我曾经将contrib&添加non-free到我的 apt 源中，但发现它们从 jammy 中消失了：
$ sudo apt update
W: Skipping acquire of configured file 'contrib/binary-amd64/Packages' as repository 'http://archive.ubuntu.com/ubuntu jammy InRelease' doesn't have the component 'contrib' (component misspelt in sources.list?)
W: Skipping acquire of configured file 'non-free/binary-amd64/Packages' as repository 'http://archive.ubuntu.com/ubuntu jammy InRelease' doesn't have the component 'non-free' (component misspelt in sources.list?)
W: Skipping acquire of configured file 'contrib/binary-amd64/Packages' as repository 'http://archive.ubuntu.com/ubuntu jammy-updates InRelease' doesn't have the component 'contrib' (component misspelt in sources.list?)
W: Skipping acquire of configured file 'non-free/binary-amd64/Packages' as repository 'http://archive.ubuntu.com/ubuntu jammy-updates InRelease' doesn't have the component 'non-free' (component misspelt in sources.list?)
然后，如何解决常见问题，例如：
E: Package 'rar' has no installation candidate
E: Package 'unrar' has no installation candidate
$ cat /etc/apt/sources.list
deb http://archive.ubuntu.com/ubuntu/ jammy main contrib non-free restricted universe
deb http://security.ubuntu.com/ubuntu/ jammy-security main restricted universe
deb http://archive.ubuntu.com/ubuntu/ jammy-updates main contrib non-free restricted universe
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 22.04.1 LTS
Release: 22.04
Codename: jammy
答案1
rar和unrar软件包可从multiverse存储库获取。如果是常规 Ubuntu 版本，则默认启用此功能。
contrib并且non-free不是 Ubuntu 存储库，而是 Debian。