From howtoforge I picked this and modified it to fit my needs.
The commands in this article must be executed with root privileges. Open a terminal (on a Fedora 12 desktop, go to Applications > System Tools > Terminal) and log in as root, or if you log in with a regular user, type
to become root.
Upgrading To Fedora 13
First we must upgrade the rpm package:
yum update rpm
Then we install the latest updates:
yum -y update
Next we clean the yum cache:
yum clean all
If you notice that a new kernel got installed during yum -y update, you should reboot the system now:
After the reboot, log in as root again, either directly or with the help of
Get rid of surplus kernels - the upgrade uses the /boot partition, which is not very large.
package-cleanup --oldkernels yum clean all
Now we come to the upgrade process. We can do this with preupgrade (preupgrade will also take care of your RPMFusion packages).
yum install preupgrade
... and call it like this:
The preupgrade wizard will then start on your desktop. Select Fedora 13 (Goddard). Afterwards the system is being prepared for the upgrade.
At the end, click on the Reboot Now button.
During the reboot, the upgrade is being performed. This can take quite a long time, so please be patient.
Afterwards, you can log into your new Fedora 13 desktop.
Perform this to get the latest, if it wasn't covered in the upgrade process:
su yum update