我的软件包和存储库出现了一些问题，因此我决定尝试重置文件sources.list。我通过从命令行中删除它、在其位置创建一个空白文件，然后使用 Ubuntu 的软件和更新 GUI 尝试重新制作它来做到这一点。然而，这似乎带来了新的问题。当我尝试运行时sudo apt-get update，我得到了以下输出：
Get:1 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Hit:2 http://us.archive.ubuntu.com/ubuntu bionic InRelease
Hit:3 https://brave-browser-apt-release.s3.brave.com bionic InRelease
Hit:4 http://packages.microsoft.com/repos/vscode stable InRelease
Get:5 http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Hit:6 http://repo.steampowered.com/steam precise InRelease
Ign:7 http://ppa.launchpad.net/mc3man/trusty-media/ubuntu bionic InRelease
Hit:8 https://download.sublimetext.com apt/stable/ InRelease
Hit:9 http://ppa.launchpad.net/papirus/papirus/ubuntu bionic InRelease
Get:10 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages [260 kB]
Get:11 http://us.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages [517 kB]
Hit:12 http://ppa.launchpad.net/plushuang-tw/uget-stable/ubuntu bionic InRelease
Get:13 http://security.ubuntu.com/ubuntu bionic-security/main i386 Packages [197 kB]
Get:14 http://security.ubuntu.com/ubuntu bionic-security/main Translation-en [97.6 kB]
Get:15 http://us.archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages [446 kB]
Err:16 http://ppa.launchpad.net/mc3man/trusty-media/ubuntu bionic Release
404 Not Found [IP: 91.189.95.83 80]
Get:17 http://us.archive.ubuntu.com/ubuntu bionic-updates/main Translation-en [193 kB]
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/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.
我不太清楚这里的问题是什么。我的目标是将存储库列表重置为出厂默认设置，以确保稳定性，并在必要时重新添加内容，但似乎默认配置效果不佳。
答案1
这不是默认配置。看来你没有清除 中的源列表/etc/apt/sources.list.d/。