The following instructions focus on getting Python 3 running on Debian/Ubuntu Linux-based systems as well as on macOS via MacPorts or HomeBrew.
Tip: If you are running on an Intel-based computers (e.g., most Macs and Windows machines), you can use a Python distribution called Miniconda. This is often the easiest approach to getting Python on your machine. If that's not suitable for you for any reason, continue reading!
It may be possible to use the default copy of Python provided by your operating system if it happens to be a version 3 edition of Python. As of January 2021, the oldest still-supported version of Python is 3.6. However, for historical reasons, many operating system distributions still ship with Python version 2.7 even today. This can be confusing, because the default python and pip commands provided on these operating systems is version 2.7 of Python; attempting to run programs written for Python version 3 with version 2.7 can result in extremely confusing errors that bear no relationship to the actual problem, which is that the program is not written to run in Python 2.7.
On some systems, version 3.x of the Python interpreter and pip are available using the commands python3 and pip3, respectively. More often, they must be installed separately. The following subsections describe how Python 3 can be installed either using the standard software package managers on certain popular operating systems, or using third-party software managers.
Debian-based systems still ship with older versions of Python by
default. To install a modern version of Python and the associated version of pip, run the following command:
sudo apt install python3 python3-pip
The version of Python that comes with macOS through at least macOS 10.15 (Catalina) is Python 2.7. The most convenient way to get Python 3.x and the associated version of pip is to use MacPorts or HomeBrew, depending on your preference.
If you are using macOS and MacPorts, the following command will install a recent version of Python 3:
sudo port install python3 py38-pip
After running the command above, you should be able to invoke the Python interpreter using the command python3. You can verify the version of Python and pip with the following commands:
python3 --version
python3 -m pip --version
If you are using HomeBrew, the corresponding commands are as follows:
brew install python3
HomeBrew's Python 3 package installs pip3 by default. Unless you configured your copy of HomeBrew to install it elsewhere, programs should end up in /usr/local/bin on your computer. Look for pip3 there (e.g., by running the command ls /usr/local/bin/pip* to see what gets listed).