Python Toolchain

Common commands for Python projects.

Virtual environments

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

# Poetry
poetry install
poetry shell
poetry add requests
poetry add --group dev pytest

# uv (fast)
uv venv
uv pip install -r requirements.txt
uv pip install requests

Testing

# pytest
python3 -m pytest
python3 -m pytest -v --tb=short
python3 -m pytest tests/test_api.py -k "test_login"
python3 -m pytest --cov=src --cov-report=term-missing

# unittest
python3 -m unittest discover -s tests

Linting & formatting

# Ruff (fast, replaces flake8+isort+black)
ruff check .
ruff check --fix .
ruff format .

# Black
black .

# Mypy (type checking)
mypy src/

Running

python3 src/main.py
python3 -m mypackage

# Flask
flask run --debug

# Django
python3 manage.py runserver
python3 manage.py migrate
python3 manage.py createsuperuser

Debugging

python3 -m pdb src/main.py         # PDB debugger
python3 -c "import sys; print(sys.version)"
python3 -c "import pkg; print(pkg.__version__)"

Packaging

pip install build
python3 -m build                    # Build wheel + sdist
pip install -e .                    # Editable install

Dependencies

pip list --outdated
pip freeze > requirements.txt
pip-audit                           # Security audit

Notes

• Check for pyproject.toml, setup.py, or requirements.txt to understand project structure.
• Prefer virtual environments to avoid global package conflicts.
• Use python3 explicitly (not python) for portability.