[Chapter 4] 4.4 Arithmetic Expressions

4.4 Arithmetic Expressions

The Korn shell's let command performs integer arithmetic. The Korn shell provides a way to substitute integer values (for use as command arguments or in variables); base conversion is also possible:

$(( `expr` ))	Use the value of the enclosed arithmetic expression.
`B` #`n`	Interpret integer `n` in numeric base `B` . For example, 8#100 specifies the octal equivalent of decimal 64.

4.4.1 Operators

The Korn shell uses arithmetic operators from the C programming language; they are listed below in decreasing order of precedence:

-	Unary minus.
! ~	Logical negation; binary inversion (one's complement).
* / %	Multiplication; division; modulus (remainder).
+ -	Addition; subtraction.
<< >>	Bitwise left shift; bitwise right shift.
<= >=	Less than or equal to; greater than or equal to.
< >	Less than; greater than.
== !=	Equality; inequality (both evaluated left to right).
&	Bitwise AND.
^	Bitwise exclusive OR.
\|	Bitwise OR.
&&	Logical AND.
\|\|	Logical OR.
*= /= %=	Assignment.
= += -=
<<= >>=
&= ^= \|=

4.4.2 Examples

See the let command for more information and examples.

let "count=0" "i = i + 1"	
Assign

 i
 and
 count
.
let "num % 2"	
Test for an even number.

(( percent >= 0 && percent <= 100 ))	
Test the range of a value.