Code
vim
/foo " search forward for 'foo'
?foo " search backward
n / N " next / previous match
* / # " search word under cursor forward / backward
:set ignorecase " case-insensitive search
:set smartcase " case-sensitive when pattern has uppercase
" Substitute: :[range]s/pattern/replacement/flags
:s/old/new/ " replace first match on current line
:s/old/new/g " replace all on current line
:%s/old/new/g " replace in whole file
:%s/old/new/gc " confirm each replacement
:5,20s/foo/bar/g " replace in lines 5-20
:%s/\<word\>/TERM/g " match whole words only
:%s/\(foo\)\(bar\)/\2\1/g " swap groups using backrefs
" Magic: very-magic mode with \v reduces escaping
:%s/\v(\d+)/number \1/g