Git & DevOps Version Control Interview Questions

'git init' creates a blank, local Git repository in an existing project directory, while 'git clone' copies an existing remote Git repository onto your local machine, automatically setting up a remote tracking link.

# Start a new local repository
mkdir my-new-project
cd my-new-project
git init

# Clone an existing remote repository
git clone https://github.com/careerraah/playwright-tests.git

'git status' displays the state of your working directory and staging area, listing files that are modified but unstaged, files staged for the next commit, and untracked files.

# Check current staging and working directory status
git status

'git add <file>' stages a single specific file, 'git add .' stages all new and modified files in the current folder and subfolders (but ignores deleted files in older Git versions), while 'git add -A' stages all changes globally, including modifications, additions, and deletions.

# Stage a single file
git add src/tests/login.spec.ts

# Stage all files in the current directory tree
git add .

# Stage all changes in the entire repository (including deletions)
git add -A

'git commit' saves your staged changes to the local repository's version history, creating a unique commit hash. The '-m' flag allows you to write the commit message directly in the terminal instead of opening a default text editor.

# Commit staged changes with a inline message
git commit -m "feat(auth): add email verification to login tests"

'git push' uploads your local branch commits to the remote repository (e.g. GitHub), while 'git pull' downloads (fetches) the latest changes from the remote repository and automatically merges them into your active local branch.

# Push local commits to remote branch
git push origin feature-login

# Pull latest changes from remote tracking branch
git pull origin main

'git log' displays the chronological history of commits on your active branch, while 'git diff' displays the line-by-line differences between your current working directory and the staged index (unstaged changes).

# View commit history
git log

# View simplified one-liner history
git log --oneline

# View unstaged code changes
git diff

# View staged changes preparing for commit
git diff --staged

Use 'git branch' to list local branches, 'git branch <branch_name>' to create a new branch, and 'git checkout <branch_name>' (or 'git switch <branch_name>') to switch branches. You can also run 'git checkout -b <branch_name>' to create and switch in one step.

# List all local branches
git branch

# Create a new feature branch
git branch feature-dashboard

# Switch to the feature branch
git checkout feature-dashboard
# OR: git switch feature-dashboard

# Create and switch in a single command
git checkout -b feature-payment
# OR: git switch -c feature-payment

A Fast-Forward merge occurs when the source branch has no new commits since the target branch branched off, allowing Git to simply move the target pointer forward. A 3-Way merge occurs when both branches have diverged with new commits, requiring Git to create a new 'Merge Commit' combining the histories.

# Merge branch into current (triggers Fast-Forward if main is unmodified)
git checkout main
git merge feature-login

# Force a merge commit (no fast-forward) for tracking pull requests
git merge --no-ff feature-login

A merge conflict occurs when two branches make conflicting edits to the exact same line of a file (or one deletes a file the other modified) and Git cannot determine which version to keep. It must be resolved manually by editing the conflicted files, staging them, and committing.

# Run merge and check status if it fails
git merge feature-payment

# (Edit files to resolve conflict markers)

# Stage resolved files
git add src/payments.ts

# Complete merge execution
git commit -m "merge: resolve merge conflicts in payments"

Identity is configured using 'git config user.name' and 'git config user.email'. Global configurations apply to all repositories on your local computer, while local configurations override global values for a single specific repository.

# Set global user name and email
git config --global user.name "John Doe"
git config --global user.email "john.doe@personal.com"

# Override for a specific work project repository
cd work-repos/fintech-app
git config user.email "jdoe@company.com"