Repository (committed history) in Git - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of git log --oneline -3?

You run the command git log --oneline -3 in a repository with 5 commits. What will this command show?

Git

git log --oneline -3

A Shows the first 3 commits made in the repository with short hashes.

B Shows all 5 commits with full commit hashes and detailed commit messages.

C Shows the last 3 commits with their short commit hashes and commit messages.

D Shows only the commit messages of the last 3 commits without hashes.

💡 Hint

Think about what --oneline and -3 do in git log.

The --oneline option shows each commit in one line with a short hash and message. The -3 limits the output to the last 3 commits.

🧠 Conceptual

intermediate

What does the HEAD pointer represent in a Git repository?

In Git, what is the role of the HEAD pointer?

A <code>HEAD</code> points to the latest commit on the current branch you are working on.

B <code>HEAD</code> is the name of the remote repository.

C <code>HEAD</code> stores the list of all branches in the repository.

D <code>HEAD</code> is a backup of the repository before the last commit.

💡 Hint

Think about what Git uses to know your current working snapshot.

HEAD is a pointer that tells Git which commit your working directory is based on, usually the latest commit on your current branch.

❓ Troubleshoot

advanced

Why does git log --graph show a disconnected commit?

You run git log --graph and see a commit that is not connected to the main branch history. What could cause this?

Git

git log --graph

A The commit was deleted but still appears due to caching.

B The commit is corrupted and Git cannot link it properly.

C The repository is empty and has no commits.

D The commit belongs to a branch that was never merged into the main branch.

💡 Hint

Think about how branches and merges affect commit history graphs.

A commit that is not connected usually means it is on a branch that was never merged, so it does not appear in the main branch's history graph.

🔀 Workflow

advanced

What is the effect of git reset --hard HEAD~2?

What happens when you run git reset --hard HEAD~2 in your repository?

Git

git reset --hard HEAD~2

A Moves the current branch pointer back by 2 commits and resets the working directory and staging area to match that commit.

B Deletes the last 2 commits permanently from the remote repository.

C Creates a new branch named <code>HEAD~2</code>.

D Stashes the last 2 commits for later use.

💡 Hint

Consider what reset --hard does to the branch pointer and files.

git reset --hard HEAD~2 moves the current branch pointer back two commits and updates the working directory and index to match that commit, discarding changes after it.

✅ Best Practice

expert

Which Git command safely shows the commit history including merges with a clear visual graph?

You want to see the full commit history including merges, with a clear visual graph and branch names. Which command is best?

A git diff --graph

B git log --graph --oneline --all --decorate

C git show --graph

D git log --stat

💡 Hint

Look for options that show graph, all branches, and decorate with branch names.

git log --graph --oneline --all --decorate shows a visual graph of all commits including merges, with short commit info and branch names.