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<title>Running Apache Ant</title>
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<body>

<h1>Running Apache Ant</h1>
<h2 id="commandline">Command Line</h2>

<p>If you've installed Apache Ant as described in
the <a href="install.html">Installing Ant</a> section, running Ant
from the command-line is simple: just type <kbd>ant</kbd>.</p>

<p>When no arguments are specified, Ant looks for
a <samp>build.xml</samp> file in the current directory and, if found,
uses that file as the build file and runs the target specified in
the <var>default</var> attribute of the <code>&lt;project&gt;</code>
tag.  To make Ant use a build file other than <samp>build.xml</samp>,
use the command-line option <kbd>-buildfile <i>file</i></kbd>,
where <code><i>file</i></code> is the name of the build file you want to use (or
a directory containing a <samp>build.xml</samp> file).</p>

<p>If you use the <kbd>-find [<i>file</i>]</kbd> option, Ant will
search for a build file first in the current directory, then in the
parent directory, and so on, until either a build file is found or the
root of the filesystem has been reached. By default, it will look for
a build file called <samp>build.xml</samp>. To have it search for a
build file other than <samp>build.xml</samp>, specify a file
argument. <strong>Note</strong>: If you include any other flags or
arguments on the command line after the <kbd>-find</kbd> flag, you
must include the file argument for the <kbd>-find</kbd> flag, even
if the name of the build file you want to find
is <samp>build.xml</samp>.</p>

<p>You can also set <a href="using.html#properties">properties</a> on
the command line.  This can be done with
the <kbd>-D<i>property</i>=<i>value</i></kbd> option,
where <em>property</em> is the name of the property,
and <em>value</em> is the value for that property. If you specify a
property that is also set in the build file (see
the <a href="Tasks/property.html">property</a> task), the value
specified on the command line will override the value specified in the
build file.  Defining properties on the command line can also be used
to pass in the value of environment variables; just
pass <kbd>-DMYVAR=%MYVAR%</kbd> (Windows)
or <kbd>-DMYVAR=$MYVAR</kbd> (Unix) to Ant. You can then access
these variables inside your build file as <code>${MYVAR}</code>.  You
can also access environment variables using
the <a href="Tasks/property.html">property</a>
task's <var>environment</var> attribute.</p>

<p>Options that affect the amount of logging output by Ant
are: <kbd>-quiet</kbd>, which instructs Ant to print less
information to the console; <kbd>-verbose</kbd>, which causes Ant to
print additional information to the console; <kbd>-debug</kbd>,
which causes Ant to print considerably more additional information;
and <kbd>-silent</kbd> which makes Ant print nothing but task output
and build failures (useful to capture Ant output by scripts).</p>

<p>It is also possible to specify one or more targets that should be
executed. When omitted, the target that is specified in
the <var>default</var> attribute of
the <a href="using.html#projects"><code>project</code></a> tag is
used.</p>

<p>The <kbd>-projecthelp</kbd> option prints out a list of the build
file's targets. Targets that include a <var>description</var>
attribute are listed as &quot;Main targets&quot;, those without
a <var>description</var> are listed as &quot;Other targets&quot;, then
the &quot;Default&quot; target is listed ("Other targets" are only
displayed if there are no main targets, or if Ant is invoked
in <kbd>-verbose</kbd> or <kbd>-debug</kbd> mode).</p>

