Pip and other aliases in Mac Catalina / ZSH

Mac Catalina uses ZSH by default. Which is what you'll get if you buy a new Mac.
If you follow the guide, https://docs.python-guide.org/starting/install3/osx/#pipenv-virtual-environments, at the end, if you just run "pip" in your terminal, it will not be found.

After I changed the default terminal to bash, and reinstalled python with brew, then running "pip --version" gives pip version 3 as expected.

從連結的 Python Guide URL 中 macOS 的 pipenv 虛擬環境部分開始，並在 Catalina 的預設 ZSH shell 中重現文件中的命令。檢查回報的 pip 命令，以及它與 Bash 和 Homebrew 的差異；完成標準是該指南解釋或解決新 macOS 使用者缺少 pip 別名的問題。