A possible approach would be from Ant+Groovy:
First create a build.xml file with the following content:
<?xml version="1.0" encoding="UTF-8"?>
<project name="project" default="default">
<taskdef name="groovy"
classname="org.codehaus.groovy.ant.Groovy"
classpath="/home/me/workspace/Groovy/lib/groovy-all-2.1.4.jar" />
<target name="default">
<groovy>
bundle = org.eclipse.core.runtime.Platform.getBundle("org.eclipse.core.resources");
resPlugin = bundle.loadClass("org.eclipse.core.resources.ResourcesPlugin");
root = resPlugin.getWorkspace().getRoot();
project = root.getProject("new");
project.create(null);
project.open(null);
resPlugin.getWorkspace().save(true, null);
</groovy>
</target>
</project>
Then run by executing:
./eclipse -nosplash -data /home/me/workspace -application org.eclipse.ant.core.antRunner -buildfile /home/me/build.xml
Of course, a full-fledged script will contain some more code, perhaps run using an IWorkspaceRunnable and so on but the basics is here. Just be sure that any classes that you want to use from Eclipse are located using the Platform.getBundle + bundle.loadClass mechanism.