 |  |
4.4. Arithmetic Expressions
The Korn shell's let command performs arithmetic. ksh88 is restricted to integer arithmetic. ksh93 can do floating-point arithmetic as well. The Korn shell provides a way to substitute arithmetic 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; in decreasing order of precedence.
|
Operator | Description |
|---|---|
++ -- | Auto-increment and auto-decrement, both prefix and postfix. ksh93 only. |
+ |
|
- |
|
! ~ |
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. |
< > |
|
== != |
Equality; inequality (both evaluated left to right). |
& |
|
^ |
|
| |
|
&& |
|
|| |
|
?: |
Inline conditional evaluation. ksh93 only. |
*= /= %= = += -= <<= >>= &= ^= |= |
Assignment. |
, | Sequential expression evaluation. ksh93 only. |
4.4.2. Built-in Mathematical Functions (ksh93 only)
ksh93 provides access to the standard set of mathematical functions. They are called using C function call syntax.
| Name | Function | Name | Function |
|---|---|---|---|
| abs | Absolute value | log | Natural logarithm |
| acos | Arc cosine | sin | Sine |
| asin | Arc sine | sinh | Hyperbolic sine |
| cos | Cosine | sqrt | Square root |
| cosh | Hyperbolic cosine | tan | Tangent |
| exp | Exponential function | tanh | Hyperbolic tangent |
| int | Integer part of floating-point number |
4.4.3. 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
|  | |
| 4.3. Variables |  | 4.5. Command History |
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