Il faut corriger ton fichier Sources.list, car il y a un léger problème.
Édites le depuis le terminal, avec :
sudo nano /etc/apt/sources.list
Tu effaces la totalité des lignes pour y remettre ce qui suit :
# deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://fr.archive.ubuntu.com/ubuntu/ bionic main restricted
# deb-src http://fr.archive.ubuntu.com/ubuntu/ bionic main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://fr.archive.ubuntu.com/ubuntu/ bionic-updates main restricted
# deb-src http://fr.archive.ubuntu.com/ubuntu/ bionic-updates main restricted
## 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
## universe WILL NOT receive any review or updates from the Ubuntu security
## team.
deb http://fr.archive.ubuntu.com/ubuntu/ bionic universe
# deb-src http://fr.archive.ubuntu.com/ubuntu/ bionic universe
deb http://fr.archive.ubuntu.com/ubuntu/ bionic-updates universe
# deb-src http://fr.archive.ubuntu.com/ubuntu/ bionic-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://fr.archive.ubuntu.com/ubuntu/ bionic multiverse
# deb-src http://fr.archive.ubuntu.com/ubuntu/ bionic multiverse
deb http://fr.archive.ubuntu.com/ubuntu/ bionic-updates multiverse
# deb-src http://fr.archive.ubuntu.com/ubuntu/ bionic-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://fr.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
# deb-src http://fr.archive.ubuntu.com/ubuntu/ bionic-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 bionic partner
deb-src http://archive.canonical.com/ubuntu bionic partner
deb https://dl.winehq.org/wine-builds/ubuntu/ bionic main
# deb-src https://dl.winehq.org/wine-builds/ubuntu/ bionic main
Le fonctionnement de Nano est assez simple. Les fonctions sont indiquées en bas de page.
N'oublie pas d'enregistrer avec CTRL+o et quitte avec CTRL+x.
Une fois le Sources.list modifié, passe de nouveau ce qui suit :
sudo apt update
sudo apt full-upgrade
Et pour la commande qui a renvoyé une erreur :
lsb_release -a