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<h2><a name="exec">Exec</a></h2>
<h3>Description</h3>
<p>Executes a system command. When the <i>os</i> attribute is specified, then
the command is only executed when Ant is run on one of the specified operating
systems.</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">command</td>
<td valign="top">the command to execute with all command line
arguments. <b>deprecated, use executable and nested
<code><arg></code> elements instead</b>.</td>
<td align="center" rowspan="2">Exactly one of the two.</td>
</tr>
<tr>
<td valign="top">executable</td>
<td valign="top">the command to execute without any command line
arguments.</td>
</tr>
<tr>
<td valign="top">dir</td>
<td valign="top">the directory in which the command should be executed.</td>
<td align="center" valign="top">No</td>
</tr>
<tr>
<td valign="top">os</td>
<td valign="top">list of Operating Systems on which the command may be
executed.</td>
<td align="center" valign="top">No</td>
</tr>
<tr>
<td valign="top">output</td>
<td valign="top">the file to which the output of the command should be
redirected.</td>
<td align="center" valign="top">No</td>
</tr>
<tr>
<td valign="top">timeout</td>
<td valign="top">Stop the command if it doesn't finish within the
specified time (given in milliseconds).</td>
<td align="center" valign="top">No</td>
</tr>
<tr>
<td valign="top">failonerror</td>
<td valign="top">Stop the buildprocess if the command exits with a
returncode other than 0. Defaults to false</td>
<td align="center" valign="top">No</td>
</tr>
<tr>
<td valign="top">newenvironment</td>
<td valign="top">Do not propagate old environment when new environment
variables are specified.</td>
<td align="center" valign="top">No, default is <i>false</i></td>
</tr>
</table>
<h3>Examples</h3>
<blockquote>
<pre>
<exec dir="${src}" executable="cmd.exe" os="Windows 2000" output="dir.txt">
<arg line="/c dir"/>
</exec></pre>
</blockquote>
<h3>Parameters specified as nested elements</h3>
<h4>arg</h4>
<p>Command line arguments should be specified as nested
<code><arg></code> elements. See <a
href="../using.html#arg">Command line arguments</a>.</p>
<h4><a name="env">env</a></h4>
<p>It is possible to specify environment variables to pass to the
system command via nested <code><env></code> elements.</p>
<p>Please note that the environment of the current Ant process is
<b>not</b> passed to the system command if you specify variables using
<code><env></code>.</p>
<table border="1" cellpadding="2" cellspacing="0">
<tr>
<td valign="top"><b>Attribute</b></td>
<td valign="top"><b>Description</b></td>
<td align="center" valign="top"><b>Required</b></td>
</tr>
<tr>
<td valign="top">key</td>
<td valign="top">The name of the environment variable.</td>
<td align="center" valign="top">Yes</td>
</tr>
<tr>
<td valign="top">value</td>
<td valign="top">The literal value for the environment variable.</td>
<td align="center" rowspan="3">Exactly one of these.</td>
</tr>
<tr>
<td valign="top">path</td>
<td valign="top">The value for a PATH like environment
variable. You can use ; or : as path separators and Ant will
convert it to the platform's local conventions.</td>
</tr>
<tr>
<td valign="top">file</td>
<td valign="top">The value for the environment variable. Will be
replaced by the absolute filename of the file by Ant.</td>
</tr>
</table>
<h5>Examples</h5>
<blockquote><pre>
<exec executable="emacs" >
<env key="DISPLAY" value=":1.0"/>
</exec>
</pre></blockquote>
<p>starts <code>emacs</code> on display 1 of the X Window System.</p>
<blockquote><pre>
<exec ... >
<env key="PATH" path="${java.library.path}:${basedir}/bin"/>
</exec>
</pre></blockquote>
<p>adds <code>${basedir}/bin</code> to the <code>PATH</code> of the
system command.</p>
<p><b>Note:</b> Although it may work for you to specify arguments using
a simple arg-element and separate them by spaces it may fail if you switch to
a newer version of the JDK. JDK < 1.2 will pass these as separate arguments
to the program you are calling, JDK >= 1.2 will pass them as a single
argument and cause most calls to fail.</p>
<p><b>Note2:</b> If you are using Ant on Windows and a new DOS-Window pops up
for every command which is executed this may be a problem of the JDK you are using.
This problem may occur with all JDK's < 1.2.</p>
<hr>
<p align="center">Copyright © 2000,2001 Apache Software Foundation. All rights
Reserved.</p>
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