Q: Find only CR files (mac only) How can I grep only files with CR line return (excluding CRLF and LF)?
With grep -rl $'\r' * I find both CRLF and CR, while with grep -rl $'\n' * I find all LF.
Maybe I can do an exclusion?

A: You have to exclude matches of an additional \n found immediately after a \r to filter out those: 
$> grep -rl $'\\r[^\\n]'

Note the double \\, apparently the usual backslash notation has to be escaped to "survive" the shell interpretation before getting fed into the actual grep command. 
