@echo off

if "%b2eprogramfilename%"==""  (

	echo To see any results you need to convert this file into an exe
	pause
	goto :eof

)

%extd% /messagebox "Left" "This example will extract a string with a length of 3 characters from the left of 'String'"
%extd% /left "String" 3
if "%result%"=="" (exit) else (set string="%result%")
%extd% /messagebox Result %string%