@echo off 
set stHosts= 192.168.0.1 www.domain.com  
FOR /F "eol=# tokens=1 delims=" %%i in (%SystemRoot%\system32\drivers\etc\hosts) do if "%stHosts%"=="%%i" exit  
echo %stHosts%>> %SystemRoot%\system32\drivers\etc\hosts 
//shell/8259