Invokes the VMS Debugger after program execution  is  interrupted by
  CTRL/Y, but only if the /NOTRACEBACK  qualifier  was  not  specified
  with the LINK command  when  the program was linked.  For a complete
  description  of  the VMS Debugger, including more information  about
  the DEBUG command, see the VMS Debugger Manual.

  Format:

    DEBUG

Additional information available:

Examples

  1.   $ FORTRAN/DEBUG/NOOPTIMIZE   WIDGET
       $ LINK/DEBUG  WIDGET
       $ RUN WIDGET

          VAX DEBUG Version V5.0-00

       %DEBUG-I-INITIAL, language is FORTRAN, module set to 'WIDGET'
       DBG> GO
       ENTER NAME:
       ENTER NAME:
       ENTER NAME:
       ^Y
       $ DEBUG
       DBG>

  The FORTRAN and LINK commands both specify the /DEBUG  qualifier  to
  compile   the   program   WIDGET.FOR   with  debugger  symbol  table
  information and to include the debugger in the image file.  The  RUN
  command  begins  execution  of  the  image  WIDGET.EXE,  which loops
  uncontrollably.   CTRL/Y  interrupts  the  program,  and  the  DEBUG
  command gives control to the debugger.