Additional information available:

WINDOW

   Shrinks the current window.

   Format

     SHRINK WINDOW  line-count

Additional information available:

Parameter

line-count
   Indicates the number of screen lines you want to subtract from the
   current window. The maximum size of a window depends on the size
   and type of the terminal screen you are using. The minimum size is
   one line of text and one line for the status line.