Pip (package manager)


pip is a de facto standard package-management system used to install and manage software packages written in Python. Many packages can be found in the default source for packages and their dependencies — Python Package Index.
Most distributions of Python come with pip preinstalled. Python 2.7.9 and later, and Python 3.4 and later include pip by default.
First introduced as pyinstall in 2008 by Ian Bicking as an alternative to easy_install, pip was chosen as the new name from one of several suggestions that the creator received on his blog post. According to Bicking himself, the name is an acronym for "Pip Installs Packages". In 2011, the was created to take over the maintenance of pip and virtualenv from Bicking, led by Carl Meyer, Brian Rosner, and Jannis Leidel.

Command-line interface

One major advantage of pip is the ease of its command-line interface, which makes installing Python software packages as easy as issuing a command:

pip install some-package-name

Users can also easily remove the package:

pip uninstall some-package-name

Most importantly pip has a feature to manage full lists of packages and corresponding version numbers, possible through a "requirements" file. This permits the efficient re-creation of an entire group of packages in a separate environment or virtual environment. This can be achieved with a properly formatted file and the following command, where requirements.txt is the name of the file:

pip install -r requirements.txt

Install some package for a specific version python, where $ is replaced for 2, 3, 3.4, etc.:

pip$ install some-package-name