Bash 脚本 – 算术运算符

在本文中，我们将看到 bash 脚本中的算术运算符。算术运算符用于执行算术运算。

Bash 脚本支持 11 个算术运算运算符。下面给出了所有运算符及其用途：

Operator	Name	Use	Example
+	Addition	It adds two operands	result= a+b
–	Subtraction	It subtract second operand from first one	result= a-b
*	Multiplication	Multiply two operands	result= a*b
/	Division	Return the quotient after diving first operand from second operands	16/3 result = 5
%	Modulo	Return remainder after dividing first operand from second operand	16/ 3 result = 1
+=	Increment by constant	Increment value of first operand with given constant value	x= 13 x+=3 result = 16
-=	Decrement by constant	Decrement value of first operand with given constant value	x= 13 x -= 3 result = 10
*=	Multiply by constant	Multiply the given operand with the constant value	x= 10 x*=3 result = 30
/=	Divide by constant	Divide the operand with given constant value and return the quotient	x = 31 x/=3 result = 10
%=	Remainder by dividing with constant	Divide the operand with given constant value and return the remainder	x= 31 x%=3 result = 1
**	Exponentiation	The result is second operand raised to the power of first operand.	3**2 result = 9

让我们看看算术运算运算符的使用示例：

添加

代码：

Sum=$((10+3))  
echo "Sum = $Sum"

输出：

减法

代码：

Difference=$((10-3))  
echo "Difference = $Difference"

输出：

乘法

代码：

Product=$((10*3))  
echo "Product = $Product"

输出：

分配

代码：

Division=$((10/3))  
echo "Division = $Division"

输出：

模数

代码：

Modulo=$((10%3))  
echo "Modulo = $Modulo"

输出：

求幂

代码：

Exponent=$((10**2))  
echo "Exponent = $Exponent"

输出：

显示在单个代码中使用所有运算符的示例

代码：

x=10
y=20
echo "x=10, y=5"  
echo "Addition of x and y"  
echo $(( $x + $y ))  
echo "Subtraction of x and y"  
echo $(( $x - $y ))  
echo "Multiplication of x and y"  
echo $(( $x * $y ))  
echo "Division of x by y"  
echo $(( $x / $y ))  
echo "Exponentiation of x,y"  
echo $(( $x ** $y ))  
echo "Modular Division of x,y"  
echo $(( $x % $y ))  
echo "Incrementing x by 10, then x= "  
(( x += 10 ))    
echo $x  
echo "Decrementing x by 15, then x= "  
(( x -= 15 ))  
echo $x  
echo "Multiply of x by 2, then x="  
(( x *= 2 ))  
echo $x  
echo "Dividing x by 5, x= "  
(( x /= 5 ))  
echo $x  
echo "Remainder of Dividing x by 5, x="  
(( x %= 5 ))  
echo $x

输出：

在 Bash 中计算算术运算的不同方法

有一些不同的方法来执行算术运算。

1.双括号

这可以用于算术扩展。让我们看一个例子来看看双引号的使用。

代码：

#!/bin/bash
 
first=10
second=3
 
echo $(( first + second ))   # addition
echo $(( $first + $second )) # this is also valid
 
echo $(( first - second ))   # subtraction
echo $(( $first - $second )) # this is also valid

输出：

2.使用let命令

let 命令用于执行算术运算。

例子

代码：

#!/bin/bash
 
x=10
y=3
 
let "z = $(( x * y ))"  # multiplication
echo $z
let z=$((x*y))
echo $z
 
let "z = $(( x / y ))"  # division
echo $z
let z=$((x/y))
echo $z

输出：

3. 带反引号的 expr 命令

算术扩展可以使用反引号和 expr 来完成。

代码：

a=10
b=3

# there must be spaces before/after the operator

sum=`expr $a + $b`
echo $sum

sub=`expr $a - $b`
echo $sub

mul=`expr $a \* $b`
echo $mul

div=`expr $a / $b`
echo $div

输出：