lsof:tldr:ceae6

The command lsof is used to list open files and the files that are being used by active processes in a Unix-like operating system.

Here is the breakdown of the command:

lsof: is the command itself, used to list open files.

-i6TCP:${port}: specifies the internet address and port number, where ${port} should be replaced with the specific port number you want to check. The -i flag is used to filter internet addresses and protocols, and 6 denotes IPv6. The TCP protocol means it will filter for TCP connections only.

-sTCP:LISTEN: filters the output to only show the processes that are listening for connections. The TCP:LISTEN parameter means that it will only display the processes in a listening state for TCP connections.

-n: disables the translation of IP addresses to hostnames. This prevents the command from performing reverse DNS lookups and speeds up the execution.

-P: disables the translation of port numbers to service names. Similar to -n, this flag prevents the command from performing port-to-service name lookups.

In summary, this command will list all the open files associated with a specific IPv6 TCP port that is currently in a listening state. The -n and -P options are used to speed up the execution by avoiding unnecessary DNS and service name lookups.