code: public static String parse(String commandLine, final CommandLineParser.CallbackHandler handler, boolean strict,
              CommandContext ctx) throws CommandFormatException {
          if(commandLine == null) {
              return null;
          }
          SubstitutedLine sl = parseLine(commandLine, handler, strict, ctx);
          return sl == null ? null : sl.getSubstitued();
      }
docs: Returns the string which was actually parsed with all the substitutions performed