我正在尝试从 PPA 向 Ubuntu 12.10 添加一些外部包。为此，我需要使用add-apt-repository. 很简单 - add-apt-repository: command not found in Ubuntu 10.04告诉我安装python-software-properties. 我已经做到了 - 这是它已经存在的证据：
user@hostname:~$ sudo apt-get install python-software-properties
Reading package lists... Done
Building dependency tree
Reading state information... Done
python-software-properties is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 58 not upgraded.
然而，我仍然没有add-apt-repository：
user@hostname:~$ sudo add-apt-repository
sudo: add-apt-repository: command not found
user@hostname:~$ add-apt-repository
The program 'add-apt-repository' can be found in the following packages:
* python-software-properties
* software-properties-common
Try: sudo apt-get install <selected package>
我缺少什么（明显的？）东西？
我问完问题后几乎立即找到了它。我需要这两个包 - 我添加了
software-properties-common，我很好。尽管从错误中这对我来说一点也不明显。