Backup sources and setting for reinstall [duplicate]

Possible Duplicate:
Best way to backup all settings, list of installed packages, tweaks, etc?

I currently have Ubuntu 10.10 installed on my laptop. Configured just the way I like it. Now I need to reinstall everything because I have a need to encrypt my whole hard drive and on Ubuntu, that can only be done using the alternate CD. Question is what would be a good way to reinstall everything including sources and PPA's after encryption?

Solution 1:

1. Find some removable medium, e.g. a flash drive.
2. Save /etc/apt/sources.list and every file in /etc/apt/sources.list.d/ to it.
3. Open System > Administration > Synaptic Package Manager. Go to File > Save Markings As... , check the box labeled "Save full state, not only changes", and save it to the removable medium. This file is basically a list of every single package you have installed.

Once you've reinstalled:

1. Restore your /etc/apt/sources.list and contents of /etc/apt/sources.list.d/ to the computer.
2. Open Synaptic again, and press Reload.
3. Still in Synaptic, go to File > Read Markings. Open the markings file you saved previously. Then press Apply, sit back, and relax.