我只想vestacp在我的 Ubuntu 16.04 上使用安装curl，所以需要我curl通过
apt-get install curl
但它给了我这个错误：
root@cindyadonia:/# apt-get install curl
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package curl 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 'curl' has no installation candidate
我已经关注该帖子但它仍然不起作用。 程序“curl”当前未安装
我错过了什么？请告诉我。
这是我的sources.list。我确实添加了一些我不太明白的#。请纠正我。
# deb cdrom:[Ubuntu-Server 16.04.4 LTS _Xenial Xerus_ - Release amd64 (20180228)]/ xenial main r$
# deb cdrom:[Ubuntu-Server 16.04.4 LTS _Xenial Xerus_ - Release amd64 (20180228)]/ xenial main r$
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
# deb http://archive.ubuntu.com/ubuntu/ xenial main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ xenial main restricted
## Major bug fix updates produced after the final release of the
## distribution.
# deb http://archive.ubuntu.com/ubuntu/ xenial-updates main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ xenial-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
# deb http://archive.ubuntu.com/ubuntu/ xenial universe
# deb-src http://archive.ubuntu.com/ubuntu/ xenial universe
# deb http://archive.ubuntu.com/ubuntu/ xenial-updates universe
# deb-src http://archive.ubuntu.com/ubuntu/ xenial-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
# deb http://archive.ubuntu.com/ubuntu/ xenial multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ xenial multiverse
# deb http://archive.ubuntu.com/ubuntu/ xenial-updates multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ xenial-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
# deb http://archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu xenial partner
# deb-src http://archive.canonical.com/ubuntu xenial partner
# deb http://security.ubuntu.com/ubuntu xenial-security main restricted
# deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted
# deb http://security.ubuntu.com/ubuntu xenial-security universe
# deb-src http://security.ubuntu.com/ubuntu xenial-security universe
# deb http://security.ubuntu.com/ubuntu xenial-security multiverse
# deb-src http://security.ubuntu.com/ubuntu xenial-security multiverse
# deb http://archive.ubuntu.com/ubuntu xenial main universe multiverse restricted
# deb http://archive.ubuntu.com/ubuntu trusty universe
答案1
请用此文件替换您的sources.list文件。我取消注释了所有推荐的存储库（xenial、xenial-updates 和 xenial-security 中的 main/restricted/universe/multiverse；没有反向移植、没有合作伙伴、没有来源），并删除了一些不必要的行：
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu/ xenial main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ xenial main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu/ xenial-updates main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ xenial-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ xenial universe
# deb-src http://archive.ubuntu.com/ubuntu/ xenial universe
deb http://archive.ubuntu.com/ubuntu/ xenial-updates universe
# deb-src http://archive.ubuntu.com/ubuntu/ xenial-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://archive.ubuntu.com/ubuntu/ xenial multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ xenial multiverse
deb http://archive.ubuntu.com/ubuntu/ xenial-updates multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ xenial-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
# deb http://archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu xenial partner
# deb-src http://archive.canonical.com/ubuntu xenial partner
deb http://security.ubuntu.com/ubuntu xenial-security main restricted
# deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted
deb http://security.ubuntu.com/ubuntu xenial-security universe
# deb-src http://security.ubuntu.com/ubuntu xenial-security universe
deb http://security.ubuntu.com/ubuntu xenial-security multiverse
# deb-src http://security.ubuntu.com/ubuntu xenial-security multiverse
之后，使用以下命令下载软件包列表：
sudo apt update
现在，由于您已暂时禁用软件包更新，让我们先将您的系统更新到最新版本：
sudo apt upgrade
此后，curl按您最初打算的方式进行安装：
sudo apt install curl