After installing python3 with brew install python3
I was getting the error:
Error: An unexpected error occurred during the `brew link` step
The formula built, but is not symlinked into /usr/local
Permission denied @ dir_s_mkdir - /usr/local/Frameworks
Error: Permission denied @ dir_s_mkdir - /usr/local/Frameworks
After typing brew link python3 the error was:
Linking /usr/local/Cellar/python/3.6.4_3... Error: Permission denied @ dir_s_mkdir - /usr/local/Frameworks
To solve the problem:
sudo mkdir -p /usr/local/Frameworks
sudo chown -R $(whoami) /usr/local/*
brew link python3
After this, I could open python3 by typing python3 👍
(From https://github.com/Homebrew/homebrew-core/issues/20985)