Sample Ant build.xml file for concat and minifying CSS & JS files by Addy Osmani

build.xml

<?xml version="1.0" encoding="utf-8"?>
<project name="tutorialProject" default="prod" basedir="/Users/addy/buildTut/">

    <description>Client-side ANT build file example</description>

    <target name="-load.properties"
        description="Set properties for this build">
        <!--YUI Compressor location-->
        <property name="yui.dir" value="${basedir}/yuicompressor/build/yuicompressor-2.4.2.jar"/>
        <!--Source JS dir-->
        <property name="src.js.dir" value="${basedir}/js"/>
        <!--Source CSS dir-->
        <property name="src.css.dir" value="${basedir}/css"/>
        <!--Source Lint/Hint dir-->
        <property name="jslint.js" value="${basedir}/lint/jshint.js"/>
        <!--Rhino dir-->
        <property name="js.jar" value="${basedir}/lint/rhino/js.jar"/>
        <!--Output dir-->
        <property name="build.dir" value="build"/>
        <!--Build version information -->
        <property name="build.major" value="1"/>
        <property name="build.minor" value="1"/>
    </target>



    <!--Create build directories-->
    <target name="-init" depends="-load.properties"
        description="Create build directory structure">
        <!--Create the time stamp for the new build-->
        <tstamp>
            <format property="TODAY" pattern="EEE, d MMM yyyy HH:mm:ss Z"/>
        </tstamp>
        
        <!--Delete previous build files-->
        <delete dir="${build.dir}"/>
        
        <!--Recreate the build directories-->
        <mkdir dir="${build.dir}"/>
        <mkdir dir="${build.dir}/js"/>
        <mkdir dir="${build.dir}/css"/>
        
        <!--Log the build timestamps to file-->
        <echo file="${build.dir}/js/tstamp.txt" append="false">Build Date: ${TODAY}</echo>
        <echo file="${build.dir}/css/tstamp.txt" append="false">Build Date: ${TODAY}</echo>
    </target>


   <!--JS Lint-->
	<target depends="-init" name="-js.lint">
	    <pathconvert pathsep=" " property="jsfiles">
	        <fileset dir="${build.dir}/js/">
	            <include name="*.js"/>
	        </fileset>
	    </pathconvert>
	    <exec dir="${build.dir}/js/" executable="java" failonerror="true">
	        <arg line="-jar ${js.jar} ${jslint.js} ${jsfiles}"/>
	    </exec>
	    <echo>Finished</echo>
	</target>
	
	
    <!--Concatenate JS files-->
    <target name="-js.concatenate" depends="-js.lint" 
        description="Concatenates specified JavaScript files">
        <concat destfile="${build.dir}/js/concat.js">
            <fileset 
                dir="${src.js.dir}"
                includes="*.js" 
                excludes="first.js, second.js"/>
        </concat>
        <echo>Finished</echo>
    </target>

	    
    
    <!--Concatenate CSS files-->
    <target name="-css.concatenate" depends="-init" 
        description="Concatenates specified CSS files">
        <concat destfile="${build.dir}/css/styles.css">
            <!--first.css and second.css should be first in the concatenated file-->
            <filelist 
                dir="${src.css.dir}" 
                files="first.css, second.css"/>
            <!--All of the other files in the directory should appear after.-->
            <fileset 
                dir="${src.css.dir}"
                includes="*.css" 
                excludes="first.css, second.css"/>
        </concat>
        <echo>Finished</echo>
    </target>



    <!--Minify JS files-->
    <target name="-js.minify" depends="-js.concatenate" 
        description="Minifies JavaScript files">
        <apply executable="java" parallel="false" dest="${build.dir}/js">
            <fileset 
                dir="${build.dir}/js" 
                includes="concat.js"/>
            <arg line="-jar"/>
            <arg path="${yui.dir}"/>
            <srcfile/>
            <arg line="-o"/>
            <mapper type="glob" from="*.js" to="*-min.js"/>
            <targetfile/>
        </apply>
        <echo>Finished</echo>
    </target>



    <!--Minify CSS files-->
    <target name="-css.minify" depends="-css.concatenate" 
        description="Minifies CSS files">
        <apply executable="java" parallel="false"  dest="${build.dir}/css">
            <fileset 
                dir="${build.dir}/css" 
                includes="styles.css"/>
            <arg line="-jar"/>
            <arg path="${yui.dir}"/>
            <arg line="--line-break 0"/>
            <srcfile/>
            <arg line="-o"/>
            <mapper type="glob" from="*.css" to="*-min.css"/>
            <targetfile/>
        </apply>
        <echo>Finished</echo>
    </target>


    <!--Build-->
    <target name="prod" 
        description="Builds project files for production use"
        depends="
            -load.properties, 
            -init, 
            -js.concatenate,
            -js.lint, 
            -css.concatenate, 
            -js.minify, 
            -css.minify">
    </target>
</project>

Hello there, what about line 15 and 16 ?