How do you find the factorial of a number in a Bash script?

Question

In shell scripting how to find factorial of a number?

Answer 1

#!/bin/bash
counter=$1 #first argument
factorial=1
while [ $counter -gt 0 ] #while counter > 0
do
   factorial=$(( $factorial * $counter ))
   counter=$(( $counter - 1 ))
done
echo $factorial