🚀Git Interview Qusetions

✅ Git & GitHub Interview Questions (1–20)

Level: Senior DevOps | Focus: Real-world Scenarios, Tricky Use Cases

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1. What’s the difference between git fetch and git pull?

Answer:

• git fetch retrieves updates from a remote without applying them.

• git pull does git fetch + git merge (or git rebase depending on config).

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2. How do you resolve a merge conflict in Git?

Answer:

• Open conflicted files.

• Manually edit sections marked with <<<<<<<, =======, >>>>>>>.

• Stage resolved files and commit.

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3. You accidentally committed sensitive data. How do you remove it from the repo's history?

Answer:

• Use git filter-branch (older) or git filter-repo (new tool).

• Remove sensitive file and force-push.

• Rotate secrets immediately.

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4. What’s the difference between git reset and git revert?

Answer:

• git reset alters commit history (destructive).

• git revert adds a new commit that reverses changes (non-destructive).

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5. Scenario: How do you cherry-pick a commit from another branch without switching branches?

Answer:

git cherry-pick <commit-hash>

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6. What’s the use of .gitignore vs .gitkeep?

Answer:

• .gitignore tells Git which files/folders to ignore.

• .gitkeep is not a Git feature; it's a placeholder to keep empty folders tracked.

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7. You deleted a branch locally but it still exists remotely. How do you delete it from GitHub?

Answer:

git push origin --delete <branch-name>

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8. How do you recover a commit that was just reset with git reset --hard?

Answer:
Use git reflog to find the commit and reset to it:

git reflog
git reset --hard <commit>

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9. Scenario: A junior dev accidentally did a git push --force and erased history. How do you recover?

Answer:

• Use reflog from another clone.

• Create a patch or fetch backup from CI/CD artifact, if available.

• Encourage enabling branch protection.

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10. What is the use of Git tags in CI/CD pipelines?

Answer:

• Tags represent stable release points (v1.0.0, etc.).

• Pipelines often trigger on push tags to deploy releases.

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11. How do you squash multiple commits into one after a feature is complete?

Answer:

git rebase -i HEAD~n

• Replace pick with squash or s on later commits.

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12. How can you prevent accidental force-pushes to the main branch?

Answer:

• GitHub branch protection rules.

• receive.denyNonFastForwards = true on Git server.

• Set push.default = simple.

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13. Scenario: Git history is bloated with unnecessary binary files. What do you do?

Answer:

• Use git filter-repo to clean history.

• Add *.bin or similar to .gitignore.

• Use Git LFS if binaries are needed.

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14. How do you create a Git alias for frequent commands like git log --oneline --graph?

Answer:

git config --global alias.lg "log --oneline --graph --all"

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15. Explain Git LFS and when to use it.

Answer:
Git LFS (Large File Storage) stores large files (media, binaries) outside normal Git storage to reduce repo size and improve performance.

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16. Scenario: You get non-fast-forward error when pushing. What do you do?

Answer:

• First try: git pull --rebase

• If intended to overwrite: git push --force-with-lease (safer than --force)

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17. What is a detached HEAD state, and how do you get out of it?

Answer:

• Happens when you checkout a commit instead of a branch.

• Fix by:

    git checkout <branch-name>
  

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18. How do you revert a specific file from an older commit?

Answer:

git checkout <commit-hash> -- path/to/file

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19. How do you track changes to submodules in Git?

Answer:

• Submodules are fixed to a specific commit.

• To update:

    git submodule update --remote
  

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20. Scenario: Multiple developers push conflicting changes to the same branch. How do you manage this?

Answer:

• Enable protected branches with review rules.

• Encourage feature branches + PR process.

• Rebase locally before push to reduce conflicts.

✅ Git & GitHub Interview Questions (21–40)

Level: Senior DevOps | Focus: Advanced Workflows, Troubleshooting, CI/CD Use Cases

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21. Scenario: You need to test a feature locally from a remote GitHub PR without merging it. How would you do that?

