The following commands are used to control screen mode and screen
    displays:

    SET MODE [NO]SCREEN    Enables/disables screen mode
    DISPLAY                Creates or modifies a display
    SCROLL                 Scrolls a display
    EXPAND                 Expands or contracts a display
    MOVE                   Moves a display across the screen
    (SHOW,CANCEL) DISPLAY  (Identifies, deletes) a display
    (SET,SHOW,CANCEL)      (Creates, identifies, deletes) a window
    WINDOW                 definition
    SELECT                 Selects a display for a display attribute
    SHOW SELECT            Identifies the displays selected for each
                           of the display attributes
    SAVE                   Saves the current contents of a display
                           into another display
    EXTRACT                Saves a display or the current screen
                           state into a file
    (SET,SHOW) TERMINAL    (Establishes, displays) the terminal
                           screen height and width that the debugger
                           uses when it formats displays and other
                           output
    SET MODE [NO]SCROLL    Controls whether an output display is
                           updated line by line or once per command
    Ctrl/W                 Refreshes the screen
    DISPLAY/REFRESH