What is HEAD in Git?
git
Solution
You can think of the HEAD as the "current branch". When you switch branches with `git checkout`, the HEAD revision changes to point to the tip of the new branch.
You can see what HEAD points to by doing:
cat .git/HEAD
In my case, the output is:
$ cat .git/HEAD
ref: refs/heads/master
It is possible for HEAD to refer to a specific revision that is not associated with a branch name. This situation is called a detached HEAD.
Problem
You see the Git documentation saying things like The branch must be fully merged in HEAD. But what is Git `HEAD` exactly?