Synopsis:
   $winsize([<window>])

Technical:
   This returns the height, in lines, of the specified window, not including
   the status line or the input line.  It may be given either a window name
   or a window number.  If no window is specified, the current is assumed.

Practical:
   This function is mainly useful for aliased commands that generate a lot
   of output.  Since the height of the window is known, the script can page
   the output a window at a time.

Returns:
   number of lines in window, or nothing if window does not exist

Examples:
   $winsize(1)                 returns size of window #1
   $winsize(main)              returns size of window "main"
   $winsize()                  returns size of current window

See Also:
   geom(6); window(4) size

