If you use Arch Linux, you’ve probably noticed that after a while, and especially after system updates, files with the .pacnew extension start showing up on your system. And since you’re reading this, that’s likely what brought you here: to figure out what these files are, why they appear, and what you’re supposed to do with them.
Well, you’ve come to the right place. In the lines below, I’ll try to explain everything clearly and straightforwardly. So, let’s start with the main question.
I’ve never seen anything beat Gentoo’s interactive diff and merge of config files. That’s the only thing I miss from Gentoo and I have no ideas why other distributions haven’t picked that up. It’s perfect.