sudo port install bash && echo /usr/local/bin/bash | sudo tee -a /etc/shells && chsh -s /usr/local/bin/bash
... and then you run a script that depends on `/bin/bash` .. but uses a feature (e.g. coproc, associative arrays) from a version less than a decade old. And then you go and update your PATH and shebang lines to call out `/usr/bin/env bash` and hope things go right.
Something like that, but they changed the default shell to zsh, which is newer.
I thank Apple for going to zsh- forcing me to begin learning it and now I have it on all my mzchiesn.
I find your misspelling of "machines" charming.
I am continually boggled by what my iPhone corrects and doesn’t correct.
I prefer linux, but it is quite easy to install different shells on macOS.