------------------ Table 4.4 ------------------
 awk Operators (increasing order of precedence)

= += -k *= /= %=        assignment; v op= expr is v = v op (expr)
||                      OR: expr1 || expr2 true if either is;
                            expr2 not evaluated if expr1 is true
&&                      AND: expr1 && expr2 true if both are;
                            expr2 not evaluated if expr1 is false
!                       negate value of expression
> >= < <= == != ~ !~    relational operators;
                            ~ and !~ are match and non-match
nothing                 string concatenation
+ -                     plus, minus
* / %                   multiply, divide, remainder
++ --                   increment, decrement (prefix or postfix)