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:
| $((  | Use the value of the enclosed arithmetic expression. | 
| 
 | Interpret integer  | 
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. | 
| = += -= | |
| <<= >>= | |
| &= ^= |= | 
See the let command for more information and examples.
let "count=0" "i = i + 1" Assigniandcount. let "num % 2" Test for an even number. (( percent >= 0 && percent <= 100 )) Test the range of a value.