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<title>Echoproperties Task</title>
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<h2 id="echoproperties">echoproperties</h2>
<h3>Description</h3>

<p>Displays all the current properties (or a subset of them specified by a
nested <code>&lt;propertyset&gt;</code>) in the project.  The output can be sent to a file if
desired.  This task can be used as a somewhat contrived means of returning data from an
<kbd>ant</kbd> invocation, but is really for debugging build
files.</p>

<h3>Parameters</h3>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>destfile</td>
    <td>If specified, the value indicates the name of the file to send the output of the statement
      to.  The generated output file is compatible for loading by any Java application as a property
      file.</td>
    <td>No; by default, output to the log</td>
  </tr>
  <tr>
    <td>prefix</td>
    <td>a prefix which is used to filter the properties: only properties whose names start with this
      prefix will be echoed.</td>
    <td>No</td>
  </tr>
  <tr>
    <td>regex</td>
    <td>a regular expression which is used to filter the properties: only those properties whose
      names match it will be echoed.</td>
    <td>No</td>
  </tr>
  <tr>
    <td>failonerror</td>
    <td>If an error occurs while writing the properties to a file, and this attribute is enabled,
      then a <code>BuildException</code> will be thrown, causing the build to fail.  If disabled,
      then IO errors will be reported as a log statement, and the build will continue without
      failure from this task.</td>
    <td>No; default is <q>true</q></td>
  </tr>
  <tr>
    <td>format</td>
    <td>One of <q>text</q> or <q>xml</q>.  Determines the output format.</td>
    <td>No; defaults to <q>text</q></td>
  </tr>
</table>

<h3>Parameters specified as nested elements</h3>

<h4>propertyset</h4>

<p><em>Since Ant 1.6</em>.</p>

<p>You can specify subsets of properties to be echoed
with <a href="../Types/propertyset.html">propertyset</a>s. Using <code>propertyset</code>s gives
more control on which properties will be picked up. The attributes <var>prefix</var>
and <var>regex</var> are just shortcuts that use <code>propertyset</code>s internally.</p>

<h3>Examples</h3>
<p>Report the current properties to the log.</p>
<pre>&lt;echoproperties/&gt;</pre>

<p>Report the current properties to the file <samp>my.properties</samp>, and fail the build if the
file could not be created or written to.</p>
<pre>&lt;echoproperties destfile="my.properties"/&gt;</pre>

<p>Report the current properties to the file <samp>my.properties</samp>, and log a message if the
file could not be created or written to, but still allow the build to continue.</p>
<pre>&lt;echoproperties destfile="my.properties" failonerror="false"/&gt;</pre>

<p>List all properties beginning with <samp>java.</samp></p>
<pre>&lt;echoproperties prefix="java."/&gt;</pre>

<p>Lists all properties beginning with <samp>java.</samp> using a
nested <code>&lt;propertyset/&gt;</code> which is an equivalent but longer way.</p>
<pre>
&lt;echoproperties&gt;
  &lt;propertyset&gt;
    &lt;propertyref prefix="java."/&gt;
  &lt;/propertyset&gt;
&lt;/echoproperties&gt;</pre>

<p>Lists all properties that contain <samp>ant</samp> in their names.</p>
<pre>&lt;echoproperties regex=".*ant.*"/&gt;</pre>

<p>The equivalent snippet with <code>&lt;propertyset/&gt;</code> is:</p>
<pre>
&lt;echoproperties&gt;
  &lt;propertyset&gt;
    &lt;propertyref regex=".*ant.*"/&gt;
  &lt;/propertyset&gt;
&lt;/echoproperties&gt;</pre>

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