code: public String getValue(String key) {
          if (key.indexOf(DOLLAR) == -1) {
              String value = getVariable(key);
  
              if (value == null)
                  return null;
  
              if (value.indexOf(DOLLAR) == -1)
                  return value;
              else
                  return parseValue(value);
          }
          return parseValue(key);
      }
docs: line that contains a non escaped $
  
  @param key input
  @return line with variables replaced with their value