Ping "nant.sourceforge.net".

    <exec program="ping">
    <arg value="nant.sourceforge.net" />
</exec>

Execute a java application using IKVM.NET that requires the Apache FOP jars, and a set of custom jars.

<path id="fop-classpath">
        <pathelement file="${fop.dist.dir}/build/fop.jar" />
        <pathelement file="${fop.dist.dir}/lib/xercesImpl-2.2.1.jar" />
        <pathelement file="${fop.dist.dir}/lib/avalon-framework-cvs-20020806.jar" />
        <pathelement file="${fop.dist.dir}/lib/batik.jar" />
    </path>
    <exec program="ikvm.exe" useruntimeengine="true">
        <arg value="-cp" />
        <arg>
            <path>
                <pathelement dir="conf" />
                <path refid="fop-classpath" />
                <pathelement file="lib/mylib.jar" />
                <pathelement file="lib/otherlib.zip" />
            </path>
        </arg>
        <arg value="org.me.MyProg" />
    </exec>

Assuming the base directory of the build file is "c:\ikvm-test" and the value of the "fop.dist.dir" property is "c:\fop", then the value of the -cp argument that is passed toikvm.exe is "c:\ikvm-test\conf;c:\fop\build\fop.jar;conf;c:\fop\lib\xercesImpl-2.2.1.jar;c:\fop\lib\avalon-framework-cvs-20020806.jar;c:\fop\lib\batik.jar;c:\ikvm-test\lib\mylib.jar;c:\ikvm-test\lib\otherlib.zip" on a DOS-based system.

Use of nested NAnt.Core.Tasks.ExternalProgramBase.Arguments element(s) is advised over the NAnt.Core.Tasks.ExecTask.CommandLineArguments parameter, as it supports automatic quoting and can resolve relative to absolute paths.