Setting environment variable with maven 2.x

This answer is not correct, at least not completely (see comments).
Unfortunately I can't delete it as it has been accepted. Your milage may vary.

Use the exec:exec mojo.

  <plugin>    <groupId>org.codehaus.mojo</groupId>    <artifactId>exec-maven-plugin</artifactId>    <version>1.1</version>    <executions>      <execution>        <id>exportVar</id>        <phase>initialize</phase>        <goals>          <goal>exec</goal>        </goals>      </execution>    </executions>    <configuration>      <executable>export</executable>      <arguments>        <argument>GGA_FRE=${my.path}</argument>      </arguments>    </configuration>  </plugin>

now call it like this mvn install -Dmy.path=/var/users/groucho

I don't think there is a Java way to set environment variable the way export command does (so that it is avaliable outside of Java). (see for example this question: How do I set environment variables from Java?)

However, you might hack you way around: for example use maven-exec plugin to run a shell script and then set the variable in the script. You might pass a parameter to your script to specify the variable value.(note that I have not tested this)