The .FLAGS CONTROL and .NO FLAGS CONTROL commands control
    recognition of the Control flag character (the period (.) that
    begins a DSR command). You can enter .FLAGS CONTROL to change
    the character that precedes the commands from a period (.) to a
    character of your choice. You can enter .NO FLAGS CONTROL to turn
    off recognition of the Control flag character.

                                   NOTE

       There is no way to reenable recognition of the Control flag
       once you enter the .NO FLAGS CONTROL command.

    Formats

      .FLAGS CONTROL  [k]

      .NO FLAGS CONTROL

    Abreviated formats

      .FL CONTROL  [k]

      .NFL CONTROL