
\Sexpr\S:  Examples

        a=`expr $a + 1`

   Evaluates the expression "$a + 1" and adds 1 to the value of variable "a".

   ---------------------------------------------------------------------------

        expr $a : ".*"

   Evaluates the expression "$a : ".*"".  The operator ":" is the matching
   operator.  It checks the number of characters in the second argument that
   match the first argument.  Here it is matching the regular expression ".*"
   and the value of the variable "a".  ".*" matches any character, therefore
   \Sexpr\S returns the number of characters in the value of "a".
