Poetry

$ poetry new my-project        # create a new package/project scaffold
$ cd my-project                # move into the project directory
$ poetry install               # create venv and install dependencies from lock/project
$ poetry shell                 # open a shell inside the Poetry virtualenv

$ poetry run python -m my_project  # run module with project virtualenv without activating shell

# runtime deps
$ poetry add requests                # add package to main dependencies and lock it

# dev deps
$ poetry add --group dev pytest ruff # add packages to dev group only

# remove
$ poetry remove requests             # remove dependency and update lock file

# update lock file with current constraints
$ poetry lock                     # resolve versions and regenerate poetry.lock

# install exactly what lock defines
$ poetry install --sync           # install exactly lock content, remove extra packages from venv

$ poetry show --tree               # display dependency tree with transitive dependencies
$ poetry env info                  # show current virtualenv path and interpreter info
$ poetry run pytest -q             # run tests using project virtualenv
$ poetry run python -V             # print Python version from project virtualenv

$ poetry self add poetry-plugin-export                                  # install export plugin in Poetry itself
$ poetry export -f requirements.txt --output requirements.txt --without-hashes  # generate pip-style requirements.txt