A character string has the value false if it is 0, and true if it is 1. The logical operators take one or two such values and return 0 or 1 as appropriate. Values other than 0 or 1 are not permitted.
&
AND — returns 1 if both terms are true.
|
Inclusive OR — returns 1 if either term or both terms are true.
&&
Exclusive OR — returns 1 if either term, but not both terms, is true.
Prefix \, ¬
Logical NOT— negates; 1 becomes 0, and 0 becomes 1.
