While reading the help information I saw that the -f option depends on the -d option being present.
I think rcuts should try to infer the delimiter if the -d flag is not present. typical delimiters include spaces, tabs and commas but I think more complex separators could eventually be detected. Of course -d should never be overwritten.

I am not sure how far this repo is allowed/expected to deviate from GNU cut if the goal is simply to be the same with UTF-8 support then this issue will be out of scope.

I am happy to start talking about how we could achieve this, if this idea is ok in principal.