100 Git Interview Questions & Answers

Git is a distributed version control system that tracks changes to files over time, letting multiple people work on the same codebase concurrently, branch off to work in isolation, and merge changes back together — used because it's the industry-standard way to manage source code history, enable collaboration, and recover from mistakes (nothing is truly lost as long as it's committed somewhere).

Git works completely independently of GitHub — you can use Git with no GitHub account at all (a local repo, or hosted on GitLab, Bitbucket, or your own server). GitHub is one of several popular hosting services built on top of Git, adding collaboration features Git itself doesn't provide.

A repository (repo) is the full set of files, folders, and their complete commit history, tracked by Git in a hidden .git directory at the project's root — that .git folder IS the repository; deleting it removes all Git tracking while leaving the working files themselves intact.

git add file.txt
git commit -m "Add feature X"

A commit is a permanent, addressable snapshot of the entire tracked project at a point in time, along with metadata (author, timestamp, message, and a pointer to its parent commit(s)) — commits form a chain (or graph, once branching enters the picture) that constitutes the project's history.

The working directory is where you actually edit files; git add moves selected changes into the staging area (a preview of exactly what the next commit will contain); git commit takes everything staged and permanently records it into the repository's history. This three-stage model is what lets you commit only part of your current changes, not everything you've touched.

git branch feature-x
git checkout feature-x
# or in one step:
git checkout -b feature-x

A branch is an independent, movable pointer to a commit — creating one lets you develop a feature or fix in isolation without affecting the main line of history, and merge it back only once it's ready. This is what makes parallel, non-blocking collaborative development practical.

HEAD is a pointer to whatever commit you currently have checked out — normally it points to a branch (which itself points to a commit), so HEAD moves along automatically as you commit on that branch; checking out a specific commit directly (rather than a branch) puts you in a "detached HEAD" state.

git clone https://github.com/user/repo.git

git clone copies an entire remote repository — every commit, branch, and tag in its full history — down to a new local directory, and automatically sets up that remote as origin, ready to push/pull against.

Git stores content as a graph of four object types, all content-addressed by SHA-1 (or SHA-256 in newer repos) hash: blobs (raw file content), trees (directory listings, mapping names to blob/tree hashes), commits (a snapshot pointer plus metadata and a parent link), and tags (a named pointer to a specific commit). Crucially, Git doesn't store per-file diffs — every commit points to a full snapshot of the entire tree, with unchanged files simply reusing the same blob hash they already had.