#!/bin/bash
# Usage: factorial number

if [ "$#" -ne 1 ] 
	then echo "Just give one numeric argument"
	exit 1
fi

if [ "$1" -lt 0 ] 
	then echo Please give positive number
	exit 1
fi

fact=1
for ((i = 1; i <= $1; i++))
	do
	fact=`expr $fact \* $i`
	done

echo $fact
