Git

In simple terms

Git is the most-used tool for tracking changes to code. You take snapshots (“commits”), give them messages, group them on branches, and share them with other people through a remote server like GitHub or GitLab.

More detail

Git was created by Linus Torvalds in 2005 to coordinate development of the Linux kernel. Its key ideas:

• A repository is a directed graph of commits. Each commit points to the snapshot it captured and to one or more parents.
• Branches are just movable pointers into that graph.
• Every clone has the full history, not just the latest revision.
• Most operations are local and fast.

The day-to-day commands you use most:

Command	Roughly does
git clone <url>	Copy a remote repo locally
git status / git diff	See what is changed
git add <files> / git commit -m "..."	Stage and record changes
git push / git pull	Sync with the remote
git checkout -b <branch>	Make and switch to a new branch
git merge / git rebase	Combine branches

Why it matters

Git is the lingua franca of modern software development. Almost any open-source contribution today flows through it.

Real-world examples

• The Linux kernel.

• Practically every open-source library on GitHub.

• This very project.

• git bisect can find a regression-introducing commit across thousands of commits in log₂(n) steps — a real-world application of binary search you’ll use as soon as you have one bug.

Common misconceptions

• “git push --force is fine.” It is fine on your own branch; it rewrites public history on shared branches and is one of the most reliable ways to upset your teammates.
• “git pull is harmless.” git pull is fetch + merge. It can leave you with merge commits or conflicts you didn’t expect.

Learn next

GitHub, code review, branching strategies (trunk-based development, GitHub flow, etc.).