<h3 id="options">Command-line Options Summary</h3>
<pre class="output">ant [options] [target [target2 [target3] ...]]
Options:
  -help, -h              print this message and exit
  -projecthelp, -p       print project help information and exit
  -version               print the version information and exit
  -diagnostics           print information that might be helpful to
                         diagnose or report problems and exit
  -quiet, -q             be extra quiet
  -silent, -S            print nothing but task outputs and build failures
  -verbose, -v           be extra verbose
  -debug, -d             print debugging information
  -emacs, -e             produce logging information without adornments
  -lib &lt;path&gt;            specifies a path to search for jars and classes
  -logfile &lt;file&gt;        use given file for log
    -l     &lt;file&gt;                ''
  -logger &lt;classname&gt;    the class which is to perform logging
  -listener &lt;classname&gt;  add an instance of class as a project listener
  -noinput               do not allow interactive input
  -buildfile &lt;file&gt;      use given buildfile
    -file    &lt;file&gt;              ''
    -f       &lt;file&gt;              ''
  -D&lt;property&gt;=&lt;value&gt;   use value for given property
  -keep-going, -k        execute all targets that do not depend
                         on failed target(s)
  -propertyfile &lt;name&gt;   load all properties from file with -D
                         properties taking precedence
  -inputhandler &lt;class&gt;  the class which will handle input requests
  -find &lt;file&gt;           (s)earch for buildfile towards the root of
    -s  &lt;file&gt;           the filesystem and use it
  -nice  number          A niceness value for the main thread:
                         1 (lowest) to 10 (highest); 5 is the default
  -nouserlib             Run ant without using the jar files from ${user.home}/.ant/lib
  -noclasspath           Run ant without using CLASSPATH
  -autoproxy             Java 5+ : use the OS proxies
  -main &lt;class&gt;          override Ant's normal entry point
</pre>
<p>For more information about <kbd>-logger</kbd>
and <kbd>-listener</kbd> see <a href="listeners.html">Loggers &amp;
Listeners</a>.
<p>For more information about <kbd>-inputhandler</kbd>
see <a href="inputhandler.html">InputHandler</a>.
<p>Easiest way of changing the exit-behaviour is subclassing the
original main class:</p>
<pre>
public class CustomExitCode extends org.apache.tools.ant.Main {
    protected void exit(int exitCode) {
        // implement your own behaviour, e.g. NOT exiting the JVM
    }
}
</pre>
<p>and starting Ant with access (<kbd>-lib <i>path-to-class</i></kbd>)
to this class.</p>

<h3 id="libs">Library Directories</h3>

<p>Prior to Ant 1.6, all jars in the <samp>ANT_HOME/lib</samp> would
be added to the <samp>CLASSPATH</samp> used to run Ant. This was done
in the scripts that started Ant. <em>Since Ant 1.6</em>, two
directories are scanned by default and more can be added as
required. The default directories scanned
are <samp>ANT_HOME/lib</samp> and a user specific
directory, <samp>${user.home}/.ant/lib</samp>. This arrangement allows
the Ant installation to be shared by many users while still allowing
each user to deploy additional jars.  Such additional jars could be
support jars for Ant's optional tasks or jars containing third-party
tasks to be used in the build. It also allows the main Ant
installation to be locked down which will please system
administrators.</p>

<p>Additional directories to be searched may be added by using
the <kbd>-lib</kbd> option.  The <kbd>-lib</kbd> option specifies
a search path. Any jars or classes in the directories of the path will
be added to Ant's classloader. The order in which jars are added to
the classpath is as follows:</p>

<ul>
  <li>jars in the order specified by the <kbd>-lib</kbd> options on the command line</li>
  <li>jars from <samp>${user.home}/.ant/lib</samp> (unless <kbd>-nouserlib</kbd> is set)</li>
  <li>jars from <samp>ANT_HOME/lib</samp></li>
</ul>

<p>Note that the <code>CLASSPATH</code> environment variable is passed
to Ant using a <kbd>-lib</kbd> option. Ant itself is started with a
very minimalistic classpath.  Ant should work perfectly well with an
empty <code>CLASSPATH</code> environment variable, something the
the <kbd>-noclasspath</kbd> option actually enforces. We get many more
support calls related to classpath problems (especially quoting
problems) than we like.</p>

<p>The location of <samp>${user.home}/.ant/lib</samp> is somewhat
dependent on the JVM. On Unix systems <samp>${user.home}</samp> maps
to the user's home directory whilst on recent versions of Windows it
will be somewhere such
as <code>C:\Users\<i>username</i>\.ant\lib</code>. You should consult
your JVM documentation for more details.</p>

<h3>Examples</h3>

<pre class="input">ant</pre>
<p>runs Ant using the <samp>build.xml</samp> file in the current
directory, on the default target.</p>

<pre class="input">ant -buildfile test.xml</pre>
<p>runs Ant using the <samp>test.xml</samp> file in the current
directory, on the default target.</p>

<pre class="input">ant -buildfile test.xml dist</pre>
<p>runs Ant using the <samp>test.xml</samp> file in the current
directory, on the target called <samp>dist</samp>.</p>

<pre class="input">ant -buildfile test.xml -Dbuild=build/classes dist</pre>
<p>runs Ant using the <samp>test.xml</samp> file in the current
directory, on the target called <samp>dist</samp>, setting
the <code>build</code> property to the value <q>build/classes</q>.</p>

