assignment

= +=

a += 2

a = a + 2

logical OR

||

a || b

1 if a or b is true, 0 otherwise

logical AND

&&

a && b

1 if a and b are true, 0 otherwise

array membership

in

j in a

1 if a[j] exists, 0 otherwise

string matching

~ !~

$1 ~ /go/

match if the 1st field contains go

relational

< <= == != >= >

a == b

1 if a is equal to b, 0 otherwise

concatenation

"x" + "z"

"xz"

add, subtract

+ -

a + b

sum of a and b

multiply, divide

* /

a * b

product of a and b

 

field

$

$n+1

value of the nth field plus 1

grouping

( )

(AB) + C

matches ABC, ABABC, ...