我正在使用fabric处理部署，一步是升级debian软件包。我正在执行
sudo('aptitude install packagename')
它会问我：
[server] out: 1 packages upgraded, 0 newly installed, 0 to remove and 110 not upgraded.
[server] out: Need to get 40.7 kB of archives. After unpacking 1,024 B will be used.
[server] out: Do you want to continue? [Y/n/?]
我想确保正好有1个包升级，0个要删除。我正在尝试解析基于该规则的问题，但我无法弄清楚如何在命令执行完之前访问该文本。有办法吗？