<pre class="input">ant -lib /home/ant/extras</pre>
<p>runs Ant picking up additional task and support jars from
the <samp>/home/ant/extras</samp> location</p>

<pre class="input">ant -lib one.jar;another.jar</pre>
<pre class="input">ant -lib one.jar -lib another.jar</pre>
<p>adds two jars to Ants classpath.</p>

<h3 id="files">Files</h3>

<p>The Ant wrapper script for Unix will source (read and evaluate) the
file <samp>~/.antrc</samp> before it does anything. On Windows, the
Ant wrapper batch-file invokes <samp>%HOME%\antrc_pre.bat</samp> at
the start and <samp>%HOME%\antrc_post.bat</samp> at the end.  You can
use these files, for example, to set/unset environment variables that
should only be visible during the execution of Ant.  See the next
section for examples.</p>

<h3 id="envvars">Environment Variables</h3>

<p>The wrapper scripts use the following environment variables (if set):</p>

<ul>
  <li><code>JAVACMD</code>&mdash;full path of the Java executable.  Use this
  to invoke a different JVM than <samp>JAVA_HOME/bin/java(.exe)</samp>.</li>

  <li><code>ANT_OPTS</code>&mdash;command-line arguments that should be
  passed to the JVM. For example, you can define system properties or set
  the maximum Java heap size here.</li>

  <li><code>ANT_ARGS</code>&mdash;Ant command-line arguments. For example,
  set <code>ANT_ARGS</code> to point to a different logger, include a
  listener, and to include the <kbd>-find</kbd> flag.<br/>
  <strong>Note</strong>: If you include <kbd>-find</kbd>
  in <code>ANT_ARGS</code>, you should include the name of the build file
  to find, even if the file is called <samp>build.xml</samp>.</li>
</ul>

<h3 id="sysprops">Java System Properties</h3>
<p>Some of Ant's core classes can be configured via system properties.</p>
<p>Here is the result of a search through the codebase. Because system
properties are available via Project instance, I searched for them with a</p>
<pre class="input">grep -r -n "getPropert" * &gt; ..\grep.txt</pre>
<p>command. After that I filtered out the often-used but
not-so-important values (most of them read-only
values): <code>path.separator</code>, <code>ant.home</code>, <code>basedir</code>,
<code>user.dir</code>, <code>os.name</code>, <code>line.separator</code>,
<code>java.home</code>, <code>java.version</code>, <code>java.version</code>,
<code>user.home</code>, <code>java.class.path</code><br/>
And I filtered out the <code>getPropertyHelper</code> access.</p>

