Following on from my earlier post: -
reflecting the fact that macOS 12.1 Monterey still includes Bash 3.X: -
GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin21)
Copyright (C) 2007 Free Software Foundation, Inc.
I noticed that one can use Homebrew to install Bash 5.X: -
brew install bash
which gives us: -
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.