1.3. Core Git Concepts: Repositories, Commits, and Branches

If Git vs. GitHub is the first distinction the exam expects you to make cleanly, this is the second: the three nouns that every Git conversation is built from. Get these three confused and half the exam's scenario questions become guesswork, because nearly every GitHub feature — pull requests, forks, Actions triggers, branch protection — is really just a rule applied to one of these three things.

Picture a repository as a folder with a memory. Inside it, a commit is a labeled snapshot of that folder at one point in time, and a branch is simply a movable pointer to a particular sequence of those snapshots — a named line of history you can build up independently of everyone else's.

⚠️ Common Misconception: People frequently treat "committing" as synonymous with "saving to GitHub." A commit is entirely local until you explicitly push it — see 1.3.2 for why that distinction matters on exam day.