Check if process returns 0 with batch file

ERRORLEVEL will contain the return code of the last command. Sadly you can only check >= for it.

Note specifically this line in the MSDN documentation for the If statement:

errorlevel Number

Specifies a true
condition only if the previous program
run by Cmd.exe returned an exit code
equal to or greater than Number.

So to check for 0 you need to think outside the box:

IF ERRORLEVEL 1 GOTO errorHandling
REM no error here, errolevel == 0
:errorHandling

Or if you want to code error handling first:

IF NOT ERRORLEVEL 1 GOTO no_error
REM errorhandling, errorlevel >= 1
:no_error

Further information about BAT programming: http://www.ericphelps.com/batch/
Or more specific for Windows cmd: MSDN using batch files