EmacsWiki: Emacs Key Notation (original) (raw)
This page is about the notation of key sequences in Emacs documentation and in Emacs itself (GUI, terminal-mode).
Overview
C-
means (press and hold) the Control key
M-
means the Meta key (the Alt key, on most keyboards)
S-
means the Shift key (e.g. ‘S-TAB’ means Shift Tab)
DEL
means the Backspace key (not the Delete key)
RET
means the Return or Enter key
SPC
means the Space bar
ESC
means the Escape key
TAB
means the Tab key
A notation such as ‘C-M-x’ (or, equivalently, ‘M-C-x’) means press and hold both Control and Meta (Alt) keys while hitting the ‘x’ key.
See the section “Kinds of User Input” in the EmacsManual (User Input).
Angle-Bracket Notation
Some keys are referred to as “function” keys or “pseudo” keys. This includes keys that are not among the keyboard function keys ‘F1’,…‘F12’. It includes keys that might not be on your keyboard, but are on other keyboards. It even includes keys, such as ` <insert-file>’, that are not on any keyboard, anywhere. For one thing, Emacs treats menu bindings as key bindings: a menu item is implemented as a pseudo key.
Starting with release 21, the GnuEmacs maintainers decided to denote such keys by enclosing their names in angle brackets: <...>. Examples: ` <delete>’ is the Delete key, ` <insert>’ is the Insert key, and ` <tab>’ is the Tab key (or rather it is sometimes, depending on your keyboard).
Modifier keys that are part of a key sequence that contains a pseudo key are sometimes written inside the angle brackets: ` <S-tab>’, ` <C-insert>’. And sometimes they are written outside: ` S-<tab>’, ` C-<insert>’.
Are angle brackets really necessary, in order to disambiguate keys?
No. If you would like to do without the angle brackets, at least in most interactive contexts (i.e., not hard-coded, literal occurrences), you can do so. Just use library NaKeD (No Angles Key Descriptions).