The following steps are similar to joining a cluster node using the GUI. That means the data is copied over the network, and the search index is re-created (which may take some time):
java -Xmx512m -jar crx-quickstart-2.2.*.jar -unpack
cp <master>/crx-quickstart/repository/repository.xml <slave>/crx-quickstart/repository/
cp <master>/crx-quickstart/repository/cluster.properties <slave>crx-quickstart/repository/
echo "addresses=x.x.x.x" >> crx-quickstart/repository/cluster.properties
where x.x.x.x is replaced by the correct address. At the master, the IP address of the slave should be added to the cluster.properties file as well.
cp <master>/repository/repository/namespaces <slave> /crx-quickstart/repository/repository/