Delete a part of the parameter

 
/* delete the parameter "/L:filename" if it exists                    */

  parse arg part1 "/L:" logFile " " part2
  ProgParm = part1 part2
  drop part1 part2
                        /* Use the following command to further parse */
                        /* the parameters                             */
  parse var progParm parm1 parm2 parm3