如何在 Ubuntu 18.04 中安装“Double Commander”或“Midnight Commander”文件管理器？
我试图安装 Midnight Commandersudo apt-get install mc但得到了
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package mc 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 'mc' has no installation candidate
是否有一些适用于 Ubuntu 18.04 的工作文件管理器？