Cheat Sheet

Emacs comes with a lot of key combinations preconfigured. Some are so frequently used that they become second nature, some are so infrequently used that you are better off finding the name of the command when you need it. This list contains the ones that are in my grey zone - useful key combinations that aren't second nature yet.

Buffers

These key combinations are useful for switching between and generally working with buffers in Emacs.
Key combination	Function	Description
C-xb	switch-to-buffer	Type the name of a buffer to display in the current window. If no buffer with the typed name exists, one will be created, which is not linked to a file.
C-xC-b	list-buffers	Display a list of existing buffers in a new window, leaving the focus in the current window.
C-xk	kill-buffer	Kill the current buffer, but do not harm the window itself. If the buffer is modified, and linked to a file, prompt for saving.
C-xC-right	next-buffer	Display the next buffer in the current window, in the order they appear in the buffer-list (use C-xC-b to display the buffer-list).
C-xC-left	previous-buffer	Display the previous buffer in the current window, in the order they appear in the buffer-list (use C-xC-b to display the buffer-list).

Region: Select, Cut / Copy, and Paste

How to work with regions, the mark, and how to do cut, copy and paste in Emacs.
Key combination	Function	Description
C-space	set-mark-command	Selecting text in Emacs works by first setting the mark at one end of the desired selection, and then moving point to the other end.
C-xh	mark-whole-buffer	Set the mark at the end of the buffer and move point to the beginning of the buffer, making the current region the whole buffer ("Select All" in other applications).
C-xC-x	exchange-point-and-mark-nomark	Swap point and mark, without making the mark active (Use exchange-point-and-mark to also activate the mark).
C-M-\	indent-region	Indent the current region - this does something intelligent depending on the current major-mode.
C-w	kill-region	Delete the current region and put it in the kill ring ("Cut" in other applications).
C-y	yank	Insert the most recently killed text from the kill ring at point ("Paste" in other applications). Use yank-pop to cycle through the kill ring (no equivalent in most other applications).
M-y	yank-pop	Only allowed immediately following a yank or yank-pop- cycles through the kill ring, inserting each entry in the kill ring at point. Only one entry from the kill ring will be inserted at point.

Text editing

How to efficiently edit text in Emacs.
Key combination	Function	Description
M-%	query-replace	Replace one string by another, prompting the user for every match. Tries to preserve case for each match.
M-q	fill-paragraph	Format point paragraph nicely - does a good job of detecting paragraph boundaries, very useful for breaking up long lines.
M-space	just-one-space	Delete all whitespace around point, replacing it by ARG spaces (default is 1).
M-d	kill-word	Delete the ARG words following the point (default is 1).
C-backspace	backward-kill-word	Delete the ARG words preceding the point (default is 1).
C-k	kill-line	Delete from point to the end of the line.

Meta-commands

Sometimes, you execute a command, then realise that was not what you wanted. These commands help you stop or undo commands.
Key combination	Function	Description
C-g	keyboard-quit	Make Emacs stop doing whatever it is doing: If a keyboard macro is in the process of being defined, abort it. If a command is running, make it quit. If a command is waiting for input from the user (e.g. after asking a question in the mini-buffer, abort the command and return the focus to the buffer in which the command was issued. If Emacs is not doing anything, just beep.
C-_ C-/ ( C-xu)	undo	Undo the previous command. Pass a numeric argument (e.g. C-u4C-_) to undo the latest e.g. 4 changes.
C-u <number> <command>		Invoke <command>, passing it <number> as an argument.
M-<number> <command>		Invoke <command> number times.
C-hl	view-lossage	Display the previous 100 typed characters - useful in combination with undo.
C-x(	kmacro-start-macro	Begin defining a keyboard macro - subsequent keyboard input is executed and recorded, and can be executed again. Use C-g to abort the macro definition.
C-x)	kmacro-end-macro	End defining a keyboard macro.
C-xe	kmacro-end-and-call-macro	Invoke the most recently defined macro. If a macro is being defined, consider it done and execute it. Subsequently pressing "e" executes the macro again. Pass 0 as an argument to keep executing it until there is an error.
C-u C-uC-u C-[0-9] M-[0-9] C-M-[0-9]	universal-argument universal-argument digit-argument digit-argument digit-argument	Pass a numeric argument to the next command (although a preceding C-u means something else to some commands, see C-hkC-u): Pass a numeric argument to the next command (default is 4): C-u42C-xe invokes the most recently defined macro 42 times. Each successive C-u multiplies the default argument by 4, so C-uC-u is 16, C-uC-uC-u is 64, etc. Handy for passing numeric arguments to C- shortcuts, e.g. C-5C-xe. Repeat to pass multi-digit arguments, e.g. C-4C-2C-xe executes the macro 42 times. Handy for passing numeric arguments to M- shortcuts. Handy for passing numeric arguments to M-C- shortcuts.

