Question 1

What is Git and why is it used?

Accepted Answer

Git is a distributed version control system that tracks changes in source code during software development. It allows multiple developers to work on the same project simultaneously, maintains complete history of changes, enables branching and merging, and provides backup through remote repositories. Git is fast, secure, and works offline.

Question 2

What is the difference between git add and git commit?

Accepted Answer

git add stages changes by moving them from the working directory to the staging area (index), preparing them for commit. git commit takes all staged changes and permanently records them in the repository history with a message. Think of add as selecting what to include, and commit as saving the snapshot.

Question 3

What is a branch in Git and why is branching useful?

Accepted Answer

A branch is an independent line of development that diverges from the main codebase. Branching allows developers to work on features, fixes, or experiments in isolation without affecting the main code. It enables parallel development, safe experimentation, and organized workflows like feature branches and release branches.

Question 4

What is the difference between git pull and git fetch?

Accepted Answer

git fetch downloads commits and refs from a remote repository but doesn't integrate them into your working branch—it only updates remote-tracking branches. git pull is essentially git fetch followed by git merge, automatically merging remote changes into your current branch. Fetch is safer for reviewing changes before integrating.

Question 5

How do you handle merge conflicts?

Accepted Answer

When Git can't automatically merge changes, it marks conflicts in the affected files with <<<<<<, ======, and >>>>>> markers. To resolve: 1) Open conflicted files, 2) Manually edit to keep desired changes and remove markers, 3) Stage resolved files with git add, 4) Complete the merge with git commit. Tools like VS Code provide visual conflict resolution.

Question 6

What is the difference between a merge and a rebase?

Accepted Answer

Merge creates a new commit that combines two branches, preserving complete history with a merge commit. Rebase replays your commits on top of another branch, creating a linear history without merge commits. Merge is safer for shared branches; rebase creates cleaner history but should never be used on public/shared branches.

Question 7

What is HEAD in Git?

Accepted Answer

HEAD is a pointer that references the current commit you're working on, typically the latest commit of your current branch. It represents your current position in the repository's history. When you checkout a branch, HEAD points to that branch. Detached HEAD occurs when HEAD points directly to a commit instead of a branch.

Question 8

How do you undo or revert a commit?

Accepted Answer

Several options exist: git revert <commit> creates a new commit that undoes changes (safe for shared history). git reset --soft HEAD~1 moves HEAD back, keeping changes staged. git reset --hard HEAD~1 completely removes the commit and changes (destructive). For unpushed commits, reset is fine; for pushed commits, use revert.

Question 9

What is .gitignore and how should it be used?

Accepted Answer

.gitignore is a file specifying patterns for files and directories that Git should ignore. Common entries include node_modules/, .env, *.log, build/, and IDE settings. Place it in the repository root. It only affects untracked files—already tracked files must be removed with git rm --cached before being ignored.

Question 10

What is git stash and when would you use it?

Accepted Answer

git stash temporarily saves uncommitted changes (both staged and unstaged) and reverts the working directory to a clean state. Use it when you need to switch branches but aren't ready to commit current work. Retrieve stashed changes with git stash pop (applies and removes) or git stash apply (applies and keeps stash).

Question 11

What are best practices for commit messages?

Accepted Answer

Good commit messages have a short subject line (50 chars max) in imperative mood ('Add feature' not 'Added feature'), followed by a blank line and detailed body if needed. Be specific about what changed and why. Reference issue numbers when applicable. Avoid vague messages like 'fix bug' or 'update code'.

Question 12

What is cherry-picking in Git?

Accepted Answer

Cherry-picking applies a specific commit from one branch to another without merging the entire branch. Use git cherry-pick <commit-hash> to copy a commit to your current branch. It's useful for selectively applying bug fixes or features. The cherry-picked commit gets a new hash since it's technically a new commit.

Question 13

How do you squash multiple commits into one?

Accepted Answer

Use interactive rebase: git rebase -i HEAD~n (where n is the number of commits). In the editor, change 'pick' to 'squash' or 's' for commits you want to combine into the previous one. Save and edit the combined commit message. Only squash commits that haven't been pushed to shared branches.

Question 14

What is the Gitflow workflow?

Accepted Answer

Gitflow is a branching model with defined branch types: main (production), develop (integration), feature/* (new features), release/* (release preparation), and hotfix/* (urgent fixes). Features branch from develop and merge back; releases branch from develop and merge to both main and develop. It's suited for scheduled release cycles.

Question 15

How do you manage sensitive information in Git?

Accepted Answer

Never commit sensitive data like passwords, API keys, or credentials. Use .gitignore for config files containing secrets. Use environment variables or secret management tools. If secrets were accidentally committed, use git filter-branch or BFG Repo-Cleaner to remove them from history, then rotate all exposed credentials immediately.

Fundamentals(6 questions)

What is Git, and why is it used?

What is HEAD in Git?

How does Git differ from other version control systems like SVN or Mercurial?

What is a repository in Git?

How do you initialize a new Git repository in a project?

Can you explain the concept of a "commit" in Git?

Basic Operations(5 questions)

What is the difference between git add and git commit?

How do you check the status of your working directory and staging area?

How do you discard local changes to a file in your working directory?

What are the different ways to revert or undo a commit?

How do you compare differences between two commits, branches, or files?

Branching and Merging(5 questions)

What is a branch in Git, and why is branching useful?

How do you create a new branch, and how do you switch to it?

What is a merge, and how does it work in Git?

Can you explain the difference between a merge and a rebase?

How do you handle merge conflicts?

Remote Repositories(5 questions)

How do you add a remote repository to your local Git repo?

What's the difference between git pull and git fetch?

How do you clone a remote repository onto your local machine?

What is the purpose of git push?

How do you handle authentication when working with a remote repository?

Commit History and Logs(5 questions)

How do you view the commit log in Git?

What is git blame, and what is it used for?

How do you create an annotated tag in Git?

When should you use an annotated tag rather than a lightweight tag?

What is the difference between git log and git reflog?

Collaboration and Workflows(5 questions)

What is the "Gitflow" workflow, and when should it be used?

Can you explain how pull requests (or merge requests) fit into a development workflow?

How does one go about code review with Git?

What are some strategies to avoid merge conflicts in a collaborative environment?

How can you revert changes in a collaborative setting without losing your teammates' work?

Advanced Git Concepts(5 questions)

What is the difference between git rebase --interactive and a normal rebase?

Can you explain how to squash multiple commits into one?

What is the purpose of cherry-picking a commit, and how do you do it?

How do submodules work in Git, and why might you use them?

Can you describe the difference between shallow cloning and a full clone?

Performance and Optimization(5 questions)

What is Git garbage collection, and when is it triggered?

How do you optimize a repository's size?

When should you use git gc or git prune?

What is the .git folder, and what does it contain?

How do you handle large files and binary data in Git?

Security and Best Practices(5 questions)

How do you manage sensitive information in Git (e.g., credentials or config files)?

What is gitignore, and how should it be used?

What are some best practices for commit messages?

What is a signed commit, and why might it be important?

How can you securely remove a file that was previously committed and contains sensitive data?