Git Basics in 15 Minutes

Git is version control: it keeps a history of your project as a series of snapshots called commits. You can look back at any snapshot, compare them, or return to one.

Git runs on your computer. GitHub (and similar sites like GitLab) store a copy online so you can back it up and share it.

git config --global user.name "Your Name"
git config --global user.email "you@example.com"

# start tracking a folder
cd my-project
git init

Files move through three places:

git status                       # what has changed?
git add index.html               # stage one file (or: git add .  for everything)
git commit -m "Add contact page"  # save the snapshot
git log --oneline                # see the history

Good commit messages say what the change does, in a few words: “Add contact page”, not “stuff” or “update”.

A branch is a separate line of work. Make one to try a new feature without touching the working version on main.

git switch -c new-header     # create a branch and move to it
# ...edit, add, commit as usual...
git switch main              # go back to main
git merge new-header         # bring the changes across

Merge conflicts happen when two branches changed the same lines. Git marks the clash in the file with <<<<<<< and >>>>>>>; keep the version you want, delete the markers, then add and commit.

git remote add origin https://github.com/you/my-project.git
git push -u origin main      # first time
git push                     # after that
git pull                     # get other people's changes
git clone https://github.com/someone/project.git   # copy a project

Never commit passwords or API keys. Once pushed, assume they're public. Add files like .env to a .gitignore file so Git ignores them.