In zsh (the default shell in MacOS), R launches the R programming language console.
r, in contrast, does ... what?
% which r
r: shell built-in command
% man r
No manual entry for r
I can't figure out how to do a web search for this one without getting results for R instead of r.
Follow
Per [`man zshbuiltins`](https://linux.die.net/man/1/zshbuiltins), the builtin shell command `r` is equivalent to `fc -e -`, which, to my reading of the same manpage, selects the most recent command and executes it without editing.
