Xubuntu 18.04/64 bit
Synaptic informuje mnie o:
W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target Packages (main/binary-i386/Packages) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target Translations (main/i18n/Translation-pl_PL) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target Translations (main/i18n/Translation-pl) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target DEP-11-icons-small (main/dep11/icons-48x48.tar) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target CNF (main/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target CNF (main/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list.d/vivaldi.list:3
W: Target Packages (non-free/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target Packages (non-free/binary-i386/Packages) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target Packages (non-free/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target Translations (non-free/i18n/Translation-pl_PL) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target Translations (non-free/i18n/Translation-pl) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target Translations (non-free/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target DEP-11 (non-free/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target DEP-11 (non-free/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target DEP-11-icons-small (non-free/dep11/icons-48x48.tar) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target DEP-11-icons (non-free/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target CNF (non-free/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
W: Target CNF (non-free/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:54 and /etc/apt/sources.list.d/opera-stable.list:4
O co chodzi i co ja mogę, że system coś gdzieś wielokrotnie konfiguruje?
Chyba chodzi o to, że masz to samo repozytorium dodane w dwóch plikach z repozytoriami, a wystarczy jedno.