Emacs

Minibuffer

C-x ^   make it taller in the normal fashion
completion commands in minibuffer TAB/SPC/RET/?
?                (minibuffer-list-completions)
TAB              (minibuffer-complete).
SPC              (minibuffer-complete-word)
RET              (minibuffer-complete-and-exit)


Minibuffer History
up               (previous-history-element)
down             (next-history-element)
M-r regexp RET   (previous-matching-history-element)
M-s regexp RET   (next-matching-history-element)


Repeating Minibuffer Commands
C-x ESC ESC      (repeat-complex-command)
M-x list-command-history Display the entire command history

http://snebulos.mit.edu/htdocs/emacs.html 

http://www.gnu.org/software/emacs/manual/html_node/emacs/index.html#Top