But if the underlying operating system is the same, you can just copy the installation.
For example, in Linux, assuming that $SPLUNK_HOME is /opt/splunk' and you are running as the usersplunkIT`
# on the current machine
tar -czf splunk.tgz splunk
# on the new machine (assumes that user splunkIT exists there as well)
# copy the splunk.tgz to /opt using any method, and
# make sure that splunk.tgz is owned by splunkIT
tar -xzf splunk.tgz
Note that this assumes that the Splunk indexes are also stored beneath the /opt/splunk directory. If they are not, you will have go through similar steps to copy them as well.