Git Basics Reference

A practical reference for the Git commands you will use in this project. Bookmark this page.

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Core concepts

Concept	What it means
Repository (repo)	A folder tracked by Git — contains your project and its full history
Commit	A saved snapshot of your files at a point in time
Branch	An independent line of development — like a parallel version of the project
Remote	A copy of the repository hosted somewhere else (e.g. GitHub)
Fork	Your own copy of someone else's repository on GitHub
Pull Request (PR)	A proposal to merge your branch into another branch
Merge	Combining changes from one branch into another
Rebase	Replaying your commits on top of another branch (cleaner history than merge)

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Setting up Git

Configure your name and email (once, on any new computer):

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

Check your configuration:

git config --list

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Starting with a repository

Clone a repository to your local machine:

git clone https://github.com/USERNAME/REPO.git

Initialize a new repository in the current folder:

git init

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Working with remotes

View your remote connections:

git remote -v

Add a new remote:

git remote add upstream https://github.com/ORIGINAL/REPO.git

Fetch changes from a remote (does not merge):

git fetch upstream

Pull changes from a remote and merge:

git pull upstream main

Push your branch to your remote:

git push origin your-branch-name

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Branches

List all local branches:

git branch

List all branches including remote:

git branch -a

Create and switch to a new branch:

git checkout -b branch-name

Switch to an existing branch:

git checkout branch-name

Delete a branch (after it has been merged):

git branch -d branch-name

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Making changes

Check the status of your working directory:

git status

See what has changed (unstaged):

git diff

See what is staged and ready to commit:

git diff --staged

Stage specific files:

git add filename.html
git add folder/

Stage all changed files:

git add .

Unstage a file (keep changes, just remove from staging):

git restore --staged filename.html

Discard changes in a file (cannot be undone):

git restore filename.html

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Committing

Commit staged changes:

git commit -m "type: short description"

Amend the most recent commit message (before pushing):

git commit --amend -m "type: corrected description"

View commit history:

git log

View a compact commit history:

git log --oneline

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Rebasing

Rebase brings your branch up to date with another branch by replaying your commits on top of it.

First, fetch the latest changes:

git fetch upstream

Then rebase your branch onto main:

git rebase upstream/main

If there are conflicts, Git will pause and tell you which files conflict. Open them, resolve the conflict markers, then:

git add resolved-file.html
git rebase --continue

To abort a rebase in progress:

git rebase --abort

After rebasing, force-push your branch (required because history changed):

git push origin your-branch-name --force-with-lease

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Resolving merge conflicts

A conflict looks like this in a file:

<<<<<<< HEAD
your version of the line
=======
the incoming version of the line
>>>>>>> upstream/main

To resolve:

1. Open the conflicted file in your editor
2. Decide which version to keep (or combine them)
3. Delete the conflict markers (<<<<<<<, =======, >>>>>>>)
4. Save the file
5. Stage it: git add filename
6. Continue the merge or rebase

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Useful shortcuts

Undo the last commit (keep changes staged):

git reset --soft HEAD~1

Stash uncommitted changes (to work on something else temporarily):

git stash

Restore stashed changes:

git stash pop

See the full history with branches visualized:

git log --oneline --graph --all

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Common mistakes and fixes

Committed to main by accident

git checkout -b my-branch       # create a new branch at current state
git checkout main               # go back to main
git reset --hard origin/main    # reset main to match remote
git checkout my-branch          # continue work on the new branch

Pushed the wrong thing

Do not force-push to main. Contact a maintainer.

Forgot to pull before starting work

git fetch upstream
git rebase upstream/main

This replays your commits on top of the latest main.