strip till delimeter in ant - ant

Question

I have a target which will run a executable and get a version. But I need to remove stuff till the delimeter. Help me please.
<target name="tomcatVersion">
<exec executable="${WT_HOME}/tomcat/bin/catalina.bat" outputproperty="tomcat.version">
<arg value="version" />
<redirector>
<outputfilterchain>
<tokenfilter>
<containsstring contains="Server number:"/>
</tokenfilter>
</outputfilterchain>
</redirector>
</exec>
<echo message="${tomcat.version}"/>
</target>

Answer 1

[Update: single step loadresource method with thanks to Matt]
You could do this by reading the output of the executable into a property and then filtering the property through a replaceregexp token filter to extract the string you require. For example:
<project default="get-version">
<target name="get-version">
<exec executable="bash" outputproperty="version.output">
<arg value="ant"/>
<arg value="-version"/>
</exec>
<loadresource property="version">
<string value="${version.output}"/>
<filterchain>
<tokenfilter>
<replaceregex pattern="[^\d]*(\d.\d.\d).*" replace="\1"/>
</tokenfilter>
<striplinebreaks/>
</filterchain>
</loadresource>
<echo level="info" message="version is: '${version}'"/>
</target>
</project>
Sample output:
$ ant -version
Apache Ant(TM) version 1.8.2 compiled on December 20 2010
$ ant
Buildfile: build.xml
get-version:
[echo] version is: '1.8.2'
BUILD SUCCESSFUL
Total time: 2 seconds
(I am using ant -version as a handy stand in for whatever executable you are running. I am aware that Ant version can be got from Ant properties.)
With older versions of Ant (<1.7) you could do this in two steps:
Write the output of the executable to file
Read the file through a replaceregexp token filter
For example:
<project default="get-version">
<target name="get-version">
<exec executable="bash" output="version.out">
<arg value="ant"/>
<arg value="-version"/>
</exec>
<loadfile property="version" srcfile="version.out">
<filterchain>
<tokenfilter>
<replaceregex pattern="[^\d]*(\d.\d.\d).*" replace="\1"/>
</tokenfilter>
<striplinebreaks/>
</filterchain>
</loadfile>
<echo level="info" message="version is: '${version}'"/>
</target>
</project>
Sample output
$ ant -version
Apache Ant version 1.6.5 compiled on June 2 2005
$ ant
Buildfile: build.xml
get-version:
[echo] version is: '1.6.5'
BUILD SUCCESSFUL
Total time: 2 seconds

Answer 2

The exec task has 3 attributes to catch the output from an executable :
outputproperty => catches stdout
errorproperty => catches stderr
resultproperty => catches returncode
see Ant Manual for exec task
So for your purpose :
use outputproperty to catch the
version written to stdout
grep the versionstring from
outputproperty via String replace
function from Ant Plugin Flaka
<project xmlns:fl="antlib:it.haefelinger.flaka">
<exec executable="bash" outputproperty="bashversion">
<arg value="--version"/>
</exec>
<fl:let>bashversion ::= '#{replace('${bashversion}','$2','(?s)(.+)(\d\.\d\.\d\(.\)?)(.+)')}'</fl:let>
<fl:echo>
Bashversion => ${bashversion}
</fl:echo>
</project>
output :
[fl:echo] Bashversion => 4.1.7(1)