This guide assumes you already have python and pip installed.
To install pytube, run the following command in your terminal:
$ pip install pytube
pytube is actively developed on GitHub, where the source is available.
You can either clone the public repository:
$ git clone git://github.com/pytube/pytube.git
Or, download the tarball:
$ curl -OL https://github.com/pytube/pytube/tarball/master
# optionally, zipball is also available (for Windows users).
Once you have a copy of the source, you can embed it in your Python package, or install it into your site-packages by running:
$ cd pytube
$ python -m pip install .
原文：https://www.cnblogs.com/lishidefengchen/p/15232693.html