code: public void removeCharCommand()
      {
          if (!isCharCommand())
              return;
          if (getValue() == null)
              return;
          if (getValue().length() < 2)
              return;
          if (getValue().length() == 2)
          {
              setValue(null);
              setUsed(true);
              return;
          }
          setValue("-" + getValue().substring(2));
      }
docs: <p>
  removeCharCommand.
  </p>