Python Tutorial, Release 3.9.5 (tutorial-env )$ pip show requests --- Metadata-Version:2.0 Name: requests Version: 2.7.0 Summary: Python HTTP for Humans. Home-page: http://python-requests.org Author: Kenneth Reitz Author-email: me@kennethreitz.com License: Apache 2.0 Location: /Users/akuchling/envs/tutorial-env/lib/python3.4/site-packages Requires: (tutorial-env )$ pip list novas(3.1.1.3 ) numpy(1.9.2 ) pip (7.0.3 ) requests (2.7.0 ) setuptools(16 .0 ) (tutorial-env )$ pip freeze > requirements.txt (tutorial-env )$ cat requirements.txt novas==3.1.1.3 numpy==1.9.2 requests==2.7.0 (tutorial-env )$ python -m pip install -r requirements.txt Collectingnovas==3.1.1.3 (from -r requirements.txt (line 1)) ... Collectingnumpy==1.9.2 (from -r requirements.txt (line 2)) ... Collectingrequests==2.7.0 (from -r requirements.txt (line 3)) ... Installing collected packages: novas, numpy, requests Running setup.py install for novas Successfully installed novas-3.1.1.3 numpy-1.9.2 requests-2.7.0 93 12.3. Managing Packages with pip $_{pip}$has many more options. Consult the installing-index guide for complete documentation for$_{pip}$ . When you’ve written a package and want to make it available on the Python Package Index, consult the distributing-index guide. The$_{requirements.txt}$ can then be committed to version control and shipped as part of an application. Users can then install all the necessary packages with$_{install -r}$ : pip freeze will produce a similar list of the installed packages, but the output uses the format that pip install expects. A common convention is to put this list in a$_{requirements.txt}$ file: pip list will display all of the packages installed in the virtual environment: