lsof flags & options

-i

List open network connections, optionally filtered by port or protocol.

lsof -i

lsof -i :8080

lsof -i tcp

-p

Show files opened by a specific process ID.

lsof -p 1234

-u

Show files opened by a specific user.

lsof -u www-data

lsof -u ^root

-c

Show files opened by processes matching a command name.

lsof -c nginx

lsof -c python

+D

Recursively list all open files under a directory.

lsof +D /var/log

-t

Output only process IDs (useful for piping).

lsof -t -i :3000

kill -9 $(lsof -t -i :3000)

-n

Don't resolve IP addresses to hostnames.

lsof -n -i :443

-i4, -i6

Show only IPv4 or IPv6 connections.

lsof -i4

lsof -i6