I have separate
/home partitions, of which both use ext4 as their filesystem.
How can I merge them, and what is the easiest way?
I don't think there's an easier way. You need to copy the data from one partition to the other. You need to delete the old home partition and resize the root partition. That cannot be done on a running system, so a live CD or USB seems like as good as it gets.
That should be it.
I dont know about the easiest or the best approach but here is how I would do it. I would just create folder in