vi is a great editor and I just want to say it out loud!
Learn to use it, learn to love it and then learn to enjoy it...
I constantly find myself typing ESC h,j,k,l don't you?
PS learn to use hjkl and not the arrows, it will help you when you get your shell to vi mode (set -o vi)
Learn the tricks, learn search/replace and other tools and you'll greatly enhance your job performance...
I currently have to edit a lot of SQL files and search/replace just saved me 4-5 days of typing (and who knows how many mistakes)...
a simple ESC
:% s/what am I changing/what the new text will be/g
is all it takes... (g is for global, so if you have more occurencies of the same text all will be changed)
good options to know are
which will only run from 4th to 8th line and ask you to approve every change
other regexp formats are also supported:
:% s/this line has \(first\) argument/here was the \1 argument/g
just to make sure you know which lines to include try: