Emacs

http://www.shortcutworld.com/en/linux/Emacs_23.2.1.html

Command	Description
C-x b	Switch buffer.
C-/	Undo.
C-s	Search forward.
C-r	Search backward.
M-x rgrep	Search in files.
C-v	PageDown.
M-v	PageUp.
Shift-→	Move point from window to window using Shift and the arrow keys (like C-x o), see WindMove.
C-x h	Select entire buffer
C-w	Cut
M-w	Copy
C-y	Paste
C-x s	Save
M-b	Back one word
M-f	Foward one word
C-a	Beginning of line
C-e	End of line
C-n	Next line
C-p	Previous line
M-<	Beginning of buffer
M->	End of buffer
C-x C-f	Find file
C-x b	Switch buffer
C-x k	Kill buffer
C-x 2	Split-window-vertically
C-x 3	Split-window-horizontally
C-x o	Switch window
C-x 0	Kill this window
C-x 1	Kill all other windows
M-;	Insert or realign comment on current line; if the region is active, comment or uncomment the region instead
C-M-\	M-x indent-region
C-/	Undo

Cider

Command	Description
C-c M-n	Switch the namespace of the REPL buffer to the namespace of the current buffer.
C-c C-e	Evaluate the form preceding point and display the result in the echo area. If invoked with a prefix argument, insert the result into the current buffer.
C-c M-o	Clear the entire REPL buffer, leaving only a prompt.
C-c C-k	Load (eval) the current buffer.
C-c ,	Run tests for namespace.

Projectile

Command	Description
C-c p f	Display a list of all files in the project. With a prefix argument it will clear the cache first.
C-c p d	Display a list of all directories in the project. With a prefix argument it will clear the cache first.
C-c p s g	Run grep on the files in the project.

expand-region

Command	Description
C-=	Increases the selected region by semantic units. Just keep pressing the key until it selects what you want.

multiple-cursors

Command	Description
C->	Add multiple cursors forward.
C-<	Add multiple cursors backward.
C-c C-<	Marks all parts of the buffer that matches the current region.