====== Fedora preinstall ======
===== Backup installed software list =====
  * http://www.cyberciti.biz/tips/linux-get-list-installed-software-reinstallation-restore.html

    dnf list installed > fedoraxx_list_installed

**Manually installed package:**
  * https://ask.fedoraproject.org/en/question/75855/find-manually-installed-packages-by-dnf/
    
Have you already discovered the command sudo dnf history? You can use it to access a database with all previous transaction. Each transaction has an ID number (first column).

The history command knows the following sub-commands: list, info, redo, undo, rollback, userinstalled

Now, you can get a list of all user-installed packages.: 
    sudo dnf history userinstalled.

You can also list all changes of a transaction: 
    sudo dnf history list <i>
    #, ie sudo dnf history list 1,

or get more info about the packages of a certain transaction:
    sudo dnf history info <i>
    #, ie sudo dnf history info 4

To undo a complete transaction, you do: sudo dnf history undo <i>.

For more details about dnf type man dnf or dnf --help in your terminal. There is plenty more you can do with dnf...

===== Install packages from list =====
I created a list of all packages on my F21 system with:

    rpm -qa --qf "%{NAME}.%{ARCH}\n" | sort > Packages.LST

After a clean install of F22, I tried to reinstall all those packages with:

    dnf -y install $(cat Packages.LST)

This used to work fine with Yum, but DNF fails and exits with an error when it tries to install a package that does not exist in the F22 repos. This appears to be a "feature" of DNF.

Dnf and yum will quit if a package member is not present. The rules are ALL or nothing.
I posted a script that I used to download groups. Take a look at it and modify it to your needs. I have it running for packages. If one package fails to exist, it still keeps on going.

==== Working ====

I turn the list into a bash script.
add
    #! /bin/bash
    sudo dnf install #to the front of each line.

You can use an editor like gedit to change all line ends, to line ed sudo dnf install. Copy a lineend into the input column. Extra junk on the copy just delete down to the lineend

    chmod 774 your-script-name

    ./your-script-name

multiple installs are ok. They will be ignored.

==== Better ====
In Console:
    rpm -qa > /backup/installed-software.log
    for i in $(cat /backup/installed-software.log) ; do packages+="$i " ; done
    yum install $packages