Case sensitive Find and Replace

vim find and replace is doen with %s

the trailing /g is global so if there are 2 instances on a single line it will replace both

the trailing /I is case insensitive

the trailing /c is to coose

this will match all occurences of Old with New %s/Old/New/gI

this will match all occurrences of old, Old, OLD with new %s/old/new/g

this will match all occurrences of old, Old, OLD with new and then let you choose which ones to replace %s/old/new/gc