Running AjaxMin on sets of files at build time

project.msbuild

<Target Name="AfterBuild">
    <CallTarget Targets="MinifyJs" />
</Target>

<PropertyGroup>
    <AjaxMin>"C:\Program Files (x86)\Microsoft\Microsoft Ajax Minifier\AjaxMin.exe"</AjaxMin>
</PropertyGroup>

<Target Name="MinifyJs">
    <ItemGroup>
        <File Include="$(MSBuildProjectDirectory)\Scripts\*.minmejs" />
    </ItemGroup>
    <MsBuild Projects="$(MSBuildProjectFile)" Targets="_MinifyJs" Properties="JsMin=%(File.Identity);" Condition=" '%(File.Identity)' != '' " />
</Target>

<Target Name="_MinifyJs">
    <ItemGroup>
        <JsFile Include="$(JsMin)" />
    </ItemGroup>
    <ReadLinesFromFile File="$(JsMin)">
        <Output TaskParameter="Lines" ItemName="FileContents" />
    </ReadLinesFromFile>
    <Exec Command="$(AjaxMin) @(FileContents-&gt;'%(Identity)', ' ') -out %(JsFile.Filename).min.js -clobber" WorkingDirectory="%(JsFile.RootDir)%(JsFile.Directory)" />
</Target>

script.minmejs

# one js filename per line to be minified/combined.  file will be renamed from xxx.minmejs to xxx.min.js
script.js
lib/external-library.js
util.js