Front-end Web Development Version Control Syllabus

What command creates a new branch?

git branch <name> creates the branch (without switching to it); git checkout -b <name> or git switch -c <name> creates it and switches to it.

What command switches your working directory to a different branch?

git checkout <branch> or the newer git switch <branch>. HEAD then points to that branch and the working tree updates to match.

What is HEAD in Git?

A reference to the current commit you have checked out — usually a symbolic pointer to the tip of the current branch. It determines the parent of your next commit.

What is a detached HEAD state?

When HEAD points directly to a specific commit rather than to a branch. New commits made there are not on any branch and can be lost unless you create a branch to capture them.

What command combines the history of one branch into another?

git merge <branch> — run while on the receiving branch, it integrates the named branch's changes into the current branch.

What is a fast-forward merge?

A merge where the target branch's tip is a direct ancestor of the source branch, so Git simply moves the pointer forward with no new merge commit and no divergent history.

What is a three-way merge?

A merge used when two branches have diverged. Git combines the two branch tips using their common ancestor as the base and creates a new merge commit with two parents.

What is a merge conflict and when does it occur?

A conflict occurs when two branches change the same lines of a file (or one edits a file the other deletes) so Git cannot auto-merge. The user must manually resolve the marked regions and commit the result.

What markers does Git insert into a file to indicate a merge conflict?

Conflict markers: <<<<<<< for the start of your current branch's version, ======= separating the two sides, and >>>>>>> marking the end of the incoming branch's version.

What is the difference between git merge and git rebase?

Merge creates a new commit that joins two histories, preserving the branching structure. Rebase replays your commits on top of another branch's tip, producing a linear history but rewriting commit hashes.

What is the golden rule of git rebase?

Never rebase commits that have been pushed to a shared/public branch, because rebasing rewrites history and would break collaborators who based work on the original commits.

What is a remote in Git?

A named reference (commonly origin) to another copy of the repository hosted elsewhere (e.g., on GitHub), used as the target for fetching and pushing changes.

What does git fetch do?

It downloads new commits, branches, and tags from a remote into your local repository's remote-tracking branches, but does NOT modify your working files or current branch.

What does git pull do, and what two operations does it combine?

It updates your current branch from the remote by running git fetch followed by git merge (or git rebase with --rebase) of the corresponding upstream branch.

What does git push do?

It uploads your local commits to a remote repository, updating the remote branch to match your local branch (e.g., git push origin main).

What is the difference between git fetch and git pull?

git fetch only downloads remote changes into remote-tracking branches without touching your working branch; git pull additionally merges (or rebases) those changes into your current branch.

What is the difference between git clone and git fork?

Cloning copies a repository to your local machine. Forking (a GitHub/host feature) creates your own server-side copy of someone else's repository under your account, which you can then clone and submit pull requests from.

What is an upstream (tracking) branch?

The remote branch that a local branch is configured to track (e.g., origin/main). It lets git pull and git push work without specifying the remote and branch each time, and powers ahead/behind status reporting.

What is a pull request (PR)?

A request on a hosting platform (e.g., GitHub) to merge changes from one branch (or fork) into another. It enables code review, discussion, automated checks, and approval before integration.

What is the typical pull request workflow?

Create a feature branch, commit and push changes, open a PR against the target branch, undergo review and CI checks, address feedback, get approval, then merge and delete the branch.

What are the main merge options when completing a pull request on GitHub?

Create a merge commit (preserves all commits plus a merge commit), Squash and merge (combines all PR commits into one), and Rebase and merge (replays commits linearly onto the base with no merge commit).

What is the difference between a merge commit and a squash merge in a PR?

A merge commit keeps every individual commit from the branch plus a new merge commit, preserving detailed history. A squash merge condenses all branch commits into a single commit on the base branch, giving a cleaner but less granular history.

What is the fork-and-pull-request model used in open-source collaboration?

A contributor forks the upstream repo, clones their fork, creates a branch, pushes changes to their fork, and opens a pull request to the original repository. Maintainers review and merge it.

What is a code review in the context of pull requests?

The process where collaborators inspect proposed changes for correctness, style, and quality, leaving comments, requesting changes, or approving before the code is merged.

How do you incorporate changes from the original repository into your fork (keeping it up to date)?

Add the original repo as a remote (often named upstream), then git fetch upstream and merge or rebase its branch into your local branch, and push to your fork.

What command lets you reapply a specific commit from one branch onto another?

git cherry-pick <commit-hash> — it copies the changes introduced by that single commit and applies them as a new commit on the current branch.

What is the difference between git reset and git revert for undoing commits?

git reset moves the branch pointer back, rewriting history and optionally discarding changes (dangerous on shared branches). git revert creates a new commit that undoes a previous commit's changes, keeping history intact and safe for shared branches.

What is git stash used for?

It temporarily shelves uncommitted changes (saving a clean working directory) so you can switch context or branches, then restore them later with git stash pop or git stash apply.

What is a tag in Git and how does it differ from a branch?

A tag is a fixed reference to a specific commit, typically marking release points (e.g., v1.0). Unlike a branch, a tag does not move as new commits are added.

What is the difference between a lightweight tag and an annotated tag?

A lightweight tag is just a named pointer to a commit. An annotated tag is a full Git object storing the tagger's name, email, date, a message, and an optional GPG signature, making it preferred for releases.