The Ultimate Git Q&A Guide (Beginner to Expert)

Git is the backbone of modern software development. Whether you are a beginner just learning git init or an advanced user managing complex workflows with git rebase, this Q&A post has you covered.

1. What is core.excludesFile in Git?

Answer:
The core.excludesFile setting in Git defines the global ignore file (similar to .gitignore, but system-wide).

  • By default, .gitignore works per project.
  • core.excludesFile is useful when you want to ignore files across all repositories on your machine (e.g., .DS_Store, IDE configs, log files).

👉 Example:

git config --global core.excludesFile ~/.gitignore_global

Then create a file ~/.gitignore_global and add patterns like:

*.log
.DS_Store
node_modules/

2. What does git branch -f branch-name do?

Answer:
git branch -f force-moves a branch pointer to a specific commit. It’s useful when you want to reset a branch without checking it out.

👉 Example: Move dev branch to match main:

git branch -f dev main

Now dev points exactly where main is.

⚠️ Be careful — this changes commit history for that branch pointer.

3. How does git stash work?

Answer:
git stash temporarily saves your uncommitted changes (both staged and unstaged) so you can work on something else without committing.

👉 Example:

git stash         # saves changes
git stash list    # see all stashes
git stash pop     # reapply latest stash and remove it
git stash apply   # reapply without removing

4. Difference between git stash pop and git stash apply?

  • git stash pop → applies the stash and removes it from the stash list.
  • git stash apply → applies the stash but keeps it in the list.

5. How to use git apply?

Answer:
git apply applies a patch (like a diff) directly to your working directory without committing.

👉 Example:

git diff > fix.patch
git apply fix.patch

This is useful when you want to share changes as patches instead of pushing branches.

6. How to explore history with git log?

Answer:
git log shows commit history. Some useful options:

git log --oneline --graph --decorate --all
  • --oneline → short hash & message
  • --graph → ASCII branch graph
  • --decorate → shows branch/tags
  • --all → shows all refs

7. How to compare changes with git diff?

Answer:

  • Compare working directory vs. index (unstaged changes): git diff
  • Compare staged changes vs. last commit: git diff --cached
  • Compare two commits: git diff commit1 commit2

8. What is git merge vs. git rebase?

Answer:

  • git merge branchX → merges branch history, creates a merge commit (keeps history intact).
  • git rebase branchX → re-applies commits on top of branchX, creating a linear history.

👉 Use merge for shared branches.
👉 Use rebase for private branches before pushing.

9. How does git fetch differ from git pull?

  • git fetch → downloads changes from remote but does not merge into your branch.
  • git pull = git fetch + git merge (or git rebase if you use --rebase).

10. How to move/rename a file with git mv?

git mv old.txt new.txt
git commit -m "Renamed file"

This keeps history intact instead of manually deleting & re-adding files.

11. What is git pull --rebase?

Answer:
It fetches changes and rebases your commits on top of the updated branch (instead of creating a merge commit).

👉 Example:

git pull --rebase origin main

This keeps history linear.

12. How to use git clean?

Answer:
Removes untracked files (careful ⚠️).

git clean -fd
  • -f → force
  • -d → remove untracked dirs

13. How to clone a repo into a subdirectory?

git clone https://github.com/user/repo.git my-subdir

This creates the repo inside my-subdir.

14. How to find who changed a line with git blame?

git blame file.txt

Shows commit hash, author, and time for each line.

👉 Useful with -L to blame specific lines:

git blame -L 10,20 file.txt

15. How to ignore all files except one?

In .gitignore:

*
!file.txt

This ignores everything except file.txt.

16. How to undo a merge commit?

If not pushed yet:

git reset --hard HEAD~1

If pushed, use git revert:

git revert -m 1 <merge_commit_hash>

This undoes merge without rewriting history.

17. What is git switch?

  • git switch branch → switches branches.
  • git switch -c new-branch → creates & switches to new branch.

👉 It’s a modern alternative to git checkout (for branches).

18. What are Git Hooks?

Answer:
Git hooks are scripts that run automatically on certain events (like commits, pushes).

Examples in .git/hooks/:

  • pre-commit → run tests before committing
  • pre-push → check code quality before pushing
  • commit-msg → enforce commit message rules

👉 Hooks make Git workflows automated & consistent.

🚀 Final Thoughts

This Q&A covered everything from basic commands like git stash to advanced tricks like core.excludesFile, undoing merges, and Git hooks. Bookmark this page, and you’ll never get stuck in Git again.

👉 Share this with your dev friends. Every developer has been stuck with Git at least once 😉

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