Which user interface command is utilized to display or manipulate routing information?

The command used to display or manipulate routing information is "ip route." This is part of the iproute2 package, which provides more advanced networking capabilities in Linux compared to the older route command. The "ip route" command can be used to view the current routing table, add, change, or delete routes, and manipulate routing policy rules for a system.

This command allows you to perform operations like checking what routes are currently available on a system, diagnosing routing issues, and modifying routing configurations dynamically, which is crucial for network management and troubleshooting in Linux environments.

By contrast, the other options serve different purposes. The "route show" command is related but is part of the older routing utilities and primarily provides information without the enhanced contextual capabilities of "ip route." The "ip link" command is focused on displaying or manipulating network interfaces, and "ip addr" is used for addressing information rather than routing. Hence, "ip route" is the appropriate choice for managing routing information specifically.