Which netstat parameter displays the active TCP connections and retrieves the process ID for each connection?

The parameter that displays active TCP connections and retrieves the process ID for each connection is indeed the one that includes the flag '-o'. This parameter, when used with the netstat command, provides a comprehensive view of the network connections in use on a system, including the process ID (PID) associated with each connection. This ability is crucial for identifying which applications or processes are utilizing specific network resources, aiding in troubleshooting network-related issues, security assessments, and understanding how programs communicate over the network.

The other parameters serve different purposes: -A displays all connections and listening ports, but does not include the PID; -r shows the routing table, which is not directly related to active connections; -s provides statistics for protocol usage, which can give an overview of data flow but lacks the specifics of individual connections or their associated processes. Thus, understanding the role of each parameter in netstat is essential for effective network monitoring and management.