Daily pip Commands (with venv)

The single most important pip habit is never install packages globally. Always work inside a virtual environment (venv) per project. The four commands you'll type most are venv setup, install, freeze, and run.

python3 -m venv .venv creates a virtual environment in a .venv directory. source .venv/bin/activate activates it — your shell prompt prefixes with (.venv) and which python now points inside the venv. deactivate exits.

Inside the venv: pip install <pkg> installs a package into this venv only. pip install -r requirements.txt installs from a requirements file. pip install -e . does an editable install of the current directory — changes to source code take effect immediately, the standard way to develop a Python package.

pip freeze outputs every installed package in name==version format — the closest pip gets to a lockfile. Redirect to requirements.txt to capture your environment. pip list shows installed packages in a table format. pip show <pkg> shows version, install location, dependencies, and homepage for one package. pip uninstall <pkg> removes one (but does NOT remove its now-orphaned dependencies — that's pip's dirty-uninstall problem).

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The venv-first workflow·bash

# 1. Per-project venv
cd my-project
python3 -m venv .venv

# 2. Activate (zsh / bash)
source .venv/bin/activate

# Now your prompt shows (.venv); python and pip point inside the venv
which python
# /Users/you/my-project/.venv/bin/python

# 3. Install
pip install requests flask

# 4. Capture state
pip freeze > requirements.txt

# 5. Deactivate when done
deactivate

Reproduce on another machine·bash

# Clone the project; teammate's setup
cd my-project
python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

# Now they have the same packages — but NOT necessarily the same
# transitive dep versions, unless requirements.txt was generated by
# a true locking tool like pip-tools, pip-compile, or uv.

Editable install for library development·bash

# In a Python package's source dir (with pyproject.toml or setup.py)
pip install -e .

# Now the package is importable from anywhere in this venv,
# AND your code edits take effect immediately — no reinstall needed.
# Standard workflow when developing a library.

Daily pip Commands (with venv)

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