macOS Software Versioning and Updating from the command-line

Over and above the usual way to determine the Mac's software levels : -

 > About This Mac

and Software Update : -

we also have the command line: -

sw_vers 

ProductName: Mac OS X
ProductVersion: 10.15.7
BuildVersion: 19H15

and: -

softwareupdate -l

Software Update Tool
Finding available software
No new software available.

Getting ready for Big Sur, in case you couldn't tell 😂