Bash Script to Divide Two Numbers with Output

Use Bash arithmetic expansion with result=$((num1 / num2)) to divide two numbers, ensuring num2 is not zero to avoid errors.

Examples

Inputnum1=10, num2=2

OutputResult: 5

Inputnum1=15, num2=4

OutputResult: 3

Inputnum1=7, num2=0

OutputError: Division by zero is not allowed.

How to Think About It

To divide two numbers in Bash, first get the two numbers as input. Then check if the divisor is zero to avoid errors. If not zero, use Bash's arithmetic expansion with $(( )) to perform integer division and print the result.

Algorithm

1

Get the first number as input.

2

Get the second number as input.

3

Check if the second number is zero.

4

If zero, print an error message and stop.

5

Otherwise, divide the first number by the second using arithmetic expansion.

6

Print the division result.

Code

bash

#!/bin/bash

read -p "Enter first number: " num1
read -p "Enter second number: " num2

if [ "$num2" -eq 0 ]; then
  echo "Error: Division by zero is not allowed."
  exit 1
fi

result=$((num1 / num2))
echo "Result: $result"

Output

Enter first number: 10
Enter second number: 2
Result: 5

Dry Run

Let's trace dividing 10 by 2 through the code

1

Input numbers

num1=10, num2=2

2

Check divisor

num2 is 2, not zero, continue

3

Calculate division

result = 10 / 2 = 5

Step	Variable	Value
1	num1	10
1	num2	2
3	result	5

Why This Works

Step 1: Input reading

The script uses read to get two numbers from the user.

Step 2: Division by zero check

It checks if the divisor is zero with [ "$num2" -eq 0 ] to prevent errors.

Step 3: Perform division

The division uses Bash arithmetic expansion $((num1 / num2)) which does integer division.

Step 4: Output result

Finally, it prints the result with echo.

Alternative Approaches

Using bc for floating point division

bash

#!/bin/bash

read -p "Enter first number: " num1
read -p "Enter second number: " num2

if [ "$num2" = "0" ]; then
  echo "Error: Division by zero is not allowed."
  exit 1
fi

result=$(echo "scale=2; $num1 / $num2" | bc)
echo "Result: $result"

This method allows decimal division but requires the bc utility.

Using awk for division

bash

#!/bin/bash

read -p "Enter first number: " num1
read -p "Enter second number: " num2

if [ "$num2" = "0" ]; then
  echo "Error: Division by zero is not allowed."
  exit 1
fi

result=$(awk "BEGIN {print $num1/$num2}")
echo "Result: $result"

This method also supports floating point division using awk.

Complexity: O(1) time, O(1) space

Time Complexity

The division operation and checks run in constant time since they involve only simple arithmetic and comparisons.

Space Complexity

The script uses a fixed amount of memory for variables, so space complexity is constant.

Which Approach is Fastest?

Using Bash arithmetic expansion is fastest for integer division; using bc or awk adds overhead but supports decimals.

Approach	Time	Space	Best For
Bash arithmetic expansion	O(1)	O(1)	Fast integer division
bc utility	O(1)	O(1)	Floating point division with decimals
awk utility	O(1)	O(1)	Floating point division with decimals