Git basics

Git is a version control system that tracks changes to your code over time. It lets you collaborate with others, experiment safely, and roll back mistakes.

Core Concepts

A repository (repo) is a folder tracked by Git. A commit is a saved snapshot of your changes. A branch is an independent line of development.

git init              # start tracking the current folder
git clone <url>       # copy an existing repo
git status            # see what has changed
git log --oneline     # view commit history

Making Commits

The basic Git workflow: edit files, stage your changes, then commit them.

git add index.html        # stage a specific file
git add .                 # stage all changes
git commit -m "Add nav"   # save a snapshot with a message

Writing Good Commit Messages

A good commit message is short, specific, and uses the imperative mood: "Add login form", not "Added login form" or "login stuff". Keep the subject under 72 characters.

# Good commit messages
git commit -m "Add responsive navbar"
git commit -m "Fix button hover color"
git commit -m "Remove unused CSS variables"
# Avoid vague messages like these
git commit -m "fix stuff"
git commit -m "update"
git commit -m "wip"

Working with Branches

Branches let you work on features without affecting the main codebase. Merge them back when ready.

git branch feature/nav      # create a new branch
git switch feature/nav      # switch to it
git switch -c feature/nav   # create and switch in one step
git merge feature/nav       # merge into current branch
git branch -d feature/nav   # delete after merging

Remote Repositories

Push and pull changes between your local repo and a remote like GitHub.

git remote add origin <url>   # link to a remote repo
git push origin main          # upload local commits
git pull origin main          # download remote commits

First push to GitHub

When pushing a new repo to GitHub for the first time, use the -u flag to set the upstream branch. After that, you can just use git push.

git push -u origin main   # first push — sets upstream
git push                  # all future pushes