Technical
Commands

Find and Replace

First occurrence on current line:      :%s/OLD/NEW
Globally (all) on current line:        :%s/OLD/NEW/g 
Between two lines #,#:                 :#,#s/OLD/NEW/g
Every occurrence in file:              :%s/OLD/NEW/g 

Useful set options ( ruby editing )

syntax on
set autoindent
set wrapmargin=1
set formatexpr=1
set tabstop=2
set shiftwidth=2
set smartcase   " Do case insensitive matching
au BufNewFile,BufRead *.yaml,*.yml so ~/.vim/plugin/yaml.vim