<table>
<tr>
  <th scope="col">property name</th>
  <th scope="col">valid values/default value</th>
  <th scope="col">description</th>
</tr>
<tr>
  <td><code>ant.build.javac.source</code></td>
  <td>Source-level version number</td>
  <td>Default <var>source</var> value
  for <code>&lt;javac&gt;</code>/<code>&lt;javadoc&gt;</code></td>
</tr>
<tr>
  <td><code>ant.build.javac.target</code></td>
  <td>Class-compatibility version number</td>
  <td>Default <var>target</var> value for <code>&lt;javac&gt;</code></td>
</tr>
<tr>
  <td><code>ant.executor.class</code></td>
  <td>classname; default is <q>org.<wbr>apache.<wbr>tools.<wbr>ant.<wbr>helper.<wbr>DefaultExecutor</q></td>
  <td><em>Since Ant 1.6.3</em> Ant will delegate Target invocation to
  the <code class="code">org.apache.tools.ant.Executor</code>
  implementation specified here.</td>
</tr>
  <tr>
  <td><code>ant.file</code></td>
  <td>read only: full filename of the build file</td>
  <td>This is set to the name of the build
  file. In <a href="Tasks/import.html">&lt;import&gt;-ed</a> files,
  this is set to the containing build file.</td>
</tr>
  <tr>
  <td><code>ant.file.*</code></td>
  <td>read only: full filename of the build file of Ant projects</td>
  <td>This is set to the name of a file by project; this lets you
  determine the location
  of <a href="Tasks/import.html">&lt;import&gt;-ed</a> files.</td>
</tr>
  <tr>
  <td><code>ant.input.properties</code></td>
  <td>filename (required)</td>
  <td>Name of the file holding the values for
  the <a href="inputhandler.html">PropertyFileInputHandler</a>.</td>
</tr>
<tr>
  <td><code>ant.logger.defaults</code></td>
  <td>filename (optional, default <q>/org/<wbr>apache/<wbr>tools/<wbr>ant/<wbr>listener/<wbr>defaults.properties</q>)</td>
  <td>Name of the file holding the color mappings for
  the <a href="listeners.html#AnsiColorLogger">AnsiColorLogger</a>.</td>
</tr>
<tr>
  <td><code>ant.netrexxc.*</code></td>
  <td>several formats</td>
  <td>Use specified values as defaults
  for <a href="Tasks/netrexxc.html">netrexxc</a>.</td>
</tr>
<tr>
  <td><code>ant.PropertyHelper</code></td>
  <td>Ant reference name (optional)</td>
  <td>Specify the PropertyHelper to use. The object must be of the
  type <code class="code">org.apache.tools.ant.PropertyHelper</code>. By
  default, an object
  of <code class="code">org.apache.tools.ant.PropertyHelper</code>
  will be used as PropertyHelper.</td>
</tr>
<tr>
  <td><code>ant.regexp.regexpimpl</code></td>
  <td>classname</td>
  <td>classname for a RegExp implementation; by default the <code>java.util.regex</code>
  implementation; <a href="Types/mapper.html#regexp-mapper">RegExp
  Mapper</a> "Choice of regular expression implementation".</td>
</tr>
<tr>
  <td><code>ant.reuse.loader</code></td>
  <td>boolean</td>
  <td>allow to reuse classloaders used
  in <code class="code">org.apache.tools.ant.util.ClasspathUtil</code>.</td>
</tr>
<tr>
  <td><code>ant.XmlLogger.stylesheet.uri</code></td>
  <td>filename (default <q>log.xsl</q>)</td>
  <td>Name for the stylesheet to include in the logfile
  by <a href="listeners.html#XmlLogger">XmlLogger</a>.</td>
</tr>
<tr>
  <td><code>build.compiler</code></td>
  <td>name</td>
  <td>Specify the default compiler to use;
  see <a href="Tasks/javac.html">javac</a>, <a href="Tasks/ejb.html#ejbjar_weblogic">EJB
  Tasks</a> (<var>compiler</var>
  attribute), <a href="Tasks/javah.html">javah</a>.</td>
</tr>
<tr>
  <td><code>build.compiler.emacs</code></td>
  <td>boolean (default <q>false</q>)</td>
  <td>Enable emacs-compatible error messages;
  see <a href="Tasks/javac.html#jikes">javac</a> "Jikes Notes".</td>
</tr>
<tr>
  <td><code>build.compiler.fulldepend</code></td>
  <td>boolean (default false)</td>
  <td>Enable full dependency checking;
  see <a href="Tasks/javac.html#jikes">javac</a> "Jikes Notes".</td>
</tr>
<tr>
  <td><code>build.compiler.jvc.extensions</code></td>
  <td><em><u>Deprecated</u></em></td>
  <td>Enable Microsoft extensions of their Java compiler;
  see <a href="Tasks/javac.html#jvc">javac</a> "Jvc Notes".</td>
</tr>
<tr>
  <td><code>build.compiler.pedantic</code></td>
  <td>boolean (default <q>false</q>)</td>
  <td>Enable pedantic warnings;
  see <a href="Tasks/javac.html#jikes">javac</a> "Jikes Notes".</td>
</tr>
<tr>
  <td><code>build.compiler.warnings</code></td>
  <td><em><u>Deprecated</u></em></td>
  <td>See <a href="Tasks/javac.html#jikes">javac</a> "Jikes Notes"</td>
</tr>
<tr>
  <td><code>build.rmic</code></td>
  <td>name</td>
  <td>Control the <a href="Tasks/rmic.html">rmic</a> compiler</td>
</tr>
<tr>
  <td><code>build.sysclasspath</code></td>
  <td>No default value</td>
  <td>See <a href="sysclasspath.html">its dedicated page</a></td>
</tr>
<tr>
  <td><code>file.encoding</code></td>
  <td>name of a supported character set (e.g. UTF-8, ISO-8859-1, US-ASCII)</td>
  <td>use as default character set of email messages; use as default
  for <var>srcencoding</var>, <var>destencoding</var>
  and <var>bundleencoding</var>
  in <a href="Tasks/translate.html">translate</a><br/> see JavaDoc
  of <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html"
  target="_top">java.nio.charset.Charset</a> for more information
  about character sets (not used in Ant, but has nice docs).</td>
</tr>
<tr>
  <td><code>jikes.class.path</code></td>
  <td>path</td>
  <td>The specified path is added to the classpath if Jikes is used as compiler.</td>
</tr>
<tr>
  <td><code>MailLogger.properties.file</code>, <code>MailLogger.*</code></td>
  <td>filename (optional, defaults derived from Project instance)</td>
  <td>Name of the file holding properties for sending emails by
  the <a href="listeners.html#MailLogger">MailLogger</a>. Override
  properties set inside the buildfile or via command line.</td>
</tr>
<tr>
  <td><code>org.apache.tools.ant.ProjectHelper</code></td>
  <td>classname (optional, default <q>org.<wbr>apache.<wbr>tools.<wbr>ant.<wbr>ProjectHelper2</q>)</td>
  <td>specifies the classname to use as ProjectHelper. The class must
  extend <code class="code">org.apache.tools.ant.ProjectHelper</code>.</td>
</tr>
<tr>
  <td><code>org.apache.tools.ant.ArgumentProcessor</code></td>
  <td>classname (optional)</td>
  <td>specifies the classname to use as ArgumentProcessor. The class
  must extend <code class="code">org.apache.tools.ant.ArgumentProcessor</code>.</td>
</tr>
<tr>
  <td><code>websphere.home</code></td>
  <td>path</td>
  <td>Points to home directory of WebSphere;
  see <a href="Tasks/ejb.html#ejbjar_websphere">EJB Tasks</a></td>
</tr>
<tr>
  <td><code>XmlLogger.file</code></td>
  <td>filename (default <q>log.xml</q>)</td>
  <td>Name for the logfile
  for <a href="listeners.html#MailLogger">MailLogger</a>.</td>
</tr>
<tr>
  <td><code>ant.project-helper-repo.debug</code></td>
  <td>boolean (default <q>false</q>)</td>
  <td>Set it to <q>true</q> to enable debugging with
  Ant's <a href="projecthelper.html#repository">ProjectHelper internal
  repository</a>.</td>
</tr>
<tr>
  <td><code>ant.argument-processor-repo.debug</code></td>
  <td>boolean (default <q>false</q>)</td>
  <td>Set it to <q>true</q> to enable debugging with
  Ant's <a href="argumentprocessor.html#repository">ArgumentProcessor
  internal repository</a>.</td>
</tr>
<tr>
  <td><code>ant.tstamp.now</code></td>
  <td>number, seconds since the epoch (midnight 1970-01-01)</td>
  <td rowspan="2">The value to use as current time and date
  for <code>&lt;tstamp&gt;</code></td>
</tr>
<tr>
  <td><code>ant.tstamp.now.iso</code></td>
  <td>ISO-8601 timestamp string like <code>1972-04-17T08:07:00Z</code></td>
</tr>
<tr>
  <td><code>java.io.tmpdir</code></td>
  <td>path</td>
  <td>Some tasks need to create temporary files and will write them to
  the directory specified by this property. This property is set by
  the Java VM but can be overridden when Ant is started.<br/>
  See also <a href="#tmpdir">Temporary Directories</a>.</td>
</tr>
<tr>
  <td><code>ant.tmpdir</code></td>
  <td>path</td>
  <td><em>Since Ant 1.10.8</em><br/>
  Some tasks need to create temporary files and will write them to
  the directory specified by this property. This property takes
  precedence over <code>java.io.tmpdir</code> if it has been
  set. Unlike <code>java.io.tmpdir</code> this property can be set
  from within the build file.<br/>
  See also <a href="#tmpdir">Temporary Directories</a>.</td>
</tr>
<tr>
  <td><code>ant.disable.graal.nashorn.compat</code></td>
  <td>boolean (default <q>false</q>)</td>
  <td><em>Since Ant 1.10.9</em><br/>
  By default Ant will enable GraalVM JavaScript's Nashorn
  compatibility mode for <code>script</code> and friends. You can
  disable this behavior by setting this property to <q>true</q>.<br/>
  See also the <a href="Tasks/script.html">script task manual</a>.</td>
</tr>
</table>

<p>
If new properties get added (it happens), expect them to appear under
the <code>ant.</code> and <code>org.apache.tools.ant.</code> prefixes,
unless the developers have a very good reason to use another
prefix. Accordingly, please avoid using properties that begin with
these prefixes. This protects you from future Ant releases breaking
your build file.
</p>
<h3>return code</h3>
<p>
Ant start up scripts (in their Windows and Unix version) return the
return code of the <code>java</code> program. So a successful build
returns <q>0</q>, failed builds return other values.
</p>

<h2 id="tmpdir">Temporary Directories</h2>

Some Ant tasks and types need to create temporary files. By default
they use the default temporary directory of the Java VM they are
running in - which can be set by setting the system
property <code>java.io.tmpdir</code>. The default value of it depends
on the platform and the JVM implementation.</p>

<p>Setting a system property when invoking Ant is not straight forward
  as the corresponding command line arguments must be sent to the Java
  executable rather than Ant's main class. When using
  the <code>ant(.cmd)</code> wrapper scripts you can do so with the
  help of the <code>ANT_OPTS</code> environment variable.</p>

<p>Starting with Ant 1.10.8 we've introduced a new Ant
  property <code>ant.tmpdir</code> that takes precedence
  over <code>java.io.tmpdir</code> when set. As this is a normal Ant
  property it can be set via the command line or even from within a
  build file.</p>

<p>Tasks and types using the temporary directory will state the fact
  inside of their respective manual page. In addition every execution
  of an external command on OpenVMS will create a temporary file
  holding a DCL script that invokes the actual command.</p>

<p>Starting with Ant 1.10.9 Ant will try to create a build process
  specific temporary directory inside <code>java.io.tmpdir</code> with
  permissions set to be accessible by the current user only and use
  that if <code>ant.tmpdir</code> has not been set and Ant is able to
  set permissions on the filesystem in question.</p>

<p>Tasks not provided with the Ant distribution will ignore
  the <code>ant.tmpdir</code> property or the process subdirectory and
  use <code>java.io.tmpdir</code> unless they have been adapted to the
  changed API of Ant 1.10.8.</p>

<p><b>Security Note:</b> Using the default temporary directory
specified by <code>java.io.tmpdir</code> can result in the leakage of
sensitive information or possibly allow an attacker to inject source
files into the build process. This is especially true in multi-user
environments. It is recommended that <code>ant.tmpdir</code> be set to
a directory owned by the user running Ant with 0700 permissions. Ant
1.10.8 and later will try to make temporary files created by it only
readable/writable by the current user but may silently fail to do so
depending on the OS and filesystem.</p>

<h2 id="cygwin">Cygwin Users</h2>
<p>
Unix launch script that come with Ant works correctly with Cygwin. You
should not have any problems launching Ant from the Cygwin shell. It
is important to note, however, that once Ant is running it is part of
the JDK which operates as a native Windows application. The JDK is not
a Cygwin executable, and it therefore has no knowledge of Cygwin
paths, etc. In particular when using the <code>&lt;exec&gt;</code>
task, executable names such as <q>/bin/sh</q> will not work, even
though these work from the Cygwin shell from which Ant was
launched. You can use an executable name such as <q>sh</q> and rely on
that command being available in the Windows path.

<h2 id="os2">OS/2 Users</h2>
<p>
The OS/2 launch script was developed to perform complex tasks. It has
two parts: <kbd>ant.cmd</kbd> which calls Ant
and <kbd>antenv.cmd</kbd> which sets the environment for Ant.  Most
often you will just call <kbd>ant.cmd</kbd> using the same command
line options as described above. The behaviour can be modified by a
number of ways explained below.
</p>

<p>
Script <kbd>ant.cmd</kbd> first verifies whether the Ant environment
is set correctly. The requirements are:
</p>
<ol>
<li>Environment variable <code>JAVA_HOME</code> is set.</li>
<li>Environment variable <code>ANT_HOME</code> is set.</li>
<li>Environment variable <code>CLASSPATH</code> is set and contains at least one element from
<code>JAVA_HOME</code> and at least one element from <code>ANT_HOME</code>.</li>
</ol>

