apt error

通过 ppa 增加某个源的时候,执行:
$ sudo add-apt-repository ppa:xxx
会出现如下的 error:
sudo: add-apt-repository: command not found

原因是缺少 python-software-properties,安装即可:
$ sudo apt-get install python-software-properties

ref:
http://pricklytech.wordpress.com/2011/07/24/ubuntu-server-10-4-lucid-add-apt-repository-command-not-found/