Practice Git & GitHub

You have a new project folder called my-project with a single file README.md. Initialise a Git repository, stage the file, and create an initial commit with the message "Initial commit".

# starting inside the my-project directory

git init
git add README.md
git commit -m "Initial commit"

Clone the repository at https://github.com/example/demo.git, create a branch called feature/navbar, make a new file navbar.html, commit it with the message "Add navbar", and push the branch to the remote.

git clone https://github.com/example/demo.git
cd demo
git switch -c feature/navbar
touch navbar.html
git add navbar.html
git commit -m "Add navbar"
git push -u origin feature/navbar

You are on main. Another developer's work lives on feature/header. When you run git merge feature/header, Git reports a conflict in index.html. Describe the steps to open the file, resolve the conflict markers, stage the resolved file, and complete the merge.

git merge feature/header
# --- conflict reported in index.html ---
# Open index.html, find and resolve all conflict markers:
#   <<<<<<< HEAD
#   ... your version ...
#   =======
#   ... incoming version ...
#   >>>>>>> feature/header
# Edit the file to keep the desired content, then:
git add index.html
git commit -m "Merge feature/header into main"

You are halfway through editing app.js on main when you need to switch to hotfix/typo to fix an urgent bug. Stash your current changes, switch to the hotfix branch, commit the fix, switch back to main, and then re-apply your stashed work.

git stash
git switch hotfix/typo
# fix the typo in the relevant file, then:
git add .
git commit -m "Fix typo in homepage copy"
git switch main
git stash pop

Your feature/payments branch was created from an older commit on main. New commits have since landed on main. Rebase feature/payments onto the latest main so the history stays linear, then switch to main, merge feature/payments with a fast-forward, and finally create an annotated tag v1.0.0 with the message "First stable release" and push both the branch and the tag.

git switch feature/payments
git rebase main
# resolve any rebase conflicts per file, then `git rebase --continue`
git switch main
git merge --ff-only feature/payments
git tag -a v1.0.0 -m "First stable release"
git push origin main
git push origin v1.0.0

You accidentally deleted a local branch feature/search with git branch -D feature/search. The branch has not been pushed to the remote. Use the reflog to find the tip commit of the deleted branch and recreate the branch pointing to that commit.

git reflog
# Scan the output for the last entry that mentions feature/search, e.g.:
# abc1234 HEAD@{3}: commit: add search bar component
git switch -c feature/search abc1234

A critical bugfix was committed to main as commit c0ffee1. You have a long-running support branch release/1.x that also needs this fix. Cherry-pick the commit onto release/1.x, then push the branch.

git switch release/1.x
git cherry-pick c0ffee1
# If there are conflicts, resolve them, then:
git add .
git cherry-pick --continue
git push origin release/1.x

Write a pre-commit hook that scans staged .ts and .tsx files for console.log statements and aborts the commit if any are found. Make the script executable and verify it runs on git commit.

#!/usr/bin/env bash
# .git/hooks/pre-commit
set -e

#!/usr/bin/env bash
# .git/hooks/pre-commit
set -e

STAGED=$(git diff --cached --name-only | grep -E '\.(ts|tsx)$' || true)

if [ -z "$STAGED" ]; then
  exit 0
fi

if echo "$STAGED" | xargs grep -l 'console\.log' 2>/dev/null; then
  echo "Error: console.log found in staged files. Remove it before committing."
  exit 1
fi

exit 0

# Make executable:
# chmod +x .git/hooks/pre-commit