How do I configure my router to prefer an Open Shortest Path First (OSPF) route over an EIGRP route when the route is learned from both sources?

The short answer is to use the distancecommand under the routing process. OSPF has a default administrative distance of 110 and EIGRP has a default administrative distance of 90 for internal routes. If the same route prefixes are learned under both routing protocols, EIGRP-learned routes will be installed into the IP routing table because of the lower administrative distance (90 is less than 110). The key to having OSPF routes installed in the Routing Information Base (RIB), instead of EIGRP routes, is to make the administrative distance of OSPF less than that of EIGRP that uses the distance ospfcommand. To learn more about administrative distance, refer to What Is Administrative Distance?