当我更新我的 ubuntu 时，我收到了一些长行错误和警告消息，还有一些 ppa 无法像 nodejs 那样更新。
youngjinkim@vm-youngjinkim:~$ sudo apt-get update
Hit:1 http://security.ubuntu.com/ubuntu bionic-security InRelease
Hit:2 http://kr.archive.ubuntu.com/ubuntu bionic InRelease
Hit:3 http://kr.archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:4 http://kr.archive.ubuntu.com/ubuntu bionic-backports InRelease
Ign:5 http://repos.azulsystems.com/ubuntu stable InRelease
Get:6 http://repos.azulsystems.com/ubuntu stable Release [8604 B]
Get:7 http://repos.azulsystems.com/ubuntu stable Release.gpg [819 B]
Ign:8 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:9 http://dl.google.com/linux/chrome/deb stable Release
Hit:10 https://packages.microsoft.com/repos/vscode stable InRelease
Hit:11 http://ppa.launchpad.net/ansible/ansible/ubuntu bionic InRelease
Ign:7 http://repos.azulsystems.com/ubuntu stable Release.gpg
Ign:13 http://ppa.launchpad.net/docky-core/stable/ubuntu bionic InRelease
Hit:14 http://ppa.launchpad.net/noobslab/icons/ubuntu bionic InRelease
Hit:15 http://ppa.launchpad.net/noobslab/themes/ubuntu bionic InRelease
Err:16 http://ppa.launchpad.net/docky-core/stable/ubuntu bionic Release
404 Not Found [IP: 172.30.252.31 8080]
Reading package lists... Done
W: GPG error: http://repos.azulsystems.com/ubuntu stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B1998361219BD9C9
E: The repository 'http://repos.azulsystems.com/ubuntu stable Release' 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:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target DEP-11-icons-small (main/dep11/icons-48x48.tar) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target CNF (main/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target CNF (main/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
E: The repository 'http://ppa.launchpad.net/docky-core/stable/ubuntu bionic Release' does not have a Release file.
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:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target DEP-11-icons-small (main/dep11/icons-48x48.tar) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target CNF (main/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
W: Target CNF (main/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list.d/vscode.list:3
我想更新 nodejs 缓存策略，但是当我进行更新时，我收到此消息，然后我检查了 nodsjs ppa 版本为 8，所以我无法安装最新版本的 nodejs。
我承认W：警告，E：错误，但N是什么？
我通过以下方式解决问题
-
步骤 1：安装 VIM
$ sudo apt-get install vim -
步骤2：输入错误的源列表，例如：
$ sudo vim /etc/apt/sources.list - 步骤3：在错误上注释该行，问题将得到解决。