Проверка занятости порта в Windows из bat-файла

@echo off
rem Copyright (c) 2009 Igor Nikolaev

if "%1" == "" goto portNotSpecified

netstat -an | findstr /R "^[^a-zA-Z]*[a-zA-Z]*[^:]*:%1[^0-9][^a-zA-Z]*LISTENING$"

if %errorlevel% == 0 goto portIsUsed
goto portIsNotUsed

:portNotSpecified
echo Usage: checkport port
goto exit

:portIsUsed
echo Port %1 is used
goto exit

:portIsNotUsed
echo Port %1 is not used
goto exit

:exit
exit %errorlevel%