My workspace echoes code entered as opposed to actually executing when run from comm line. How do I stop this?

<? php //number in pounds we want to convert to kg $pounds = 140; //floating point value for lb to kg conversion $lb_to_kg = 0.453592; //use above variables to calc pounds * kg conversion $kilograms = $pounds * $lb_to_kg; //display lb to kg echo "Weight"; echo $pounds; echo " lb = "; echo $kilograms; echo "kg";

//number in miles we want to convert to km $miles = 2.5; //floating point value for mile to km conversion $mile_to_km = 1.60934; //use above variables to calc miles * km coversion $kilometers = $miles * $mile_to_km; //display miles to km echo "Distance: "; echo $miles; echo " miles = " echo $kilometers"; echo " km";

?>

When this code is run using the command 'php units.php', it prints all of this text rather than executing and returning the calculated sum.