Git caret and tilde

I spent a little bit of time playing with Git today, specifically the way that the ^ (caret) and ~ (tilde) work and thought I'd document it here in case I forget.

The short version

If you want a deeper explanation skip down to "The long version".

ref~ is shorthand for ref~1 and means the commit's first parent. ref~2 means the commit's first parent's first parent. ref~3 means the commit's first parent's first parent's first parent. And so on.

ref^ is shorthand for ref^1 and means the commit's first parent. But where the two differ is that ref^2 means the commit's second parent (remember, commits can have two parents when they are a merge).

The ^ and ~ operators can be combined.

Here's a diagram showing how to reference various commits using HEAD as the starting point.