13. Handy Commands

Small command-line recipes for virtualenvs, quality checks, and ad-hoc servers.

# Create and use a virtual environment
python3 -m venv .venv
source .venv/bin/activate
python -m pip install --upgrade pip
pip install -r requirements.txt

# Freeze/update dependencies
pip freeze > requirements.txt

# Quality toolchain (install as needed)
pytest -q
ruff check .
ruff format .
mypy .

# Quick local web server (serve current dir)
python -m http.server 8000

# Inspect installed packages
python -m pip list