The command inside
-R. Yes, exactly like the option on the command line.
- Followed by one of the command line option letters, this will change the setting of that option and print a message describing the new setting. If a ^P (CONTROL-P) is entered immediately after the dash, the setting of the option is changed but no message is printed. If
the option letter has a numeric value (such as
-b or -h), or a string value (such as -P or -t), a new value may be entered after the option letter. If no new value is
entered, a message describing the current setting
is printed and nothing is changed.
So by repeating
-R you will toggle displaying control characters (you may need to hit enter after each command).
For long format options you have
--+ resets short/long options to their default values. There are more similar commands: man less is your friend.