Find Factorial Of A Number in Bash Script

Q. Write a bash script to find the factorial of number?

What is a factorial number? A factorial number of any given number is the multiplication of all positive integers less than or equal to a given positive integer.

The factorial denoted with ! symbol. For example. The factorial of 5, 8 and 1 will be:

5! = 4 × 3 × 2 × 1 = 24
8! = 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5040
1! = 1

Example

A shell script to calculate the factorial of input number using for loop.

#!/bin/bash
# A shell script to find the factorial of a number

read -p "Enter a number" num
fact=1

for((i=2;i<=num;i++))
{
  fact=$((fact*i))
}

echo $fact

#!/bin/bash

# A shell script to find the factorial of a number

read -p "Enter a number" num

fact=1

for((i=2;i<=num;i++))

{

fact=$((fact*i))

}

echo $fact

Another Example

A shell script to calculate the factorial of input number using while loop.

#!/bin/bash
# A shell script to find the factorial of a number

read -p "Enter a number" num
fact=1

while [ $num -gt 1 ]
do
  fact=$((fact*num))
  num=$((num-1))
done

echo $fact

#!/bin/bash

# A shell script to find the factorial of a number

read -p "Enter a number" num

fact=1

while [ $num -gt 1 ]

fact=$((fact*num))

num=$((num-1))

done

echo $fact