I'm more inclined to use the uppercase -R as it's standardized by POSIX and will generally behave the same on any POSIX compliant system.
I'm more inclined to use the uppercase -R as it's standardized by POSIX and will generally behave the same on any POSIX compliant system.
It's also the only option shown in the -h output and in man pages for some versions of cp.
I didn't even know -r was a thing until today.