Bonjour,
Merci beaucoup pour votre aide, voici les réponses du terminal suite aux commandes indiquées ci-dessus :
blaise@blaise-w65-w67rz1:~$ cat /etc/issue
Ubuntu 20.04.1 LTS \n \l
blaise@blaise-w65-w67rz1:~$ uname -a
Linux blaise-w65-w67rz1 5.4.0-52-generic #57-Ubuntu SMP Thu Oct 15 10:57:00 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
blaise@blaise-w65-w67rz1:~$ echo "${XDG_CURRENT_DESKTOP}"
Unity:Unity7:ubuntu
blaise@blaise-w65-w67rz1:~$ find /etc/apt -name '*.list' -exec bash -c 'echo -e "\n$1\n"; nl -ba "$1"' _ '{}' \;
/etc/apt/sources.list
1 # deb cdrom:[Ubuntu 16.04.2 LTS _Xenial Xerus_ - Release amd64 (20170215.2)]/ xenial main restricted
2
3 # See
http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
4 # newer versions of the distribution.
5 deb
http://fr.archive.ubuntu.com/ubuntu/ focal main restricted
6 deb-src
http://fr.archive.ubuntu.com/ubuntu/ xenial main restricted
7
8 ## Major bug fix updates produced after the final release of the
9 ## distribution.
10 deb
http://fr.archive.ubuntu.com/ubuntu/ focal-updates restricted main
11 deb-src
http://fr.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
12
13 ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
14 ## team. Also, please note that software in universe WILL NOT receive any
15 ## review or updates from the Ubuntu security team.
16 deb
http://fr.archive.ubuntu.com/ubuntu/ focal universe
17 deb-src
http://fr.archive.ubuntu.com/ubuntu/ xenial universe
18 deb
http://fr.archive.ubuntu.com/ubuntu/ focal-updates universe
19 deb-src
http://fr.archive.ubuntu.com/ubuntu/ xenial-updates universe
20
21 ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
22 ## team, and may not be under a free licence. Please satisfy yourself as to
23 ## your rights to use the software. Also, please note that software in
24 ## multiverse WILL NOT receive any review or updates from the Ubuntu
25 ## security team.
26 deb
http://fr.archive.ubuntu.com/ubuntu/ focal multiverse
27 deb-src
http://fr.archive.ubuntu.com/ubuntu/ xenial multiverse
28 deb
http://fr.archive.ubuntu.com/ubuntu/ focal-updates multiverse
29 deb-src
http://fr.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
30
31 ## N.B. software from this repository may not have been tested as
32 ## extensively as that contained in the main release, although it includes
33 ## newer versions of some applications which may provide useful features.
34 ## Also, please note that software in backports WILL NOT receive any review
35 ## or updates from the Ubuntu security team.
36 deb-src
http://fr.archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
37
38 ## Uncomment the following two lines to add software from Canonical's
39 ## 'partner' repository.
40 ## This software is not part of Ubuntu, but is offered by Canonical and the
41 ## respective vendors as a service to Ubuntu users.
42 # deb
http://archive.canonical.com/ubuntu xenial partner
43 deb-src
http://archive.canonical.com/ubuntu xenial partner
44
45 deb
http://security.ubuntu.com/ubuntu focal-security restricted main
46 deb-src
http://security.ubuntu.com/ubuntu xenial-security main restricted
47 deb
http://security.ubuntu.com/ubuntu focal-security universe
48 deb-src
http://security.ubuntu.com/ubuntu xenial-security universe
49 deb
http://security.ubuntu.com/ubuntu focal-security multiverse
50 deb-src
http://security.ubuntu.com/ubuntu xenial-security multiverse
/etc/apt/sources.list.d/xenial-partner.list
1 # channel for the xenial (16.04) partner channel
2 #
3 #:description:This channel contains the partner software for xenial
4 # deb
http://archive.canonical.com/ubuntu focal partner
blaise@blaise-w65-w67rz1:~$