HEAD in Git refers to the currently checked out reference in a repository. It is a symbolic reference that points to the latest commit on the current branch. When you make a commit, the
HEAD reference is automatically updated to point to the new commit. The
HEAD reference can be used to switch between branches and restore older versions of a repository. The
HEAD is stored as a file in the
.git directory and can be edited directly to change the current branch or reference.
Git Show Head
git show head command shows information about the current state of the HEAD in the repository. This can be useful when you want to see what changes have been made to the repository, or when you need to confirm that the repository is pointing to the correct branch.
The format of the output will include information about the commit hash, the author, the date and time of the commit, and the commit message. You can also view the changes that were made in each commit by using the
git diff command.
For example, to show information about the current HEAD in the repository, you can run the following command:
$ git show head
This will display information about the most recent commit in the repository, including the commit hash, author, date and time, and commit message.
Git Detached Head
A detached head in Git is a state where the current branch is not attached to a named branch. This means that the branch head is pointing directly to a commit rather than a branch name. This can happen when you checkout a specific commit instead of a branch, or if you create a new branch from a commit.
For example, you may have a repository with the following history:
* 5c6d8a6 (HEAD, master) Commit 5 * c7d9b7f Commit 4 * 8a6c5d7 Commit 3 * b7c9d8f Commit 2 * 6a5c8d7 Commit 1
If you checkout the commit
c7d9b7f, you’ll find yourself in a detached head state:
$ git checkout c7d9b7f Note: checking out 'c7d9b7f'. You are in 'detached HEAD' state. HEAD is now at c7d9b7f... Commit 4
In this state, you can still make changes and create new commits, but they will not be associated with any branch and may be lost when you switch to a different branch. To avoid losing changes, it’s a good idea to create a new branch while in a detached head state.
$ git checkout -b new-branch Switched to a new branch 'new-branch'
This will create a new branch pointing to the current commit, preserving your changes and allowing you to switch back to the branch later.