Git Tutorial Basics

Git is a distributed version control system. Instead of relying on a single central server, each developer clones a full copy of the repository (including history) to their local machine. The original repository can live on a self-hosted server or a hosting service like GitHub.

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Step 0: Create a GitHub Account

Sign up at: https://github.com/

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Step 1: Make sure Git is installed

macOS / Linux / Windows (Git Bash / PowerShell):

git --version

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Step 2: Tell Git who you are

Every commit records your name and email.

git config --global user.name  "Your_UserName"
git config --global user.email "you@example.com"
git config --global init.defaultBranch main
git config --global --list   # verify settings

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Step 3: Create a repository (GitHub → New)

Follow GitHub’s guide: https://docs.github.com/en/repositories/creating-and-managing-repositories/creating-a-new-repository

Tip: Create it empty (no README/license) to avoid merge conflicts on your first push.

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Step 4: Initialize a local repo and add files

Navigate to the folder you want under Git, then initialize:

cd ~/Desktop/your_directory
git init
touch README.md
echo "My first repo" >> README.md

Stage and commit:

git add .
git commit -m "First commit"

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Step 5: Connect your local repo to GitHub

⚠️ Important: GitHub no longer supports password authentication for Git operations. You must use either a Personal Access Token (PAT) or SSH key.

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Option 1 — HTTPS with a Personal Access Token (PAT)

1. Generate a Personal Access Token (PAT):

   • Go to: https://github.com/settings/tokens
   • Choose Fine-grained token (recommended) or Classic token
   • Scope: allow repo (read and write)

2. Set the remote:

   git remote add origin https://github.com/<your-username>/<repo-name>.git

3. Push your local commits:

   git branch -M main
   git push -u origin main

4. When prompted:

   • Username: your GitHub username (e.g., sudipdhakal1)
   • Password: your PAT (paste the token here; you won’t see it on screen)

5. (Optional) To store your token securely on macOS:

   git config --global credential.helper osxkeychain

🔒 Never paste your token directly into commands or share it. If you ever expose your token, revoke it immediately in GitHub settings and generate a new one.

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Option 2 — SSH (recommended for long-term use)

Generate an SSH key and add it to GitHub:

ssh-keygen -t ed25519 -C "you@example.com"
eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519

Copy the public key to GitHub:

pbcopy < ~/.ssh/id_ed25519.pub  # macOS
# or clip < ~/.ssh/id_ed25519.pub (Windows)

Then set your remote and push:

git remote add origin git@github.com:<your-username>/<repo-name>.git
git branch -M main
git push -u origin main

Test connection:

ssh -T git@github.com

If successful, you’ll see:

Hi <username>! You've successfully authenticated.

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Change the remote URL later (if needed)

git remote -v                     # verify current
git remote set-url origin <new-url>

Examples:

# switch to HTTPS
git remote set-url origin https://github.com/<your-username>/<repo-name>.git

# switch to SSH
git remote set-url origin git@github.com:<your-username>/<repo-name>.git

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Clone an existing GitHub repo

On GitHub, click Code → copy the HTTPS or SSH URL, then:

cd /path/to/your/folder
git clone https://github.com/<username>/<repository-name>.git
cd <repository-name>

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Everyday workflow (edit → stage → commit → push)

git status
git add -A
git commit -m "Describe what changed"
git push

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Collaboration Basics

Invite a collaborator:

• Go to your repo → Settings → Collaborators → Add people

Work on a branch:

git checkout -b feature/update-readme
git add .
git commit -m "Updated README with secure token instructions"
git push -u origin feature/update-readme

Then open a Pull Request on GitHub to merge changes into main.

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Helpful tips

If your local and remote branches differ (e.g., GitHub created a README online):

git pull --rebase origin main
git push

Handle line endings:

# Windows
git config --global core.autocrlf true

# macOS/Linux
git config --global core.autocrlf input

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Handling Merge Conflicts

If you see conflict markers like:

<<<<<<< HEAD
...
=======
...
>>>>>>> some-commit-hash

Edit to keep the correct content, then:

git add <file>
git commit -m "Resolve merge conflict"