Shell Script that accepts a positive integer and returns comma separated list of integers in descending order

Description: 

Write a  shell script that accepts exactly 1 argument which must be a positive integer. 

The script will print a comma-separated list of integers, all on the same line in descending order

Script: decreaseNum.sh

 

#!/bin/bash

#-----------------------------------------------

#user input

num=$1

temp=''

         

        #continue while input is greater than 0
 while [ $num -gt 0 ]
 do

                #append the numbers in decreasing order with comma-separated
  temp+="$num, "
  num=$(( $num - 1 ))
    done
 temp=$(echo $temp | sed 's/,$//')

 echo $temp

Output: