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<h2><a name="replace">ReplaceRegExp</a></h2>
<h3>Description</h3>
<p>ReplaceRegExp is a directory based task for replacing the
occurrence of a given regular expression with a substitution pattern
in a selected file or set of files.</p>

<p>Similar to <a href="../CoreTypes/mapper.html#regexp-mapper">regexp
type mappers</a> this task needs a supporting regular expression
library and an implementation of
<code>org.apache.tools.ant.util.regexp.Regexp</code>.  Ant comes with
implementations for 
<a href="http://java.sun.com/j2se/1.4/docs/api/java/util/regex/package-summary.html" target="_top">the java.util.regex package of JDK 1.4</a>, 
<a href="http://jakarta.apache.org/regexp/" target="_top">jakarta-regexp</a> 
and <a href="http://jakarta.apache.org/oro/" target="_top">jakarta-ORO</a>,
but you will still need the library itself.</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">file for which the regular expression should be replaced.</td>
    <td align="center">Yes if no nested &lt;fileset&gt; is used</td>
  </tr>
  <tr>
    <td valign="top">match</td>
    <td valign="top">The regular expression pattern to match in the file(s)</td>
    <td align="center">Yes, if no nested &lt;regularexpression&gt; is used</td>
  </tr>
  <tr>
    <td valign="top">replace</td>
    <td valign="top">The substition pattern to place in the file(s) in place
                     of the regular expression.</td>
    <td align="center">Yes, if no nested &lt;substitution&gt; is used</td>
  </tr>
  <tr>
    <td valign="top">flags</td>
    <td valign="top">The flags to use when matching the regular expression.  For more
                     information, consult the Perl5 syntax<br />
                     g --> Global replacement.  Replace all occurances found<br />
                     i --> Case Insensitive.  Do not consider case in the match<br />
                     m --> Multiline.  Treat the string as multiple lines of input, using "^" and "$" as the start or end of any line, respectively, rather than start or end of string.<br />
                     s --> Singleline.  Treat the string as a single line of input, using "." to match any character, including a newline, which normally, it would not match.<br />
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">byline</td>
    <td valign="top">Process the file(s) one line at a time, executing the replacement
                     on one line at a time (<i>true/false</i>).  This is useful if you
                     want to only replace the first occurance of a regular expression on
                     each line, which is not easy to do when processing the file as a whole.
                     Defaults to <i>false</i>.</td>
    <td valign="top" align="center">No</td>
  </tr>
</table>
<h3>Examples</h3>
<pre>  &lt;replaceregexp file=&quot;${src}/build.properties&quot; 
                         match=&quot;OldProperty=(.*)&quot;
                         replace=&quot;NewProperty=\1&quot;
                         byline=&quot;true&quot; /&gt;
</pre>
<p>replaces occurrences of the property name &quot;OldProperty&quot;
 with &quot;NewProperty&quot; in a properties file, preserving the existing
value, in the file <code>${src}/build.properties</code></p>
<h3>Parameters specified as nested elements</h3>
<p>This task supports a nested <a href="../CoreTypes/fileset.html">FileSet</a> 
   element.</p>
<p>This task supports a nested <i>RegularExpression</i> element to specify
   the regular expression.  You can use this element to refer to a previously
   defined regular expression datatype instance.</p>
<blockquote>
     &lt;regularexpression id="id" pattern="expression" /&gt;<br />
     &lt;regularexpression refid="id" /&gt;
</blockquote>
<p>This task supports a nested <i>Substitution</i> element to specify
   the substitution pattern.  You can use this element to refer to a previously
   defined substition pattern datatype instance.</p>
<blockquote>
     &lt;substitution id="id" pattern="expression" /&gt;<br />
     &lt;substitution refid="id" /&gt;
</blockquote>
<h3>Examples</h3>
<blockquote>
  <pre>
&lt;replaceregexp byline=&quot;true&quot;&gt;
  &lt;regularexpression expression=&quot;OldProperty=(.*)&quot; /&gt;
  &lt;substitution expression=&quot;NewProperty=\1&quot; /&gt;
  &lt;fileset dir=&quot;.&quot;&gt;
   &lt;includes=&quot;*.properties&quot; /&gt;
  &lt;/fileset&gt;
 &lt;/replaceregexp&gt;
</pre></blockquote>
<p>replaces occurrences of the property name &quot;OldProperty&quot;
 with &quot;NewProperty&quot; in a properties file, preserving the existing
value, in all files ending in <code>.properties</code> in the current directory</p>

<hr>
<p align="center">Copyright &copy; 2000,2001 Apache Software Foundation. All rights
Reserved.</p>

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