This is a small note for my personal needs. Maybe it will be helpful also to other people.

Displaying interface configuration:

root@ifconfig

Network interface configuration edit:

root@sudo vi /etc/network/interfaces

– vi editing commands:
 i – inserting text in the configuration (from my point of view it is editing) – to end editing “Esc”
 :w – save your configuration
:q – quit if you havent made any changes

– after the changes has been made in interface configuration a restart of networking services is needed

root@sudo /etc/init.d/networking restart

 A very good link:

http://www.washington.edu/computing/unix/vi.html