我无法使用`curl 从网络获取内容。我尝试安装它并得到以下输出：
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies.
curl : Depends: libcurl4 (= 7.58.0-2ubuntu3) but it is not going to be installed
E: Unable to correct problems, you have held broken packages. …我想了解什么是屏蔽服务以及如何在需要时取消屏蔽它。
我一直在尝试使用以下命令在 Ubuntu 16.04-LTS 上启动 PostgreSQL
systemctl start postgresql.service.
分别作为具有管理权限的用户和 root 用户。
不幸的是，我得到了
Failed to start postgresql.service: Unit postgresql.service is masked.
在两种情况下打印。