# netstat -tunapo

-t : tcp
-u : udp
-n : don’t resolve names
-a : display all sockets
-p : display PID/Program name for sockets
-o : display timers

# netstat -nr

-n : don’t resolve names
-r : display routing table

# netstat -ni | column -t

-n : don’t resolve names
-i : display interface table

# netstat -npl

-l : show only listening sockets.

# netstat -nCc

-C : show routing info from the route cache.
-c : continuous listing