Last week I decided to finally upgrade my macOS BigSur to Sonoma. As usual I get issues after the upgrade. For example, security settings, apps permissions, custom backup script I put together to backup my files to a NAS drive stop working. This time I got error “Python3.9: bad interpreter: No such file or directory“.

I usually play around with Docker for personal projects and to improve my skills. I was working on a Python/Flask/SQLAlchemy app and decided to use my native python instead of creating another container in Docker. To solve the error above I did the following: (after brewing a great cup of coffee from Peru at home of course!)

  1. Installed Homebrew
  2. After installing Homebrew I ran: brew install pyenv

Next, you can use pyenv to manage your python versions – Very cool! Use the below command for example:

pyenv install 3.9.2 

If you desire a different version do:

pyenv install 4.x.x

Remember, you need to have macOS Xcode/Developer tools installed on your mac before having Homebrew.

Final steps – Update your bash_profile(I still use bash instead of zsh – yes!):

echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bash_profile
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bash_profile

If you do not have a /bin directory in your pyenv_root folder (you may only have a /shims directory) you may need to instead run this version of the command:

`echo 'export PATH="$PYENV_ROOT/shims:$PATH"' >> ~/.bash_profile`

Add pyenv to your Terminal:

echo -e 'if command -v pyenv 1>/dev/null 2>&1; then\n  eval "$(pyenv init -)"\nfi' >> ~/.bash_profile

And finally, reset your Terminal:


I need to thank freeCodeCamp for the reference above. Again, you can contact me if you have any questions or if you like to collaborate. Also, check out my designs below

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