WINAPI: GetUserNameA         ADVAPI32.DLL
WINAPI: WinExec              KERNEL32.DLL

VARIABLE BufferSize  256 BufferSize !

: GU
  BufferSize HERE GetUserNameA 0= IF 5 HALT THEN
  HERE ASCIIZ> DUP ALLOT
  BL WORD COUNT COMPARE 0<> IF 4 HALT THEN
  1 1 PARSE OVER + 0! WinExec BYE
;
FALSE TO ?GUI
' GU TO <PRE> S" GU.EXE" SAVE BYE