Sort of a playground app - learning more about Swift on the command-line, targeted towards running on a Raspberry Pi. End goal is an app that communicates with different processes on the Pi.
Uses Swift 5.1 as there isn't Swift 5.2 support on the Pi quite yet.
Using some of the info picked up here for initial project setup: https://www.swiftbysundell.com/articles/building-a-command-line-tool-using-the-swift-package-manager/
Fire it up using:
swift run SerialPi [ process | port | file ]
(Something is likely to go wrong.)