Replicating an installation

[Geoffrey Leach]

My internet service comes over a satellite, and with it a relatively
small monthly download allowance. Which motivates the following
question.

Once I have installed a new disto and downloaded the RPMs that I use, is
there a procedure by which I could gather together everything that I
have added, so that I could transfer the files (RPMs, or whatever) to
a local system, without resorting to the internet? (Or, at least, to a
significant amount!)

Thanks.