code: public String getOptionValue(final char shortOption, final String defaultValue) {
          return (String) commandLine.getValue("-" + shortOption, defaultValue);
      }
docs: Returns the value of the specified option If the option is not present,
  returns the default value.
  
  @param shortOption
  The option short name
  @param defaultValue
  The default value
  
  @return The option value or, if not specified, the default value * @see it.jnrpe.ICommandLine#getOptionValue(char, String)