#!/bin/bash
function fak()
{
if [ $# -eq 1  ]
 then
  MUL=1
 else
  MUL=$2
 fi
  COUNT=$1
if [ "$COUNT" -eq 1 ] 
then
  echo $MUL
else 
MUL=$(($COUNT*$MUL))
COUNT=$(($COUNT-1))
fak $COUNT $MUL
fi      
}
fak $1