title: Multiplication with expr in shell script
body: <p>I am making a basic calculator to add, subtract, multiply, and divide. </p>
  
  <p>Addition works, but not multiplication. When I attempt to multiply, I get the "You did not run the program correctly" response:</p>
  
  <pre><code>$ ./calculator 4 + 5
  9
  $ ./calculator 4 * 5
  You did not run the program correctly
  Example: calculator 4 + 5
  </code></pre>
  
  <p>I've searched around on google, where I found the <code>\\*</code> code, but still doesn't work. Can someone provide me with a solution or explanation?</p>
  
  <p>Here is my code</p>
  
  <pre><code>#!/bin/bash
  
  if [ $# != 3 ]; then  
    echo You did not run the program correctly   
    echo Example: calculator 4 + 5                
    exit 1 
  fi
  
  if [ $2 = "+" ]; then    
    ANSWER=`expr $1 + $3`    
   echo $ANSWER 
  fi
  
  if [ $2 = "*" ]; then
    ANSWER=`expr $1 \\* $3`  
    echo $ANSWER 
  fi
  
  exit 0
  </code></pre>