Equality Operators
The equality operators listed in Table 3-6 are much like the relational operators.
Table 3.6. Equality Operators
| Numeric | String | Meaning | 
|---|---|---|
| == | eq | Equal to | 
| != | ne | Not equal to | 
| <=> | cmp | Comparison, with signed result | 
The equal and not-equal operators return for true and "" for false (just as the relational operators do). The <=> and cmp operators return -1 if the left operand is less than the right operand, if they are equal, and +1 if the left operand is greater than the right. Although the equality operators appear to be similar to the relational operators, they do have a lower precedence level, so $a < $b <=> $c < $d is syntactically valid.
 For reasons that are apparent to anyone who has seen Star Wars, the <=> operator is known as the "spaceship" operator.