What command is used to display which ports the processes use on Linux systems?

The command that is most commonly used to display which ports the processes are using on Linux systems is the ss command. This tool is more modern and efficient than netstat, providing detailed information about socket connections and their status. It can show TCP, UDP, and other protocol connections, along with their respective processes that own those connections.

Using ss typically yields faster results since it retrieves information directly from the kernel without requiring the same processing that netstat does. The output can reveal active connections, listening ports, and associated PID (Process ID) of the processes using those ports.

While lsof can also be used to display open files and the corresponding processes, which include network sockets, it has a broader application and doesn’t specifically focus on network connections alone. netstat, another option, is older and could be phased out in favor of ss, though it still provides similar information. The ifconfig command, on the other hand, is primarily used for configuring network interfaces and does not display port usage or process information at all.

Overall, ss is a preferred choice for efficiently displaying which processes are using which ports on a Linux system due to its performance and specificity for socket statistics.