The comparison operators compare two terms and return the value 1 if the result of the comparison is true, or 0 otherwise.

The strict comparison operators all have one of the characters defining the operator doubled. The ==, \==, and ¬== operators test for an exact match between two strings. The two strings must be identical (character by character) and of the same length to be considered strictly equal. Similarly, the strict comparison operators such as >> or << carry out a simple character-by-character comparison, with no padding of either of the strings being compared. The comparison of the two strings is from left to right. If one string is shorter than the other and is a leading substring of another, then it is smaller than (less than) the other. The strict comparison operators also do not attempt to perform a numeric comparison on the two operands.

For all other comparison operators, if both terms involved are numeric, a numeric comparison (see Section 10.4, “Numeric Comparisons”) is effected. Otherwise, both terms are treated as character strings, leading and trailing whitespace characters are ignored, and the shorter string is padded with blanks on the right.

Character comparison and strict comparison operations are both case-sensitive, and the exact collating order might depend on the character set used for the implementation. In an ASCII environment, such as Windows and Unix-like systems, the ASCII character value of digits is lower than that of the alphabetic characters, and that of lowercase alphabetic characters is higher than that of uppercase alphabetic characters.

The comparison operators and operations are: