Shell Script to Multiply Two Numbers

Ever needed a quick way to multiply two numbers on your Linux or Unix system? A shell script can be a handy tool for this task.  In this post, we’ll create a shell script to Multiply Two Numbers

Method 1: Using Arithmetic Expansion (Bash)

This method is the most concise and modern way to perform arithmetic operations within the shell script itself.

#!/bin/bash

# Prompt the user for two numbers
read -p "Enter the first number: " num1
read -p "Enter the second number: " num2

# Perform multiplication using arithmetic expansion
product=$((num1 * num2))

# Display the result
echo "The product of $num1 and $num2 is: $product"

Explanation:

• #!/bin/bash specifies the interpreter for the script (Bash in this case).
• read commands prompt the user for input and store them in variables num1 and num2.
• (( )) performs arithmetic expansion. Here, num1 * num2 multiplies the two numbers and assigns the result to product.
• echo displays the final message with the calculated product.

Method 2: Using expr command

This method utilizes the expr command for performing calculations.

#!/bin/bash

# Prompt the user for two numbers
read -p "Enter the first number: " num1
read -p "Enter the second number: " num2

# Perform multiplication using expr
product=`expr $num1 \* $num2`  # Escape the asterisk for multiplication

# Display the result
echo "The product of $num1 and $num2 is: $product"

Explanation:

• Similar to the first method for prompting for input.
• expr command is used for arithmetic operations. Here, $num1 \* $num2 performs the multiplication with escaping the asterisk (*) to avoid conflicts with filename globbing.
• The result is stored in the product variable using backticks.
• echo displays the final message.

Saving and Running the Script

1. Save the script as a file with a .sh extension (e.g., multiply.sh).
2. Make the script executable using chmod +x multiply.sh.
3. Run the script from your terminal: ./multiply.sh.

These scripts provide a basic way to multiply two numbers using shell scripting. You can modify them further to accept arguments from the command line or perform more complex calculations.