I have a 32-bit installation of 11.10 on my 64-bit (4 GB) home AMD system. I have recently read up a bit on 64-bit version, and it seems that it would be a marginally better choice now for me.

I have read about several methods to help reinstall all the various apps, using either dpkg's get-selections/set-selections and dselect in various ways, or using synaptic's save/get markings.

The problem here is that I've read several variations, and I'm not sure which is best. I have enough disk space to do this with a brand new partition, so I'm not too worried about destroying anything, but I don't really want to make it my life's work, hence my appeal for expert tips.

Since it's the same version, would it be safe to copy configuration files from the 32-bit system? I'd guess my home directory and /etc might be enough, and would save at least most of the time to reconfigure. But are there difference in configuration files in either of these directories for 32 vs 64 bits that might cause problems?

After reinstalling to 64-bit, I can then continue along the 64 bit path for upgrades, but I thought it would be easier to switch the same version, than to try to reinstall apps and upgrade at the same time.

Some methods I've seen suggested, among others:

A. From Ubuntu forums

On your old system (assuming it is still working), start up Synaptic and go:

File->Save Markings and choose a file name along with a location (like a USB drive) that you can use when you have installed your new system). You need to check on the bottom: "Save full state, not only changes"

This file contains a list of all your currently installed packages, and when you have installed and booted up your new system (and configured your repositories to the best for your location - as we all do, don't we?) then start up Synaptic and go:

File-Read Markings and point it at your saved file, and after that has completed then select Apply to kick off the download & installation of all of those packages you had installed previously!

B. From the same discussion:

According to section 6.4.9 of the Debian Reference Manual, the following will save both the list of packages installed and their debconf configuration:

# dpkg --get-selections "*" >myselections   # or use \*
# debconf-get-selections > debconfsel.txt

and the following will reinstall and reconfigure them:

# dselect update
# debconf-set-selections < debconfsel.txt
# dpkg --set-selections <myselections
# apt-get -u dselect-upgrade    # or dselect install

C. A variation on the above I've seen a lot, this from stackoverflow:

dpkg --get-selections > package_list

then on the new install:

cat package_list | sudo dpkg --set-selections && sudo apt-get dselect-upgrade

I don't really understand B, or why it's slightly different than many others.