Reinstall Ubuntu without losing your data

I can't remember where I learned this but I use it whenever I need to reinstall Ubuntu on my machines, or when I am doing a fresh install on a new machine.
What this does is very simple. The first step creates a text file with a list of installed programs and after reinstalling Ubuntu you will be able to apply that list and reinstall all of the programs without searching through endless amounts of packages trying to find out what programs you are missing.

Pros:

Very easy to do. Just three commands and you are back up and running. Not much interaction from the user.It just works.

Cons:
Requires some initial setup. Depending on the amount of applications you originally had installed, downloading and installing those packages may take some time.


Prerequisites:
Your 'home' folder must be on a separate partition. I will explain later in this article.


Let's get started.

The first step you will have to do is create a text file.
Go to 'Applications>Accessories>Terminal'
Type in the terminal

sudo dpkg --get-selections > backup.log

You will be required to provide your user password.
Now you have created a text file in your home directory. Keep this file somewhere safe. Maybe a thumb drive or something. Or you could email it to your yahoo or gmail account.
You also have a very small backup of your installed programs.
This will not backup any of your files. ie - photos, documents,videos, etc. Standard backup practices apply to those types of files.


Next you can take this file to any computer running Ubuntu and all of those applications.
If now is the time, reinstall Ubuntu and make sure that after the install you have that 'backup.log' file in your home directory.
Now you can apply that to a list of programs to download and install.
First you will have to make sure that all of your repositories are enabled that you originally downloaded the software from. If you added sources to your sources.list file, then you will have to do that now before you go on.
If you haven't added any repositories, then you are ok to continue.
Next you will have to go back to a terminal and type

sudo dpkg --set-selections < backup.log

Supply your password if asked.

The next step requires a package that is not installed by default in Ubuntu.
To install the program, type in the terminal


sudo apt-get install dselect

Supply your password if asked.

Now all that is left is to type one last command into the terminal.
Now type


sudo dselect

Supply your password if asked.

Now select 'install'

Now you can walk away, make a beverage and come back to check on it once in a while.
You may have to click 'next' or 'ok'.
Once it is finished you can exit.
Now you are finished and you can use all of the programs you were using before we started this procedure.


Notes:

The reason for having your home folder on a seperate partition is because of the hidden files and folders in your home folder. All of your program's settings are stored in your home folder.
For example: all of your bookmarks, extensions and browsing history in firefox are stored in there as well as your desktop wallpaper and all of your settings. Once the programs are all installed they will still have the same settings as they did before. If you are a former windows user and have had to reinstall the OS, then you know that it can take many hours to set windows up the way it used to be. Not with linux. If you want to install a dual boot system with Fedora and Ubuntu, just make sure that both of the installs use the same home folder. That way both of your desktop settings will be the same.



Enjoy!