ant/src/etc/testcases/taskdefs/optional/replaceregexp.xml

<project name="test" default="def" basedir=".">

  <target name="def">
    <fail>This build file should only be run from within the testcase</fail>
  </target>

  <target name="setup">
    <copy file="replaceregexp.properties" tofile="test.properties" />
  </target>

  <target name="testReplace" depends="setup">
    <replaceregexp file="test.properties" byline="true">
      <regularexpression pattern="Old(.*)=(.*)" />
      <substitution expression="NewProp=\1\2" />
    </replaceregexp>
  </target>

  <target name="cleanup">
    <delete file="test.properties" />
  </target>

</project>