pip is your friend when you need to install any package from the plethora of choices available at the python package index (PyPI). pip is already installed if you’re using Python 2 >= 2.7.9 or Python 3 >= 3.4 downloaded from python.org. For computers running Linux or another *nix with a native package manager, pip must often be manually installed.

On instances with both Python 2 and Python 3 installed, pip often refers to Python 2 and pip3 to Python 3. Using pip will only install packages for Python 2 and pip3 will only install packages for Python 3.

Finding / installing a package

Searching for a package is as simple as typing

$ pip search <query>
# Searches for packages whose name or summary contains <query>

Installing a package is as simple as typing (in a terminal / command-prompt, not in the Python interpreter)

$ pip install [package_name]           # latest version of the package

$ pip install [package_name]==x.x.x    # specific version of the package

$ pip install '[package_name]>=x.x.x'  # minimum version of the package

where x.x.x is the version number of the package you want to install.

When your server is behind proxy, you can install package by using below command:

$ pip --proxy http://<server address>:<port> install

Upgrading installed packages

When new versions of installed packages appear they are not automatically installed to your system. To get an overview of which of your installed packages have become outdated, run:

$ pip list --outdated

To upgrade a specific package use

$ pip install [package_name] --upgrade

Updating all outdated packages is not a standard functionality of pip.

Upgrading pip

You can upgrade your existing pip installation by using the following commands

• On Linux or macOS X:

  $ pip install -U pip

You may need to use `sudo` with pip on some Linux Systems

• On Windows:

  py -m pip install -U pip

  or

  python -m pip install -U pip

For more information regarding pip do read here.