https://www.theregister.co.uk/2019/06/04/apple_zsh_macos_catalina_default/

For the past decade, Apple has avoided updating the Bourne Again SHell, better known as bash, for its desktop operating system due to the iGiant's distaste for the GPLv3 license attached to the command interpreter.

Now, the fondleslab slinger has finally made the fancier Z shell, zsh, the default login and interactive shell in its forthcoming macOS 10.15 aka Catalina.