Why was Diffuse left out of Universe repository of Ubuntu 20.04? What to use instead (if you don't want to use plain
diff but a graphical software)?
It is possible to install from manually downloaded packages from 18.04 LTS:
cd ~/Downloads wget http://archive.ubuntu.com/ubuntu/pool/universe/p/pygtk/python-gtk2_2.24.0-5.1ubuntu2_amd64.deb wget http://archive.ubuntu.com/ubuntu/pool/universe/d/diffuse/diffuse_0.4.8-3_all.deb sudo apt-get install ./diffuse_0.4.8-3_all.deb ./python-gtk2_2.24.0-5.1ubuntu2_amd64.deb
As of summer 2020, the updated fork of diffuse at https://github.com/MightyCreak/diffuse is the best way to go. It is very usable directly from source on Ubuntu 20.04. The main prerequisites are python3 and python3-gi, both of which are new enough on Ubuntu 20.04. Install python3 and python3-gi with
sudo apt install python3-gi
On non-desktop machines, you may need to install also the following packages that are otherwise typically installed already:
sudo apt install gobject-introspection gir1.2-gtk-3.0 gnome-icon-theme python3-gi-cairo
Then clone the diffuse fork from github to a folder of your liking. To run diffuse, it's sufficient to call the python script
src/usr/bin/diffuse. It may be even more convenient to add the bin-folder to your PATH:
The path setting can also be placed in your shells startup scripts (i.e.
.bashrc or similar) to have diffuse always available.