base file: d:\nlog-file.config

<?xml version="1.0" encoding="utf-8" ?><nlogxmlns="http://www.nlog-project.org/schemas/NLog.xsd"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd"><!-- This file will be included.--><!--  Note: Attributes on the "nlog" element are ignored for this file, the ones of the main config will be used.--><!-- the variable ${productName} must be defined in the main nlog.config-->    <targets>      <targetname="file1"xsi:type="File"fileName="D:\logs\${productName}\${shortdate}.log"layout="${time} [${level:uppercase=true}] |${logger}| ${message} ${exception}" />  </targets>  </nlog>

nlog.config

<?xml version="1.0" encoding="utf-8" ?><nlogxmlns="http://www.nlog-project.org/schemas/NLog.xsd"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd"><!-- override productName in includes, so it could be used in d:\nlog-file.config-->  <variablename="productName"value="myProduct"/>                              <includefile="D:\nlog-file.config"ignoreErrors="true" /><!-- note: will be set after the include are loaded-->  <variablename="myVar"value="myValue"/>        <rules>          <loggername="*"minlevel="Info"writeTo="file1"enabled="false" />         <loggername="PerformanceLogger"minlevel="Trace"writeTo="file1"enabled="false" /><!-- not enabled, only when tracing-->  </rules></nlog>