-dit(bf(-b, --backup)) With this option preexisting destination files are
-renamed with a ~ extension as each file is transferred. You can
-control the backup suffix using the --suffix option.
+dit(bf(-b, --backup)) With this option, preexisting destination files are
+renamed as each file is transferred or deleted. You can control where the
+backup file goes and what (if any) suffix gets appended using the
+--backup-dir and --suffix options.