MPE/iX Shell and Utilities Reference Manual, Vol 1

awk(1) MPE/iX Shell and Utilities awk(1)

Symbol Table

You can access the symbol table through the built-in array SYMTAB.

SYMTAB[expr]

is equivalent to the variable named by the evaluation of expr. For example,

SYMTAB["var"]

is a synonym for the variable var.

Environment

An awk program can determine its initial environment by examining the ENVIRON array. If

the environment consists of entries of the form:

name=value

then

ENVIRON[name]

has string value

"value"

For example, the following program is equivalent to the default output of env(1):

BEGIN {

for (i in ENVIRON)

printf("%s=%s\n", i, ENVIRON[i])

exit

}

Operators

awk follows the usual precedence order of arithmetic operations, unless overridden with

parentheses; a table giving the order of operations appears later in this section.

The unary operators are +, -, ++, and --, where you can use the ++ and -- operators as

either postﬁx or preﬁx operators, as in

C. The binary arithmetic operators are +, -, *, /, %, and

ˆ.

The conditional operator

expr ? expr1 : expr2

evaluates to the expr1 if the value of expr is non-zero, and to expr2 otherwise.

Commands and Utilities 1-21