Search & Replace

C-s Incremental search forward
C-r Incremental search backward
C-M-s Regexp search forward
C-M-r Regexp search backward
M-% Search and replace
M-x query-replace-regexp Search and replace with regexps
C-g Abort a search
C-w During a search, highlight the word around the cursor
Up, down arrow keys or M-p, M-n Access search string history