How to check if a variable exists in a batch file?

Question

I am using the call command:

call beingcalled.bat randomnumber 

In beingcalled.bat:

@echo off set call=%1 echo %call% set call=%call%%call% call caller.bat %call%` 

In caller.bat:

@echo off set calltwo=%1 echo %calltwo% if "%calltwo%"== "" (     echo Error ) else (     call beingcalled.bat randomnumber ) 

Why does the command if "%calltwo%"== "" not work? And how do I see if a variable was set?

Answer 1

IF "%Variable%"=="" ECHO Variable is NOT defined 

This should help but this works, provided the value of Variable does not contain double quotes. Or you may try. Both worked for me.

VERIFY OTHER 2>nul SETLOCAL ENABLEEXTENSIONS IF ERRORLEVEL 1 ECHO Unable to enable extensions IF DEFINED MyVar (ECHO MyVar IS defined) ELSE (ECHO MyVar is NOT defined) ENDLOCAL 

source http://www.robvanderwoude.com/battech_defined.php