请问，如果执行一个命令，IF ERRORLEVEL 后面的错误返回代号，是怎样定义的？？
比如：我想在GHOST恢复我的系统失败后，显示出错信息，而在恢复成功后，显示成功的信息，怎样设置？？
:RESTORE
CHOICE /C:YN /T:N,10 CAUTION:All data on disk C will be lost,are you sure
IF ERRORLEVEL 2 GOTO QUIT
LH SMARTDRV.EXE 4096
@echo Please waiting....
GHOST -clone,mode=pload,src=F:\WIN98BAK.GHO:1,dst=1:1 -sure
IF ERRORLEVEL ? ECHO Restore system failure! GOTO QUIT
@echo Your system is restored successfully.
@echo Please remove the floppy diskette and reboot your computer!
GOTO QUIT
比如：我想在GHOST恢复我的系统失败后，显示出错信息，而在恢复成功后，显示成功的信息，怎样设置？？
:RESTORE
CHOICE /C:YN /T:N,10 CAUTION:All data on disk C will be lost,are you sure
IF ERRORLEVEL 2 GOTO QUIT
LH SMARTDRV.EXE 4096
@echo Please waiting....
GHOST -clone,mode=pload,src=F:\WIN98BAK.GHO:1,dst=1:1 -sure
IF ERRORLEVEL ? ECHO Restore system failure! GOTO QUIT
@echo Your system is restored successfully.
@echo Please remove the floppy diskette and reboot your computer!
GOTO QUIT