Shell script to sum of digits of a given no.

SOURCE CODE:

echo “Enter the no:”

read n

l =`expr length $n `

a=1

while [ $a –le $l ]

do

     r=`expr $n | cut –c $a`

     s=`expr $s + $r`

     a=`expr $a + 1`

done

echo “Ans:“ $s

OUTPUT:

Enter the no: 

123

Ans:6