由于某种原因，我的 ubuntu-software-center 消失了（在 Ubuntu 18.04 上）。
我尝试了通常的
sudo apt-get update
和
sudo apt-get install software-center
但我最终遇到了这个错误：
Package software-center is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'software-center' has no installation candidate
我该如何解决这个问题？我尝试使用突触，但没有成功。
答案1
我认为 Ubuntu 软件中心没有该软件包的名称；当我输入命令时apt search，在结果中没有得到该软件包名称：
$ apt-cache search software-center
app-install-data - Ubuntu applications (data files)
software-center-aptdaemon-plugins - The aptdaemon plugins for software-center
ubuntu-kylin-software-center - Software maintenance management tools
在 Ubuntu 18.04 上，软件中心包被命名为gnome-software（如果你使用 GNOME 桌面）
$ apt-cache search gnome-software
gnome-software - Software Center for GNOME
gnome-software-common - Software Center for GNOME (common files)
gnome-software-dev - Software Center for GNOME - development files
gnome-software-doc - Software Center for GNOME - documentation
gnome-software-plugin-snap - Snap support for GNOME Software
gnome-packagekit-session - Transitional package (gnome-packagekit-session -> gnome-software)
gnome-software-plugin-flatpak - Flatpak support for GNOME Software
gnome-software-plugin-limba - Limba support for GNOME Software
libflatpak0 - Application deployment framework for desktop apps (library)
因此，如果你想重新安装它，只需输入
sudo apt install gnome-software