我注意到我的一些软件包已经过期，而 apt 声称它们是最新版本。当我运行 时apt-get update，我得到了：
sudo apt-get update
Ign:1 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:2 http://repository.spotify.com stable InRelease
Hit:3 http://archive.ubuntu.com/ubuntu bionic InRelease
Ign:4 http://ppa.launchpad.net/b-eltzner/qpdfview/ubuntu bionic InRelease
Hit:5 http://archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:6 http://dl.google.com/linux/chrome/deb stable Release
Ign:7 http://ppa.launchpad.net/george-edison55/cmake-3.x/ubuntu bionic InRelease
Hit:8 http://archive.ubuntu.com/ubuntu bionic-backports InRelease
Hit:9 https://packages.microsoft.com/repos/vscode stable InRelease
Hit:10 http://archive.ubuntu.com/ubuntu bionic-security InRelease
Ign:11 http://ppa.launchpad.net/libreoffice/libreoffice-4-2/ubuntu bionic InRelease
Hit:12 http://ppa.launchpad.net/libreoffice/ppa/ubuntu bionic InRelease
Hit:13 http://ppa.launchpad.net/nilarimogard/webupd8/ubuntu bionic InRelease
Ign:14 http://ppa.launchpad.net/tigerite/kernel/ubuntu bionic InRelease
Err:15 http://ppa.launchpad.net/b-eltzner/qpdfview/ubuntu bionic Release
404 Not Found [IP: 91.189.95.83 80]
Err:16 http://ppa.launchpad.net/george-edison55/cmake-3.x/ubuntu bionic Release
404 Not Found [IP: 91.189.95.83 80]
Err:17 http://ppa.launchpad.net/libreoffice/libreoffice-4-2/ubuntu bionic Release
404 Not Found [IP: 91.189.95.83 80]
Err:18 http://ppa.launchpad.net/tigerite/kernel/ubuntu bionic Release
404 Not Found [IP: 91.189.95.83 80]
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/b-eltzner/qpdfview/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.
E: The repository 'http://ppa.launchpad.net/george-edison55/cmake-3.x/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.
E: The repository 'http://ppa.launchpad.net/libreoffice/libreoffice-4-2/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.
E: The repository 'http://ppa.launchpad.net/tigerite/kernel/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.
我尝试切换到不同的来源，运行并将--allow-unauthenticatedsources.list[trusted=yes]中的所有内容放在前面。有什么想法吗？我的 sources.list 文件是：
# deb cdrom:[Ubuntu 18.04.1 LTS _Bionic Beaver_ - Release amd64 (20180725)]/ bionic main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu bionic main
deb-src http://archive.ubuntu.com/ubuntu bionic main
deb http://archive.ubuntu.com/ubuntu bionic restricted
# deb-src http://de.archive.ubuntu.com/ubuntu/ bionic main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu bionic-updates main restricted
# deb-src http://de.archive.ubuntu.com/ubuntu/ bionic-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 bionic universe
# deb-src http://de.archive.ubuntu.com/ubuntu/ bionic universe
deb http://archive.ubuntu.com/ubuntu bionic-updates universe
# deb-src http://de.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://archive.ubuntu.com/ubuntu bionic multiverse
# deb-src http://de.archive.ubuntu.com/ubuntu/ bionic multiverse
deb http://archive.ubuntu.com/ubuntu bionic-updates multiverse
# deb-src http://de.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 [trusted=yes] http://archive.ubuntu.com/ubuntu bionic-backports main restricted universe multiverse
# deb-src http://de.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 http://archive.ubuntu.com/ubuntu bionic-security main restricted
# deb-src http://security.ubuntu.com/ubuntu bionic-security main restricted
deb http://archive.ubuntu.com/ubuntu bionic-security universe
# deb-src http://security.ubuntu.com/ubuntu bionic-security universe
deb http://archive.ubuntu.com/ubuntu bionic-security multiverse
# deb-src http://security.ubuntu.com/ubuntu bionic-security multiverse
答案1
你为什么不直接开放软件和资源呢：
并取消勾选所有有问题的来源，
然后关闭软件和源（让它重新加载源）
并再次尝试更新。
您不想使用与您的发行版不匹配的源。首先修复更新，然后逐个添加为您的发行版制作的 PPA 版本，并检查它们不会破坏每个更新。