Add warning on netstat: netstat is deprecated and add the new command.

cheatsheets/netstat

@@ -1,3 +1,5 @@
+# WARNING ! netstat is deprecated. Look below.
+
 # To view which users/processes are listening to which ports:
 sudo netstat -lnptu
 
@@ -11,3 +13,16 @@ Example output: 1507/python
 
 # Fast display of ipv4 tcp listening programs
 sudo netstat -vtlnp --listening -4
+
+# WARNING ! netstat is deprecated.
+# Replace it by:
+ss
+
+# For netstat-r
+ip route
+
+# For netstat -i
+ip -s link
+
+# For netstat-g
+ip maddr