## Augment

Since Apache Ant 1.8.1

### Description

Modify an existing reference by adding nested elements or (re-)assigning properties mapped as XML attributes. This is an unusual task that makes use of Ant's internal processing mechanisms to reload a previously declared reference by means of the id attribute, then treats the declared `augment` element as though it were the original element.

### Parameters

Attribute | Description | Required
--- | --- | ---
id | The id of the reference to augment. If no such reference has been declared a `BuildException` is thrown. | Yes

Additional permissible attributes are dependent on the reference to be modified.

### Parameters specified as nested elements

Permissible nested elements are dependent on the reference to be modified.

### Examples

Given

    <fileset id="input-fs" dir="${basedir}"/>

invocation

    <augment id="input-fs" excludes="foo"/>

modifies the excludes attribute of `input-fs`, whereas

    <augment id="input-fs">
      <filename name="bar"/>
    </augment>

adds a `filename` selector to `input-fs`.