FUNDAMENTALS A Complete Guide for Beginners

To multiply variable in Bash, you can follow these steps:

- Firstly,
**initialize**two variables. - After that, multiply the two variables using the
*****operator with**$(..)**or the**let command**, or the**expr command**. - Don’t forget to assign the above multiplication to a variable.
- Print the final variable with the
**echo command**.

In this article, I will discuss the steps to multiply the bash variable in detail. Keep reading.

## Basic Syntax to Multiply Bash Variable

You can multiply two variables using **arithmetic expansion $(..)**, **let command**, or **expr command**. The syntax of these approaches is given below:

- Using
**Arithmetic Expansion**

`result = variable1 * variable2`

- Using the
**let Command**

`let “result = variable1 * variable2”`

- Using the
**expr Command**

`result=`expr $variable1 \* $variable2``

## 6+ Practical Examples Related to Multiply Variable in Bash

Multiplying Bash variable is one helpful tool for **data processing**. In this section, I will show some examples related to multiplying Bash variables utilizing the **let command**, **expr command**, **arithmetic expansion, bc command**, and **for loop**. After going through these examples, you will be skillful enough to multiply bash variables whenever necessary.

### 1. Multiply Two Variables with “*” Operator and “$(())” in Bash

To multiply the variable in bash, you can use the “*” operator and “$(())”. Here I have two variables. Now I will incorporate **arithmetic expansion** to calculate the multiplication of these two variables and print the result on the terminal. Check out the bash script:

```
#!/bin/bash
#assigning num1 and num2 variable
num1=50
num2=10
#calculating the multiplication of the two variables num1 and num2
result=$((num1 * num2))
#printing the multiplication result on the terminal
echo "Multiplication of $num1 and $num2 is:$result"
```

Here, the **num1=50 **and** num2=10** commands have assigned a value to the **num1** and the **num2** variables. Subsequently, the `result=$((num1 * num2))`

command has calculated the multiplication of the **num1** and the **num2** variables and keeps the result on the result variable. Then the **echo **“Multiplication of $num1 and $num2 is:$result” command has printed the result on the terminal.

The image shows the bash script has multiplicated the **num1** and the **num2** variables and printed the result on the terminal.

### 2. Multiply Two Variables Using the “expr” Command in Bash

To multiply a variable in bash. you can use the `expr`

command. In this example, I will use two variables & perform multiplication on them. For that, I will incorporate the **expr command** to calculate the multiplication of these two variables and print the result on the terminal. To know more, follow the below script:

```
#/bin/bash
#assigning num1 and num2 variable
num1=50
num2=10
#calculating the multiplication of the two variables num1 and num2
result=`expr $num1 \* $num2`
#printing the multiplication result on the terminal
echo "Multiplication of $num1 and $num2 is:$result"
```

The **num1=50 num2=10** commands have assigned a value to the **num1** and **num2** variables. Subsequently, the `result=`expr $num1 \* $num2``

command has calculated the multiplication of the **num1** and the **num2** variables and keeps the result on the result variable. Then the **echo **“Multiplication of $num1 and $num2 is:$result” command has printed the result on the terminal.

The image shows the bash script has multiplicated the **num1** and the **num2** variables utilizing the **expr command** and printed the result on the terminal.

### 3. Multiply Bash Variables Using “$((..))” Expansion

Here to multiply bash variables, I will develop a Bash script that will contain a `for loop`

which will iterate from** 1** to **11** of the **val variable,** and a calculation of **multiplication and addition** will be done for each value of the **val variable** utilizing the **arithmetic expansion**. To accomplish this task, check the below script:

```
#!/bin/bash
#for loop iterate the value of i from 1 to 11
for (( num =1; num <12; ++num )); do
#does the calculation for each value of i from 1 to 11
result=$(( 2*num + 1 ))
#prints each value of result
echo "$result"
done
```

The `for (( num = 1; val <12; ++num )); do`

command has initiated a for loop which iterates the value of val from 0 till 11. The `result=$(( 2*num + 1 ))`

command has multiplied each value of the val variable and added 1 utilizing the **arithmetic expansion** and finally, the **echo **“$result” command has printed the result for each value of the **num** variable on the terminal.

The image shows that the Bash script has calculated the multiplication and addition utilizing **for loop** and **arithmetic expansion** and printed the result on the terminal.

