. journalctl is the new way to retrieve system and application logs.