How to retrieve first line from a string property in Ant?

Question

I have a property which generates with lines of string. I'm trying to retrieve/store the first line only instead of all the lines.

I was trying to do something like this but it prints all the lines:

<for param="line" list="${targetDeviceUDID}" delimiter="${line.separator}">
    <sequential >
    <echo>@{line}</echo>
    </sequential>
</for>

Answer 1

You can use Ant's filterchain ability with the headfilter to accomplish this.

<project name="build" default="echo-first-line">
    <target name="echo-first-line">
        <property name="input" value="abc${line.separator}def${line.separator}123${line.separator}456" />

        <echo message="Input:${line.separator}${input}" />

        <echo message="${line.separator}" />

        <loadresource property="output">
            <propertyresource name="input" />
            <filterchain>
                <headfilter lines="1" />
            </filterchain>
        </loadresource>
 
        <echo message="Output:${line.separator}${output}" />
   </target>
</project>