Answer:

git fetch origin pull/<PR_ID>/head:pr-branch
git checkout pr-branch

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22. How do you enforce commit message standards in a GitHub repo?

Answer:

• Use commit hooks via Husky or pre-commit.

• Enforce checks using CI/CD (e.g., GitHub Actions, GitLab CI).

• Optionally integrate tools like commitlint.

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23. What is the purpose of a .gitmodules file?

Answer:
It records submodule information — remote URL and path inside the main repo.

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24. Scenario: CI pipeline triggers multiple times for a single PR. What might be wrong in GitHub Actions workflow?

Answer:
Likely caused by using both pull_request and push triggers. Solution:

  on:
    pull_request:
      branches: [main]

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25. How can you automate version tagging in Git during CI/CD releases?

Answer:

• Use git tag v<version> and git push origin --tags.

• Automate with tools like semantic-release or write custom scripts in CI.

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26. Scenario: GitHub Actions is failing to checkout a private submodule. How do you fix it?

Answer:

• Provide SSH or token access in the workflow:

    - uses: actions/checkout@v3
      with:
        submodules: recursive
        token: ${{ secrets.GITHUB_TOKEN }}
  

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27. What’s the difference between origin/master and master?

Answer:

• master: Your local branch.

• origin/master: The state of master on the remote the last time you fetched.

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28. How do you ensure your GitHub repository is secure for production code?

Answer:

• Enable branch protection and required reviews.

• Use Dependabot for dependency scanning.

• Enforce signed commits.

• Use CodeQL analysis.

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29. What is the difference between git stash and git stash pop?

Answer:

• git stash saves changes temporarily.

• git stash pop restores changes and deletes stash entry.

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30. Scenario: Your Git repo is 1 GB due to logs and build artifacts. What’s your cleanup strategy?

Answer:

• Add them to .gitignore.

• Clean history with git filter-repo or BFG.

• Use Git LFS if needed for large files.

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31. What is git rebase --onto used for?

Answer:
Rebase a branch onto a different base:

git rebase --onto new-base old-base feature

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32. Scenario: GitHub Actions workflow needs to skip a step if commit message contains [skip ci]. How do you do that?

Answer:
Use an if condition:

if: "!contains(github.event.head_commit.message, '[skip ci]')"

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33. How do you create a signed Git commit?

Answer:

    git commit -S -m "Your commit message"

• Requires GPG key setup.

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34. Scenario: Someone force-pushed to the main branch and removed 10 commits. How do you restore?

Answer:

• If reflog is available:

    git reflog
    git reset --hard <old_commit>
  

  If not, retrieve from backup clone or CI artifacts.

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35. What’s the difference between git archive and git bundle?

Answer:

• git archive: Creates a tar/zip of the current tree — no Git history.

• git bundle: Backs up complete Git history, used for offline clones.

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36. How do you generate a patch from Git commits and apply it in another repo?

Answer:

git format-patch -1 <commit>
git apply patchfile.patch

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37. Scenario: A developer is working directly on the main branch. How would you enforce feature branches only?

Answer:

• Protect main branch.

• Require PRs and reviews.

• Add push restrictions.

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38. What are orphan branches in Git?

Answer:

Created with no parent history:

git checkout --orphan gh-pages

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39. How do you force Git to overwrite local changes during pull?

Answer:

git fetch origin
git reset --hard origin/main

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40. Scenario: You accidentally committed to the wrong branch. What do you do?

Answer:

git checkout correct-branch
git cherry-pick <commit>
git checkout wrong-branch
git reset --hard HEAD~1

✅ Git & GitHub Interview Questions (41–60)

Level: Senior DevOps | Focus: CI/CD, Collaboration, Troubleshooting, Advanced GitOps

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41. Scenario: How would you create a GitHub Action that only runs on changes in a backend/ folder?

