当输入：sudo apt-get update时，出现以下错误
Hit:1 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:2 http://ppa.launchpad.net/fingerprint/fingerprint-gui/ubuntu focal InRelease
...
Ign:9 http://old-releases.ubuntu.com/ubuntu focal InRelease
Ign:10 http://old-releases.ubuntu.com/ubuntu focal-updates InRelease
Ign:11 http://old-releases.ubuntu.com/ubuntu focal-backports InRelease
Err:12 http://old-releases.ubuntu.com/ubuntu focal Release
404 Not Found [IP: 2001:67c:1562::25 80]
Hit:13 http://packages.ros.org/ros/ubuntu focal InRelease
Err:14 http://old-releases.ubuntu.com/ubuntu focal-updates Release
404 Not Found [IP: 2001:67c:1562::25 80]
Err:15 http://old-releases.ubuntu.com/ubuntu focal-backports Release
404 Not Found [IP: 2001:67c:1562::25 80]
Reading package lists... Done
E: The repository 'http://old-releases.ubuntu.com/ubuntu focal 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://old-releases.ubuntu.com/ubuntu focal-updates 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://old-releases.ubuntu.com/ubuntu focal-backports 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.
我查看过该网站上的其他论坛，但没有一个论坛提供解决此问题的解决方案。
任何帮助，将不胜感激，
扎多尔
答案1
您的来源列表是错误的。正如 guiverc 指出的那样，Focal 不在旧版本中。