Kitchen's questions

我正在使用 Ubuntu 20.04。我从Oracle 网站下载了适用于 Ubuntu 19.10 / 20.04 的 VirtualBox ，然后dpkg -i virtualbox-6.1_6.1.16-140961~Ubuntu~eoan_amd64.deb在终端中使用：安装它。现在我需要安装缺少的依赖项。

我怎么知道依赖项是安全的？他们来自哪里？它们来自 Ubuntu 官方存储库、VirtualBox 还是第三方？

结果sudo apt-get -f：

Building dependency tree       
Reading state information... Done
Correcting dependencies... Done
The following package was automatically installed and is no longer required:
  libfprint-2-tod1
Use 'sudo apt autoremove' to remove it.
The following additional packages will be installed:
  libdouble-conversion3 libpcre2-16-0 libpython2-stdlib libpython2.7-minimal
  libpython2.7-stdlib libqt5core5a libqt5dbus5 libqt5gui5 libqt5network5
  libqt5opengl5 libqt5printsupport5 libqt5svg5 libqt5widgets5 libqt5x11extras5
  libsdl1.2debian libxcb-xinerama0 libxcb-xinput0 python-is-python2 python2
  python2-minimal python2.7 python2.7-minimal qt5-gtk-platformtheme
  qttranslations5-l10n
Suggested packages:
  qt5-image-formats-plugins qtwayland5 python2-doc python-tk python2.7-doc
  binfmt-support
The following NEW packages will be installed
  libdouble-conversion3 libpcre2-16-0 libpython2-stdlib libpython2.7-minimal
  libpython2.7-stdlib libqt5core5a libqt5dbus5 libqt5gui5 libqt5network5
  libqt5opengl5 libqt5printsupport5 libqt5svg5 libqt5widgets5 libqt5x11extras5
  libsdl1.2debian libxcb-xinerama0 libxcb-xinput0 python-is-python2 python2
  python2-minimal python2.7 python2.7-minimal qt5-gtk-platformtheme
  qttranslations5-l10n
0 to upgrade, 24 to newly install, 0 to remove and 0 not to upgrade.
1 not fully installed or removed.
Need to get 14.5 MB of archives.
After this operation, 62.2 MB of additional disk space will be used.
Do you want to continue? [Y/n]

编辑：“ 1 not fully installed or removed”是 virtualbox 包本身。我现在已经删除了 virtualbox usingsudo apt-get remove --purge virtualbox并重新安装了 using apt install virtualbox，它已经自动安装了所需的依赖项。我知道这些是安全的，并且来自 Ubuntu 官方存储库，因为我没有启用其他不受支持的第三方存储库（这些选项在软件和更新中心未选中）。

我做了：

sudo ppa-purge ppa:cybermax-dexter/sdl2-backport

并得到：

Updating packages lists
W: The repository 'http://ppa.launchpad.net/cybermax-dexter/sdl2-backport/ubuntu xenial Release' does not have a Release file.
E: Failed to fetch http://ppa.launchpad.net/cybermax-dexter/sdl2-backport/ubuntu/dists/xenial/main/binary-amd64/Packages  404  Not Found [IP: 91.....]
E: Some index files failed to download. They have been ignored, or old ones used instead.
Warning:  apt-get update failed for some reason

当我查看软件和更新-> 其他软件时，PPA 仍然存在，也在sources.list.d文件夹中，但不在sources.list文件中。

我意识到 W: 部分是因为 PPA 与xenial. 但我仍然不明白这两个 E: 部分是什么意思，以及如何清除 PPA。

我可以手动删除，但我想确保我已经清除了所有相关文件等，因为它是第三方，我不希望任何不可靠的东西留在我的电脑上......？顺便说一句，我是菜鸟，所以可能对此有点无知...

谢谢你的时间！