Python Package Installer (PIP)
Introduction
Pip is a package-management system written in Python and is used to install and manage software packages. The Python Software Foundation recommends using pip for installing Python applications and its dependencies during deployment.
Command Line Basics
PIP is most commonly used on the command line.
There are two ways to invoke pip.
Invoke PIP through PATH
The first way is to invoke pip through the command line environment's
PATH variable.
Most of the time, this will include a directory that contains the pip
program to run.
Typically this will be the operating system default version of python.
So this should be reserved for system-wide installations or
when using a virtual environment.
Invoke PIP through Python Module
PIP itself is actually a python module. So it can be invoked through the python interpreter.
python3.5 -m pip install --upgrade pipThe benefit of this approach is that you can explicitly state which version of python to use. This means that the packages installed will be available to that version of python. It also means that those versions of packages are only available to that version of python, segregating the packages from other versions of python.