CLS Command Details
 
Syntax
   CLS [{0|1|2}]
 
  Statement  Description
  CLS 0      Clears the screen of all text and graphics.
  CLS 1      Clears only the graphics viewport if a VIEW statement
             has been executed. Otherwise, CLS 1 clears the entire
             screen.
  CLS 2      Clears only the text viewport, leaving the bottom screen
             line (line 25, 30, 43, or 60 depending on the screen
             mode) unchanged.
  CLS        Clears either the graphics viewport or the text
             viewport. If the graphics viewport is active, then CLS
             with no argument clears only the viewport. If the
             graphics viewport is inactive, then CLS clears the text
             viewport and refreshes the function key display line
             (the bottom screen line).
 
The CLS statement also returns the cursor to the home position
in the top left corner of the screen.