Duplicating an Ubuntu machine so you can install Rivendell
From Rivendell Wiki
(Or a Debian Machine)
First you need to create a list of installed packages
sudo dpkg --get-selections > installed-software.txt
And if you wanted to use the list to reinstall this software on a fresh ubuntu setup,
sudo dpkg --set-selections < installed-software.txt
followed by
sudo dselect
In dselect choose the option install this will install everything from your text file
If dselect isn't installed you might have to install it by typing
sudo apt-get install dselect
Hints
To save installation time copy the entire group of previously downloaded deb packages from the /var/cache/apt/archives/
This will save downloading everything again.
Also you want to copy the /etc/apt/sources.list
Don't forget to enter the repository key from Alban's website. (If using Alban's packages)

