# Linux Shell Script Tutorial
# Script to reverse given no
#
# Algo:
#       1) Input number n
#       2) Set rev=0, sd=0
#   	3) Find single digit in sd as n % 10 it will give (left most digit)
#       4) Construct revrse no as rev * 10 + sd
#       5) Decrment n by 1
#       6) Is n is greater than zero, if yes goto step 3, otherwise next step
#       7) Print rev
#
if [ $# -ne 1 ]
then
    echo "Usage: $0   number"
    echo "       I will find reverse of given number"
    echo "       For eg. $0 123, I will print 321"
    exit 1
fi

n=$1
rev=0
sd=0

while [ $n -gt 0 ]
do
    sd=`expr $n % 10`
    rev=`expr $rev \* 10  + $sd`
    n=`expr $n / 10`
done
    echo  "Reverse number is $rev"