Answer:

    on:
      push:
        paths:
          - 'backend/**'

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42. What is the difference between HEAD, HEAD^, and HEAD~1 in Git?

Answer:

• HEAD: current commit.

• HEAD^: parent of HEAD.

• HEAD~1: first ancestor of HEAD (same as HEAD^ but can go deeper, e.g., HEAD~2).

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43. How do you configure Git to use a specific user/email for a specific repo only?

Answer:

git config user.name "DevOps Sr"
git config user.email "devops@example.com"

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44. Scenario: You want to prevent direct commits to the main branch but allow merges via PR only. How?

Answer:

• Enable Branch Protection Rules on GitHub:

• Require pull requests.

• Disallow force pushes.

• Require status checks or approvals.

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45. What does git describe do and how is it useful?

Answer:

• Shows human-readable name for the current commit using tags.

• Useful for release versions:

    git describe --tags
  

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46. How do you clean up all local branches that have been deleted on the remote?

Answer:

git fetch -p
git branch -vv | grep ': gone]' | awk '{print $1}' | xargs git branch -d

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47. Scenario: You want to mirror an internal Git repo to GitHub. How do you do that?

Answer:

git clone --mirror git@internal/repo.git
cd repo.git
git push --mirror git@github.com:user/repo.git

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48. What is the difference between shallow and deep clones in Git?

Answer:

• Shallow clone (--depth=1): only latest commit.

• Full clone: entire history.

• Use shallow clone for CI/CD to speed up builds.

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49. Scenario: Your team commits large files by mistake. How to prevent this proactively?

Answer:

• Use .gitattributes + Git LFS.

• Pre-commit hook with size checks:

    find . -size +5M
  

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50. What are the different merge strategies available in Git?

Answer:

• recursive (default).

• ours.

• theirs.

• octopus (for merging >2 branches).

• resolve.

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51. Scenario: You are working on multiple features in parallel. How do you manage this efficiently in Git?

Answer:

• Use feature branches.

• Rebase regularly from main to avoid drift.

• Stash uncommitted changes between contexts.

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52. What is a Git worktree and when should you use it?

Answer:

• It allows multiple working directories linked to the same repo.

• Useful for working on multiple branches simultaneously.

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53. Scenario: A developer complains their GitHub Action secrets are not being read. What could be wrong?

Answer:

• Secrets are not available to forks by default.

• Secrets must be defined at repo or org level.

• Check for typos: secrets.SECRET_NAME.

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54. How does git bisect work?

Answer:

• Helps identify the commit that introduced a bug using binary search.

• Command flow:

    git bisect start
    git bisect bad
    git bisect good <commit>
  

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55. Scenario: You need to trigger a GitHub Action from another repo. How do you approach it?

Answer:

• Use repository_dispatch:

• Trigger with a token from one repo.

• Accept in the target repo’s workflow:

    on: repository_dispatch
  

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56. What is the difference between git blame and git log -L?

Answer:

• git blame: shows the author of each line.

• git log -L: tracks history of a specific line/range of lines.

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57. How do you manage Git credentials securely on CI/CD runners?

Answer:

• Use environment variables or GitHub/GitLab secrets.

• Avoid storing .netrc or plaintext tokens in the repo.

• Use deploy keys or fine-scoped PATs.

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58. Scenario: A developer pushes directly to main via CLI even though PRs are required. Why?

Answer:

• Likely branch protection rule is not enforced for admins.

• Check and enable “Include administrators” option.

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59. How do you detect and fix a “dangling commit”?

Answer:

• Use:

    git fsck --lost-found
    git reflog
  

  Recover with:

    git checkout <dangling-commit>
  

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60. Scenario: You want to enable signed commits for all contributors. How?

Answer:

• Enforce via GitHub branch protection rules: Require signed commits.

• Each user must configure GPG key locally.

✅ Git & GitHub Interview Questions (61–80)

Level: Senior DevOps | Focus: GitOps, CI/CD, Enterprise GitHub Usage, Recovery & Automation

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61. Scenario: You’re implementing GitOps for Kubernetes deployments. What role does Git play in GitOps?

Answer:

• Git acts as the single source of truth for the desired cluster state.

• Git commits trigger reconciliation by tools like ArgoCD or Flux.

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62. How do you handle secrets in a GitOps setup with GitHub repositories?

Answer:

• Never commit secrets to Git.

• Use sealed secrets, external secret stores (like HashiCorp Vault or SOPS).

• Manage access through GitHub Actions secrets or encrypted files.

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63. What is the purpose of the --force-with-lease option in git push?

Answer:

• It ensures you're only force-pushing if no one else has updated the branch since your last fetch, adding safety over --force.

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64. Scenario: A developer merged a large binary file, which bloated the repository. How do you remove it efficiently?

Answer:

• Use:

    git filter-repo --path filename --invert-paths
  

  Then run:

    git gc --prune=now --aggressive
  

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65. What is git bundle and when would you use it?

Answer:

• It creates a portable Git repository as a single file.

• Useful for offline backup, air-gapped environments, or transferring without network.

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66. Scenario: CI jobs are failing due to incorrect .gitmodules entries. What’s the fix?

Answer:

• Update .gitmodules with correct URLs.

  Run:

    git submodule sync
    git submodule update --init --recursive
  

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67. How do you compare two branches and list only the files that differ?

Answer:

git diff --name-only branch1..branch2

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68. How can you squash the last N commits into one without changing the commit message?

Answer:

git reset --soft HEAD~N
git commit --amend

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69. Scenario: You want to enforce specific labels before merging a PR. How do you do that?

Answer:

• Use GitHub Actions or Probot apps.

• Define a job that fails if required labels are missing:

    if: contains(github.event.pull_request.labels.*.name, 'approved')
  

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70. What’s the best way to mirror a GitHub repository to a self-hosted Git server continuously?

Answer:

• Use GitHub webhooks to trigger mirroring scripts.

• Optionally, use CI tools (GitHub Actions) to automate push to the mirror on every push event.

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71. Scenario: A collaborator complains that their PR was merged without review. How do you prevent this?

Answer:

• Enable “Require pull request reviews before merging” under GitHub Branch Protection Rules.

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72. What does the --no-ff flag do in a git merge?

Answer:

• Forces creation of a merge commit even when a fast-forward is possible, preserving branch history.

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73. Scenario: You're investigating why GitHub Action secrets aren't accessible in forked PRs. Why?

Answer:

• Secrets are not exposed to workflows triggered from forks due to security reasons.

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74. How do you reapply a commit that was reverted earlier?

Answer:

git cherry-pick <reverted-commit-hash>

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75. What’s the purpose of git rerere?

Answer:

• Stands for “reuse recorded resolution”.

• Automatically re-applies previous merge conflict resolutions.

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76. Scenario: Git clone takes too long due to large history. What are your options?

Answer:

• Use:

    git clone --depth 1
  

  Clean up history with filter-repo or use Git LFS.

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77. What is a rebase interactive (git rebase -i) used for?

Answer:

• Used to edit, squash, reorder, or remove commits.

• Ideal for cleaning up feature branches before merging.

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78. Scenario: A teammate wants to contribute but doesn’t want to fork the repo. How do you securely give them access?

Answer:

• Add them as a collaborator with limited permission (Write or Triage).

• Use protected branches and required reviews for safety.

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79. What is the difference between git diff and git status?

Answer:

• git diff: shows line-by-line changes.

• git status: shows staged, unstaged, and untracked file statuses.

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80. Scenario: CI pipeline is always rebuilding everything, even on small changes. How do you optimize this?

Answer:

• Use caching (e.g., GitHub Actions cache).

• Use checksum comparison on files.

• Split monolith workflows using path-based triggers.

