HEAD~ vs HEAD^ vs HEAD@{} also known as tilde vs caret vs at sign

Question

HEAD is a pointer at the current branch. I have seen a variety of notations for ancestors of HEAD including

• HEAD~2
• HEAD^2

Answer 1

git reference suffixes (^N, ~N, @{...})

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.

src