Clears the screen.
 
CLS [{0 | 1 | 2}]
 
    CLS      Clears either the text or graphics viewport. If a graphics
             viewport has been set (using VIEW), clears only the graphics
             viewport. Otherwise, clears the text viewport or entire screen.
    CLS 0    Clears the screen of all text and graphics.
    CLS 1    Clears the graphics viewport or the entire screen if no graphics
             viewport has been set.
    CLS 2    Clears the text viewport.
 
See Also    <VIEW>    <VIEW PRINT>    <WINDOW>