Here is the situation: say, at 17:00, I installed a lot of packages, I can see them in the ubuntu software center history. Also I can see them in the dpkg log file using the method provided by [this](https://askubuntu.com/questions/50622/how-to-reinstall-many-removed-packages-at-once) thread. My question is: how can I delete them easily. There are so many, I can't delete them one by one in synaptic.

The thread I linded may have explain the method. However, I can't see the time specified in the command, for I don't want delete any other packages installed at other time.