This is a personal collection of useful git commands and tools

https://git-cola.github.io/downloads.html

Install kdiff3 with

sudo apt-get install kdiff3-qt

and then get commit head with

git log

and now you can run for example

git difftool 4fb7737350cc0b646177cb0a041fc73422ffc98a main.c

DeepGit could be an interesting tool: https://www.syntevo.com/deepgit/