<p>
If any of these conditions is violated, script <kbd>antenv.cmd</kbd>
is called. This script first invokes configuration scripts if there
exist: the system-wide configuration <kbd>antconf.cmd</kbd> from
the <samp>%ETC%</samp> directory and then the user
configuration <kbd>antrc.cmd</kbd> from the <samp>%HOME%</samp>
directory. At this moment both <code>JAVA_HOME</code>
and <code>ANT_HOME</code> must be defined
because <kbd>antenv.cmd</kbd> now adds <samp>classes.zip</samp>
or <samp>tools.jar</samp> (depending on version of JVM) and everything
from <samp>%ANT_HOME%\lib</samp> except <samp>ant-*.jar</samp>
to <code>CLASSPATH</code>. Finally <kbd>ant.cmd</kbd> calls
per-directory configuration <kbd>antrc.cmd</kbd>. All settings made
by <kbd>ant.cmd</kbd> are local and are undone when the script
ends. The settings made by <kbd>antenv.cmd</kbd> are persistent
during the lifetime of the shell (of course unless called
automatically from <kbd>ant.cmd</kbd>). It is thus possible to
call <kbd>antenv.cmd</kbd> manually and modify some settings before
calling <kbd>ant.cmd</kbd>.
</p>

<p>
Scripts <kbd>envset.cmd</kbd> and <kbd>runrc.cmd</kbd> perform
auxiliary tasks. All scripts have some documentation inside.
</p>

<h2 id="background">Running Ant as a background process on Unix(-like) systems</h2>

<p>
If you start Ant as a background process (like in <kbd>ant
&amp;</kbd>) and the build process creates another process, Ant will
immediately try to read from standard input, which in turn will most
likely suspend the process.  In order to avoid this, you must redirect
Ant's standard input or explicitly provide input to each spawned
process via the input related attributes of the corresponding tasks.
</p>

<p>
Tasks that create such new processes
include <code>&lt;exec&gt;</code>, <code>&lt;apply&gt;</code>
or <code>&lt;java&gt;</code> when the <var>fork</var> attribute
is <q>true</q>.
</p>

<h2 id="viajava">Running Ant via Java</h2>
<p>
If you have installed Ant in the do-it-yourself way, Ant can be
started from one of two entry points:
</p>

<pre class="input">java -Dant.home=c:\ant org.apache.tools.ant.Main [options] [target]</pre>
<pre class="input">java -Dant.home=c:\ant org.apache.tools.ant.launch.Launcher [options] [target]</pre>

<p>
The first method runs Ant's traditional entry point. The second method
uses the Ant Launcher introduced in Ant 1.6. The former method does
not support the <kbd>-lib</kbd> option and all required classes are
loaded from the <code>CLASSPATH</code>. You must ensure that all
required jars are available. At a minimum the <code>CLASSPATH</code>
should include:
</p>

<ul>
<li><samp>ant.jar</samp> and <samp>ant-launcher.jar</samp></li>
<li>jars/classes for your XML parser</li>
<li>the JDK's required jar/zip files</li>
</ul>

<p>
The latter method supports
the <kbd>-lib</kbd>, <kbd>-nouserlib</kbd>, <kbd>-noclasspath</kbd>
options and will load jars from the
specified <code>ANT_HOME</code>. You should start the latter with the
most minimal classpath possible, generally just
the <samp>ant-launcher.jar</samp>.
</p>

<p id="viaant">
Ant can be started in Ant via the <code>&lt;java&gt;</code> command.
Here is an example:
</p>
<pre>
&lt;java classname="org.apache.tools.ant.launch.Launcher"
      fork="true"
      failonerror="true"
      dir="${sub.builddir}"
      timeout="4000000"
      taskname="startAnt"&gt;
    &lt;classpath&gt;
        &lt;pathelement location="${ant.home}/lib/ant-launcher.jar"/&gt;
    &lt;/classpath&gt;
    &lt;arg value="-buildfile"/&gt;
    &lt;arg file="${sub.buildfile}"/&gt;
    &lt;arg value="-Dthis=this"/&gt;
    &lt;arg value="-Dthat=that"/&gt;
    &lt;arg value="-Dbasedir=${sub.builddir}"/&gt;
    &lt;arg value="-Dthe.other=the.other"/&gt;
    &lt;arg value="${sub.target}"/&gt;
&lt;/java&gt;
</pre>

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