VI find and replace

Introduction: This tutorial is meant for VI text editor, mainly for linux, generally used in Console [my black Screen]

Tutorial Reference:
Linux.ie

Search (Wraped around at end of file):
  Search STRING forward :   / STRING.
  Search STRING backward:   ? STRING.
  Repeat search:   n
  Repeat search in opposite direction:  N  (SHIFT-n)

Find and Replace
First occurrence on current line: :s/OLD/NEW
Globally (all) on current line: :s/OLD/NEW/g

How did this happen?

Actually IPs changed from 203.91.136.234 to 116.90.239.10.
I had access to only vi editor and then, I need to replace the former with the latter. Later I found this :

:s/203.91.136.234/116.90.239.10/g

This just replaced 203.91.136.234 to 116.90.239.10 and the operator g was meant for global, same as in Perl.

Doing this, that is invoking the command in vi command prompt solved all my problem. But every time I had to press " n " for finding 203.91.136.234. Then invoking :s/203.91.136.234/116.90.239.10/g this solved them.