`cp`: `-r` or `-R`?

blog - git - desktop - contact 2026-09-30 A question like this recently came up again. I once tried to find an answer, but only posted it in some "forum" a decade ago, and I think it's worth saving this little bit of trivia from digital nirvana. Nowadays, there's no difference between the two options in GNU coreutils. The current manual page says: -R, -r, --recursive copy directories recursively Was that always the case? Let's look at the first commit in GNU coreutils (1992). In src/cp.c, we have this: case 'r': flag_recursive = 1; flag_copy_as_regular = 1; break; case 'R': flag_recursive = 1; flag_copy_as_regular = 0; break; So, back then, there was indeed a difference. But that was 34 years ago. Is that still relevant today? Probably not, because ten years later, in 2002, both options got merged and nobody™ still runs coreutils from 24 years ago. What about other systems? OpenBSD 7.9 lists only -R in the manual and strongly discourages the use of -r. It does mention, though, that it still behaves differently than -R. Skim through the code and you can spot a few differences (search for Rflag and rflag). NetBSD 11: Dito, manual page and code like OpenBSD. The advantage of -R is that it's more consistent across utilities. For example, chown knows -R -- but not -r. POSIX acknowledges this as well and recommends -R: Earlier versions of this standard included support for the -r option to copy file hierarchies. The -r option is historical practice on BSD and BSD-derived systems. This option is no longer specified by POSIX.1-2024 but may be present in some implementations. The -R option was added as a close synonym to the -r option, selected for consistency with all other options in this volume of POSIX.1-2024 that do recursive directory descent.