The negating exclamation mark ! is used to create the next set of meta-operators. If it is prepended to the existing operator op, you get the operator that gives you the negated result !op.
say "no" if "abcd" !~~ "e";
📘 Negation meta-operator ! in Raku
N. B. Perl 6 has been renamed to Raku. Click to read more.