Windows

When you have many buffers open in Emacs, it becomes important to efficiently work with the windows you edit them in.
Key combination	Function	Description
C-x0	delete-window	Close the current window (use C-x40 / kill-buffer-and-window to also kill the current buffer).
C-x1 EscEscEsc	delete-other-windows	Make the current window fill the entire current frame.
C-x2	split-window-vertically	Split the current window into two windows, one on top of the other, each occupying half the space.
C-x3	split-window-horizontally	Split the current window into two windows, one next to the other, each occupying half the space.
C-x+	balance-windows	Split the available space in the current frame evenly among the displayed windows.
C-x^	enlarge-window	Make the current window ARG lines higher (use shrink-window to make it ARG lines lower).
C-x}	enlarge-window-horizontally	Make the current window ARG columns wider (use shrink-window-horizontally to make it ARG columns narrower).

By default, only the functions which enlarge the active window have shortcuts. To shrink a window, either enlarge another window, or pass a negative ARG to an enlarging function. See Window Resize for more info.

The larger a buffer is, the more important it is to efficiently move the point and find the place you want.
Key combination	Function	Description
M-< C-home	beginning-of-buffer	Move point to the top of the buffer. With argument, go to ARG*10 percent position in the file (from the top).
M-> C-end	end-of-buffer	Move point to the bottom of the buffer. With argument, go to 100-ARG*10 percent position in the file (from the top).
C-a	move-beginning-of-line	Move point to the beginning of the line.
C-e	move-end-of-line	Move point to the end of the line.
M-gM-g	goto-line	Go to line number ARG. Prompt for a line number if no argument is given. If point is on a number, that number is the default for the prompt.
C-l	recenter	Redraw the screen, and move the visible area of the current buffer so that point is in the middle of the current window.
C-v / M-v	scroll-up	Display the next / previous screen of data from the buffer in the current window.
C-left / M-left	backward-word	Move point to the first character of the word it is on. If point is already on the first character, move it to the first character of the preceding word.
C-right / M-right	forward-word	Move point to the first character after the word it is on. If point is already on the first character after a word, move it to the first character after the next word.
C-up	backward-paragraph	Move point to the first character of the paragraph it is on. If point is already on the first character, move it to the first character of the preceding paragraph.
C-down	forward-paragraph	Move point to the first character after the paragraph it is on. If point is already on the first character after a paragraph, move it to the first character after the next paragraph.

Bookmarks

For more details, see the GNU docs:

TODO.
Key combination	Function	Description
C-x r l	list-bookmarks	List bookmarks. Also good for annotating and editing bookmarks - see C-x h m for more details.
C-x r m C-x r m name	bookmark-set	Create a bookmark for the visible file at point. Optionally, the bookmark can be named (default is the file name).
C-x r b name	bookmark-jump	Jump to the bookmark.
M-x bookmark-delete	bookmark-delete	Delete a bookmark (prompts for the bookmark name).
M-x bookmark-save	bookmark-save	Save the current bookmarks to a file. Bookmarks are saved in ~/.emacs.d/bookmarks or ~/.emacs.bmk as specified by bookmark-default-file. If bookmark-save-flag is set to 1, bookmarks will be saved every time they change. See also .emacs.