The ISWINDOW command

Use the return code of the DOS command ISWINDOW to distinguish between windowed and fullscreen DOS session (0 = fullscreen, 1 = window).
Example:

 
  @ECHO OFF
  REM *** sample DOS batch to distinguish
  REM     between window and fullscreen

  REM --- call the util program
  iswindow
  if errorlevel 1 goto IsWin

:IsFS
  SET sessionType=FS
  ECHO. Running in a DOS Fullscreen session
  GOTO NEXT

:IsWin
  SET sessionType=WIN
  ECHO. Running in a DOS window session
:NEXT