list of open files in current directory:-
$ lsof +D .
list files open by a specific user:-
$ lsof -u username
list of all open files by specific process:-
$ lsof -p PID
kill all process belongs to as particular process:-
$ kill -9 `lsof -t -u username`
list of all tcp udp connection
$ lsof -i :port
$ lsof -i tcp ; lsof 0i udp;
list all network file system (NFS):-
$ lsof -N -u username -a