### 4. Multiply Variable in Bash Using the “let” Command

Here I will develop a Bash script that will contain a **for loop** which will iterate from** 0 **to some value of the **val** variable and a calculation of **multiplication and addition** will be done for each value of the **val** variable utilizing the **let command**. Follow the below script:

```
#!/bin/bash
#for loop iterate the value of val from 0 to 12
for (( val = 0; val <13; ++val )); do
#does the calculation for each value of val from 1 to 11
let answer="9*val+2"
#prints each value of the answer
echo "$answer"
done
```

The `for (( val = 0; val <13; ++val )); do`

command has initiated a for loop which iterates the value of val from 0 till 12. The `let answer="9*val+2"`

command has multiplied each value of the val variable and added 2 utilizing the **let command** and finally, the **echo **“$answer” command has printed the result for each value of the **val** variable on the terminal.

The image shows that the Bash script has calculated the multiplication and addition utilizing **for loop** and **let command** and printed result on the terminal.

### 5. Multiply an Assigned Variable With a Number in Bash

To multiply an assigned variable with a number, check this example. Here, I have a variable named **num1**. I will multiply **10** with this variable** num1**. To accomplish this, write the below script:

```
#!/bin/bash
#assigning num1 variable
num1=50
#calculating the multiplication of the variables num1 and 10
result=$((num1 * 10))
#printing the multiplication result on the terminal
echo "Multiplication of $num1 and 10 is:$result"
```

The **num1=50** command has assigned a value to the **num1** variable. Then the `result=$((num1 * 10))`

command has multiplied 10 with the **num1** variable. Finally, the **echo **“Multiplication of $num1 and 10 is:$result” command has printed the result on the terminal.

The bash script has multiplied **10 **with the** num1 variable** and printed the **result (500)** on the terminal.

### 6. Multiply Two Float Numbers With the “bc” Command

To multiply float numbers in bash, you can use the `bc`

command. In this example, I have two float variables named **float_var1** and **float_var2**. They contain float numbers into them. Now I will multiply the variable **float_var1** and the variable **float_var2** utilizing the **bc command** and print the result on the terminal. Here’s the bash script:

```
#!/bin/bash
# Define two float variables
float_var1=3.14
float_var2=2.5
# Use bc to multiply the float variables
result=$(echo "$float_var1 * $float_var2" | bc)
# Print the result
echo "The result of multiplying $float_var1 and $float_var2 is: $result"
```

The **float_var1=3.14 float_var2=2.5** commands have defined the two variables. After that, the `result=$(echo "$float_var1 * $float_var2" | bc)`

command calculated the multiplication of the variable **float_var1** and the variable **float_var2** utilizing the bc command and kept it on the result variable. Finally, the **echo **“The result of multiplying $float_var1 and $float_var2 is: $result” command has printed the result on the terminal.

The bash script has multiplied **two float numbers** utilizing the **bc command** and printed them on the terminal.

### Bonus Example: Division of Numbers in Bash Using the “expr” Command

To perform division operations in bash, check this example thoroughly. In this example, I have two variables named **A** and **B**. Now I will divide the variable **A** by variable **B** and print the result on the terminal. Here’s the bash script for this:

```
#!/bin/bash
#assigning A and B variable
A=25
B=5
#Division using the expr command then printing the result
echo "A / B = `expr $A / $B`"
```

The **A=25 B=5** command has assigned value to the **A** and the **B** variables. Then the `echo "A / B = `expr $A / $B`"`

command divides variable A by variable B with the help of the expr command and prints the result with the help of the **echo command.**

The image shows that the Bash script has divided **variable A** by **variable B** and printed the result on the terminal.

## Conclusion

Here, I have tried to give you a concise idea of how to **multiply the bash variable**. I believe after going through this article, you will be competent enough to do multiplication of bash variables wherever necessary.

## People Also Ask

### How to multiply two variables in Bash?

To multiply two variables **number1** and **number2** in Bash, you can use this syntax: `multiplication=$((number1 * number2))`

.

### Can I multiply a variable with a constant?

Yes, you can easily multiply a variable with a constant using the following syntax:

`result=$((num1 * [value of constant]))`

### How to combine variables in bash?

To combine variables in bash, you can follow this script:

```
X="String"
Y="Concatenation!"
echo "${X}${Y}"
```

This script will print “String Concatenation!” On the terminal.

### What represents multiplication?

Multiplication is represented by an **asterisk (*)** and is used in computer languages. Cross(x) is used for writing on the notebook.

### Can I multiply random variables?

Yes, you can multiply random variables by using **arithmetic expansion**, **let**, and **expr** commands.

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