build a non-default installed package list for immigration

Before a debian user changes to a new machine, it is better to build a list in which all non-automatically installed packages are list:

$ aptitude -F %p search '~i!~M'

When the user landed on the new box, he or she may write a script to install all needed packages based on the list.

About the search pattern, please see the section in aptitude manual: search pattern.