✅ Git & GitHub Interview Questions (81–100)

Level: Senior DevOps | Focus: Failures, Internals, GitHub Enterprise, GitOps Security, Team Collaboration

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81. Scenario: A teammate accidentally removed a Git tag used for production deployment. How do you recover it?

Answer:

• Check with:

    git reflog show --tags
  

  Recreate:

    git tag <tag> <commit>
    git push origin <tag>
  

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82. What is the .gitattributes file used for?

Answer:

• Controls how Git treats files (e.g., line endings, merge strategy).

• Used for Git LFS, custom diff, and filters.

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83. How do you automatically delete a feature branch after PR is merged in GitHub?

Answer:

• Enable "Automatically delete head branches" in repo settings under General → Pull Requests.

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84. Scenario: Two devs push the same file with different changes at the same time. GitHub merges both. Why no conflict?

Answer:

• If changes are in different lines, Git can automatically merge.

• Conflicts only arise with overlapping line changes.

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85. What does git rev-parse HEAD return?

Answer:

• The full SHA-1 hash of the latest commit (HEAD).

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86. What is the difference between git clone --mirror and git clone --bare?

Answer:

• --bare: no working directory, used on servers.

• --mirror: includes remote-tracking branches and config, good for repo backup.

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87. Scenario: CI/CD fails due to GitHub rate-limiting. How can this be mitigated?

Answer:

• Use a GitHub token with higher quota, or cache dependencies.

• Switch to SSH instead of HTTPS.

• Use GitHub Enterprise for higher limits.

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88. What is a fast-forward merge and when is it preferred?

Answer:

• A merge where the target branch is directly updated without a new merge commit.

• Preferred for linear history when no divergent commits exist.

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89. Scenario: You're setting up a monorepo with multiple CI workflows. How do you optimize?

Answer:

• Use path-based triggers in GitHub Actions:

    on:
      push:
        paths:
          - 'service-a/**'
  

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90. How do you list all commits that modified a specific file?

Answer:

git log --follow -- path/to/file

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91. What is a shallow submodule clone?

Answer:

• Cloning submodules with --depth=1 to reduce fetch time:

    git submodule update --init --depth 1
  

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92. Scenario: A GitHub Actions workflow is stuck. How do you debug it?

Answer:

• Check Actions logs.

• Enable ACTIONS_STEP_DEBUG and ACTIONS_RUNNER_DEBUG secrets.

• Add echo/printenv commands for inspection.

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93. What is the difference between fork and clone in GitHub context?

Answer:

• Clone: copies a repo locally.

• Fork: copies a repo to your GitHub account with history, enabling pull requests back to original.

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94. What are monorepos and what Git challenges do they pose?

Answer:

• Monorepos contain multiple projects in one Git repo.

• Challenges: long CI times, complex history, merge conflicts, partial builds.

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95. Scenario: GitHub Actions workflow should only run on PR to main, but it's running on all branches. Why?

Answer:

• Misconfigured trigger:

    on:
      pull_request:
        branches: [main]
  

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96. What is Git’s object model composed of?

Answer:

• Four main objects: blob, tree, commit, and tag.

• Stored in .git/objects.

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97. How does Git handle line endings across OS (Windows vs Linux)?

Answer:

• With .gitattributes and core.autocrlf:

• true: converts LF → CRLF on checkout.

• input: converts CRLF → LF on commit.

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98. Scenario: You accidentally committed large secrets. You removed them and force pushed. Is that enough?

Answer:

• Not enough. Git history still contains them.

• Use git filter-repo or BFG Repo Cleaner.

• Revoke secrets immediately.

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99. How do you enable automatic branch creation in GitHub when pushing to a new remote branch?

Answer:

git push -u origin new-branch

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100. Scenario: You need to prove audit integrity of your repo. How does Git support this?

Answer:

• Git’s history is cryptographically secure (SHA-1).

• Use signed commits and tags.

• GitHub supports GPG and SSH verification badges.

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