GitHub¶

Written: 2026-08-23

Overview¶

GitHub — the world's largest code hosting platform. Beyond Git repositories, it provides CI/CD (Actions), project management (Issues/Projects), package registry, and collaboration tools.

Core Concepts¶

Concept	Purpose
Repository	Project container (code, history, config)
Branch	Isolated line of development
Pull Request (PR)	Propose + review + merge changes
Issue	Track bugs, features, tasks
Actions	CI/CD workflows (YAML-defined)
Projects	Kanban boards for planning
Releases	Versioned artifacts with changelogs
Packages	Container/package registry

GitHub CLI (gh)¶

Installation¶

# macOS
brew install gh

# Linux (Debian/Ubuntu)
sudo apt install gh

# Authenticate
gh auth login

Essential Commands¶

Command	Purpose
`gh repo clone owner/repo`	Clone repository
`gh repo create name --public`	Create new repo
`gh pr create --fill`	Create PR from current branch
`gh pr list`	List open PRs
`gh pr checkout 42`	Check out PR #42 locally
`gh pr merge 42 --squash`	Squash-merge PR
`gh issue create --title "Bug"`	Create issue
`gh issue list --label bug`	List bugs
`gh run list`	List workflow runs
`gh run watch`	Watch current workflow
`gh release create v1.0`	Create release

GitHub Actions (CI/CD)¶

Basic Workflow¶

# .github/workflows/ci.yml
name: CI
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: '3.12'
      - run: pip install -r requirements.txt
      - run: pytest --tb=short

Useful Actions¶

Action	Purpose
`actions/checkout@v4`	Check out repo
`actions/setup-python@v5`	Install Python
`actions/setup-node@v4`	Install Node.js
`actions/cache@v4`	Cache dependencies
`actions/upload-artifact@v4`	Save build artifacts
`github/codeql-action`	Security scanning
`softprops/action-gh-release`	Auto-create releases

Branch Protection Rules¶

Rule	Effect
Require PR reviews	No direct push to main
Require status checks	CI must pass before merge
Require linear history	Squash or rebase only (no merge commits)
Require signed commits	GPG signature required
Restrict push access	Only specific teams can push

Tips¶

Tip	How
Quick file edit	Press `.` on any repo page → open in web editor
Search code	`repo:owner/name language:python "pattern"`
Keyboard shortcuts	Press `?` on any GitHub page
Draft PRs	Create PR as draft → mark ready when done
Auto-close issues	PR description: `Fixes #42` or `Closes #42`
CODEOWNERS	`.github/CODEOWNERS` → auto-assign reviewers
Dependabot	`.github/dependabot.yml` → auto-update deps
Templates	`.github/PULL_REQUEST_TEMPLATE.md`