Install Python 3 Macos Catalina


Installing OpenCV in MacOS Catalina for Python 3 (2019). Step 3: Install the Anaconda Python Package. Download File from here. Click on python 3 version and download it. In my system, you would see the following outputs. [email protected] % type python. Python is /usr/bin/python. Take python as an example. It tells you /usr/bin/python is called when you use the command python. However, the path is not necessarily your interpreter's real path: it may be an alias or a trampoline.

When I reinstalled my iMac with macOS Catalina in January 2020 I stubbled upon a error that I had seen before but I convenience ignored every time it popped-up. The first time I read it I thought I will fix it when I need to. But now I can’t ignore it anymore. the message I saw in my terminal was:


Time to take a deeper look at this upgrade of Pyton to Python 3 and how to solve the problems that come with it.

Python 3

Historically MacOS came preinstalled with Python 2, however starting with macOS Catalina 10.15 (released in October 2019) this is no longer the case. And since Python 2 will no longer be officially supported as of January 1, 2020, you should really use Python 3 instead.

There are multiple ways to install Python 3 on a MacOS computer. The official Python website even recommends downloading it directly, however this approach can cause confusion around PATH variables, updates, and uninstalls. A better approach, in my opinion, is to instead use the popular package manager Homebrew which automates updates and juggling multiple versions of Python on a computer.

Check Python version

Before we start, make sure Python 3 isn’t already installed on your computer. Open the Terminal app. Click the Finder icon in your dock. Click Go. Click Utilities. Double-click Terminal.

Then type the command

Install python3 macos catalina

followed by the Enter key to see the currently installed version of Python.

Note: The percent sign, (%), indicates user input. Everything after is intended to be typed by the user followed by the Enter key. Any output, such as Python 2.7.17 in this case, does not have a dollar sign in front. In short: don’t type % before your commands!

It’s possible that Python 3 may have already been installed as python3. Run the command

to check, however most likely this will throw an error.

Install XCode

The first step for Python 3 is to install Apple’s Xcode program which is necessary for iOS development as well as most programming tasks. We will use XCode to install Homebrew.

In your Terminal app, run the following command to install XCode and its command-line tools:

It is a large program so this make take a while to download. Make sure to click through all the confirmation prompts XCode requires.

Install Homebrew

Next install Homebrew by copy/pasting the following command into Terminal and then type Enter:

To confirm Homebrew installed correctly, run this command:

Install Python 3

Now we can install the latest version of Python 3. Type the following command into Terminal and press Enter:

To confirm which version of Python 3 was installed, run the following command in Terminal:

Finally, to run our new version of Python 3 open an interactive shall by typing python3 within Terminal:

To exit the Python 3 interactive shell, you can type either exit() and then Return or type Control+d which means hold both the Control and D keys at the same time.

Note:It is still possible to run Python 2 by simply typing python:


How do I change the default version of Python on Mac?

Open the terminal (bash or zsh) whatever shell you are using. Install python-3 using Homebrew (https://brew.sh). Look where it is installed. Change the default python symlink to the version you want to use from above.

How do I know what version of Python I have Mac?

To do this, open the Applications folder in Finder, double-click the Utilities folder, then double-click Terminal. Type python -V at the prompt (V uppercase). Press ⏎ Return . The version number will appear on the next line after the word “Python” (e.g. 2.7.

Where is Python installed on Mac?

The Apple-provided build of Python is installed in /System/Library/Frameworks/Python.

How do I update Python on Mac terminal?

  1. brew install python –> install the latest Python.
  2. ls -l /usr/local/bin/python* –> List all Python versions installed on your system.
  3. ln -s -f /usr/local/bin/python[your-latest-version-just-installed] /usr/local/bin/python –> Change default Python version to the latest version.

How do I install Python on Mac Catalina?

Installing Python 3 in Mac OS

  1. run python –version and you’ll find that it is some version of python 2.7 then run pip -version and you’ll find that it is some version of python 2.7 pip .
  2. run brew install python3.
  3. run brew postinstall python3 in order to install pip3 the latest package manager.

What is Xcode on Mac?

Install Python 3 Mac Os Catalina Update

Install Python 3 Macos Catalina

Xcode is Apple’s integrated development environment (IDE) for macOS, used to develop software for macOS, iOS, iPadOS, watchOS, and tvOS. Xcode includes Command Line Tools (CLT), which enable UNIX-style development via the Terminal app in macOS.

How do I download Xcode on an old Mac?

Older versions of Xcode can be found by logging into the Apple Developer Downloads page and searching for the version of Xcode you need.

Can I download older versions of Mac OS?

Install Python 3 Mac Os Catalina Os

The version of macOS that came with your Mac is the earliest version it can use. For example, if your Mac came with macOS Big Sur, it will not accept installation of macOS Catalina or earlier. If a macOS can’t be used on your Mac, the App Store or installer will let you know.

Can I download an earlier version of iOS?

Apple generally stops signing the previous version of iOS a few days after a new version is released. This means that it’s often possible to downgrade back to your previous version of iOS for a few days after you upgrade — assuming the latest version was just released and you upgraded to it quickly.

How do I install an older version of iOS on Mac?

Here are the steps Apple describes:

Install Python 3 Mac Os Catalina Download

  1. Start up your Mac pressing Shift-Option/Alt-Command-R.
  2. Once you see the macOS Utilities screen choose the Reinstall macOS option.
  3. Click Continue and follow the on-screen instructions.
  4. Select your startup disk and click Install.
  5. Your Mac will restart once the installation is complete.

How do I roll back my Mac update?

Question: Q: How do I roll back an OS update?

  1. Shut down your Mac, and restart it using macOS Internet Recovery.
  2. Then, select Disk Utility to completely erase your startup volume.
  3. Then, select Reinstall OS X.
  4. Install that version of OS X, following its instructions.
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