How to display the output of the exec-maven-plugin instantaneously

Question

I'm using Maven 3.1.1 and the exec-maven-plugin (1.3) in order to execute a bash script during a build job.

The bash script produces output on stdout with echo and printf. I've noticed that the output of the script is not written to the maven console output instantaneously. Instead the maven console output "freezes" until it gets updated with multiple output lines of the bash script at once. I don't know what's the trigger for an update of the maven output (timeout? full output buffer?) but it's very slow.

Let's take a very simple bash script, e.g. counter.sh:

#!/usr/bin/env bash
for i in `seq 1 1000`; do
  echo $i
  sleep 0.5
done 

And here's my plugin configuration in the pom.xml:

<plugin>
    <artifactId>exec-maven-plugin</artifactId>
    <groupId>org.codehaus.mojo</groupId>
    <version>1.3</version>
    <executions>
        <execution>
            <id>execute-script</id>
            <phase>package</phase>
            <goals>
                <goal>exec</goal>
            </goals>
            <configuration>
                <executable>${project.build.directory}/executable/counter.sh</executable>
            </configuration>
        </execution>
    </executions>
</plugin>

When I execute the build job with mvn clean package, the maven output freezes at the exec-maven-plugin and shows no progress/output until the script has completed after ~8 minutes.

When I execute another script that is running even longer, I get a block of output each ~15 minutes.

What I'm looking for is a way to see the output of the bash script instantaneously in the maven console output.

Update: Solution using maven-antrun-plugin (thanks to Ivan)

<plugin>
    <artifactId>maven-antrun-plugin</artifactId>
    <version>1.7</version>
    <executions>
        <execution>
            <id>execute-script</id>
            <phase>package</phase>
            <goals>
                <goal>run</goal>
            </goals>
            <configuration>
                <target>
                    <exec dir="${project.basedir}" executable="${project.build.directory}/executable/counter.sh" />
                </target>
            </configuration>
        </execution>
    </executions>
</plugin>

Answer 1

JFYI, the issue is fixed in exec-maven-plugin v 1.3.2 - http://blog.soebes.de/blog/2014/07/28/mojo-exec-maven-plugin-version-1-dot-3-2-released/