HEAD pointer concept in Git - Step-by-Step Execution

Process Flow - HEAD pointer concept

Start: Repository with commits

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HEAD points to current branch

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Branch points to latest commit

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Checkout changes HEAD

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HEAD moves to new branch or commit

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Working directory reflects HEAD state

HEAD is a pointer that shows which commit or branch you are currently working on. When you switch branches or commits, HEAD moves to point there.

Execution Sample

Git

git checkout main
# HEAD points to 'main' branch

git checkout feature
# HEAD moves to 'feature' branch

git checkout abc1234
# HEAD points to commit abc1234 (detached)

This sequence shows HEAD moving from one branch to another and then to a specific commit (detached HEAD).

Process Table

Step	Command	HEAD points to	Branch/Commit	Working Directory State
1	Initial state	main	branch 'main' at commit C3	Files at commit C3
2	git checkout feature	feature	branch 'feature' at commit C5	Files at commit C5
3	git checkout abc1234	abc1234	commit abc1234 (detached)	Files at commit abc1234
4	git checkout main	main	branch 'main' at commit C3	Files at commit C3

💡 After step 4, HEAD points back to 'main' branch; working directory matches that commit.

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 4
HEAD	main	feature	abc1234 (detached)	main
Working Directory	C3 files	C5 files	abc1234 files	C3 files

Key Moments - 3 Insights

Why does HEAD sometimes point directly to a commit instead of a branch?

When you checkout a specific commit (like in step 3), HEAD points directly to that commit, called a 'detached HEAD'. This means you are not on any branch.

What happens to the working directory when HEAD moves?

The working directory updates to match the commit HEAD points to, as shown in the 'Working Directory State' column in the execution table.

Does HEAD always point to a branch?

No, HEAD usually points to a branch, but can point directly to a commit in detached mode (step 3).

Visual Quiz - 3 Questions

Look at the execution table, what does HEAD point to after step 3?

A branch 'feature'

B commit abc1234 (detached)

C branch 'main'

D no pointer

💡 Hint

Check the 'HEAD points to' column in row for step 3.

At which step does the working directory change to files from commit C5?

A Step 2

B Step 1

C Step 3

D Step 4

💡 Hint

Look at the 'Working Directory State' column for each step.

If you checkout a new branch from commit abc1234, what happens to HEAD?

A HEAD points to 'main'

B HEAD stays detached at abc1234

C HEAD points to the new branch

D HEAD is removed

💡 Hint

HEAD always points to the current branch unless detached; creating a new branch moves HEAD there.

Concept Snapshot

HEAD is a pointer to your current branch or commit.
When you switch branches, HEAD moves to that branch.
Checking out a commit directly detaches HEAD.
Working directory updates to match HEAD's commit.
Detached HEAD means no branch is checked out.

Full Transcript

The HEAD pointer in git shows where you currently are in your project history. It usually points to a branch, which itself points to a commit. When you use 'git checkout' to switch branches, HEAD moves to that branch. If you checkout a specific commit, HEAD points directly to that commit, called a detached HEAD. The files in your working directory always match the commit HEAD points to. This helps git know what you are working on and where new commits will be added.