#  Chapter 4The Bourne Shell and Korn Shell ## 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

```let "count=0" "i = i + 1"	Assign` i` and` count`.   4.3 Variables 4.5 Command History 