I'm trying to write a build script that will: 1. Minify JS and CSS files 2. Read them into variables 3. Insert those strings into HTML The first 2 steps are successful, but I am unable to successfully insert the strings. I've found that if I just try to insert a string with no spaces or special characters, it will work. But once I try to insert the JS or CSS strings, it seems they are being expanded during the call and then parsed. Here is my code: SETLOCAL EnableDelayedExpansion :: Minify JS java -jar yuicompressor-2.4.2.jar --type js --nomunge "%~dp0src\main.js" > temp1.txt SET /p MAINJS= < temp1.txt :: Minify CSS java -jar yuicompressor-2.4.2.jar --type css "%~dp0src\main.css" > temp3.txt SET /p MAINCSS= < temp3.txt :: Insert Strings BatchSubstitute.bat ^<!--MAINCSS--^> "%MAINCSS%" "%~dp0src\main.html" > temp.txt ENDLOCAL Here is the BatchSubstitute.bat code: (from http://www.dostips.com/DtCodeBatchFiles.php#Batch.FindAndReplace) @echo off REM -- Prepare the Command Processor -- SETLOCAL ENABLEEXTENSIONS SETLOCAL DISABLEDELAYEDEXPANSION ::BatchSubstitude - parses a File line by line and replaces a substring" ::syntax: BatchSubstitude.bat OldStr NewStr File :: OldStr [in] - string to be replaced :: NewStr [in] - string to replace with :: File [in] - file to be parsed if "%*"=="" findstr "^::" "%~f0"&GOTO:EOF for /f "tokens=1,* delims=]" %%A in ('"type %3|find /n /v """') do ( set "line=%%B" if defined line ( call set "line=echo.%%line:%~1=%~2%%" for /f "delims=" %%X in ('"echo."%%line%%""') do %%~X ) ELSE echo. ) I've tried wrapping %MAINCSS% with no quotes, 1 quote, 2 quotes and all fail. No quotes and 2 quotes fail with "System can't find specified file" and 1 quote fails with "body shouldn't be used at this time" (translated from Chinese). Can anybody point me in the right direction here? Any help would be appreciate, thanks!

Well, in the end, somebody told me about Windows Scripting host and ended up using Javascript to write the string insertion part.