setfacl/getfacl 命令未在我的服务器上运行，它显示：
The program 'setfacl' is currently not installed. You can install it by typing:
sudo apt-get install acl
当我尝试安装它时，它显示：
sudo apt-get install acl
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package acl 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 'acl' has no installation candidate
答案1
我在 apt 配置源列表中添加了以下源代码行：
deb http://cz.archive.ubuntu.com/ubuntu trusty main
然后我就可以正常安装acl了。