wangwei
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antliscence
forked from youys/ant

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<title>Truncate Task</title>
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<h2><a name="touch">Truncate</a></h2>
<h3>Description</h3>

<p>Set the length of one or more files, as the intermittently available
<code>truncate</code> Unix utility/function. In addition to working with
a single file, this Task can also work on
<a href="../CoreTypes/resource.html">resources</a> and resource collections.
<strong>Since Ant 1.7.1</strong>.
</p>

<h3>Parameters</h3>
<table border="1" cellpadding="2" cellspacing="0">
  <tr>
    <td valign="top"><b>Attribute</b></td>
    <td valign="top"><b>Description</b></td>
    <td align="center" valign="top"><b>Required</b></td>
  </tr>
  <tr>
    <td valign="top">file</td>
    <td valign="top">The name of the file.</td>
    <td valign="top" align="center">Unless a nested resource collection element
       has been specified.</td>
  </tr>
  <tr>
    <td valign="top">length</td>
    <td valign="top">Specifies the new file length to set. The following
    suffixes are supported:
    <ul>
      <li>K : Kilobytes (1024 bytes)</li>
      <li>M : Megabytes (1024 K)</li>
      <li>G : Gigabytes (1024 M)</li>
      <li>T : Terabytes (1024 G)</li>
      <li>P : Petabytes (1024 T)</li>
    </ul>
</td>
    <td valign="center" align="center" rowspan="2">One of these or neither.
      Specifying neither is equivalent to length="0".
    </td>
  </tr>
  <tr>
    <td valign="top">adjust</td>
    <td valign="top">Specifies the amount (and positive/negative direction)
      by which to adjust file lengths.</td>
  </tr>
  <tr>
    <td valign="top">create</td>
    <td valign="top">Whether to create nonexistent files.</td>
    <td valign="top" align="center">No, default <i>true</i>.</td>
  </tr>
  <tr>
    <td valign="top">mkdirs</td>
    <td valign="top">Whether to create nonexistent parent
       directories when creating new files.</td>
    <td valign="top" align="center">No, default <i>false</i>.</td>
  </tr>
</table>
<h3>Parameters specified as nested elements</h3>
<h4>any resource collection</h4>

<p>You can use any number of nested resource collection elements to
define the resources for this task and refer to resources defined
elsewhere.  <b>Note:</b> resources passed to this task are expected
to be filesystem-based.</p>

<h3>Examples</h3>

<pre>  &lt;truncate file="foo" /&gt;</pre>
<p>Sets the length of file <code>foo</code> to zero.</p>

<pre>  &lt;truncate file="foo" length="1K" /&gt;</pre>
<p>Sets the length of file <code>foo</code> to 1 kilobyte (1024 bytes).</p>

<pre>  &lt;truncate file="foo" adjust="1K" /&gt;</pre>
<p>Adjusts the length of file <code>foo</code> upward by 1 kilobyte.</p>

<pre>  &lt;truncate file="foo" adjust="-1M" /&gt;</pre>
<p>Adjusts the length of file <code>foo</code> downward by 1 megabyte.</p>

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