title: I am getting expr syntax errors in bash shell for a simple program
body: <pre><code>#!/bin/bash
  clear 
  echo "Enter a number"
  read a 
  s = 0
  while [ $a -gt 0 ]
  do
  r = ` expr $a % 10 `
  s = ` expr $s + $r `
  a = ` expr $a / 10 `
  done
  echo "sum of digits is = $s"
  </code></pre>
  
  <p>This is my code guys .
  I am getting a bunch of expr syntax errors.
  I am using the bash shell.
  Thanks!</p>