Show one commit in difftool

Imagine you want to review one old commit side by side in a GUI diff tool.

Usually I start with git show 8d73caed in the terminal.

If you want a side-by-side view, use git difftool with the commit and its parent:

git difftool 8d73caed^ 8d73caed

^ means "the parent commit of 8d73caed".

This launches meld if it is installed, or your preferred diff tool. See git-difftool.