The bash shell in macos Catalina has been demoted to the subs bench with the newer zsh shell is now the default shell in use by the new operating system. Also known as the Z shell, it has been around a while, since 1990 (bash was 1988), it is still a Unix based shell and should be easily transitioned to from the old bash one as they share a common foundation.

The Bash shell will ultimately be dropped from the macos core.

To run scripts in zsh shell, similar to .bash_profile or .bashrc,  create a home directory file named ‘.zshrc‘ and add the scripts, paths, alias etc

To see all available shells in macos Catalina run…

cat /etc/shells

To change to bash shell

chsh -s /bin/bash

Relaunch Terminal or iTerm

To swap back to zsh shell

chsh -s /bin/zsh

Relaunch Terminal or iTerm