3.2. Control and Meta¶

Throughout this chapter, we will use C- to refer to the control key (CTRL) and M- to refer to the meta key. On most systems, ALT or ESC correspond to M-. On macOS, the Terminal application can be configured to use OPT (option) key as M-. If you are using macOS and have not setup OPT to work as meta, then follow the instructions here.

Modifier Key	Name	Usually
`C-`	Control	`CTRL`
`M-`	Meta	`ESC`, `ALT`, or `OPT`

Emacs commands are recognized by their key bindings, which is just a fancy way of saying keyboard shortcuts. To use Emacs commands effectively, you need to understand how to read their associated key bindings so that you can successfully make the appropriate keystrokes. In the table below, we’ll use KEY(key) to denote that you should press key while holding KEY and (key) to denote that key should be pressed without any kind of modifier key. For example, CTRL(x, f) means to hold CTRL, press x, then press f, then release CTRL. An alternative would be CTRL(h), (t) which means to hold CTRL, press h, release CTRL, then press t.

Command	Binding	Alternative	Keystrokes
Open/Find File	`C-x C-f`	`C-xf`	`CTRL(x, f)`
Emacs tutorial	`C-h t`		`CTRL(h), (t)`

If a binding has consecutive occurrences of either the C- or M- modifier keys, then there is no need to release the modifier key between those occurrences. This can be seen in the first example, where both of the following keystroke sequences result in C-x C-f:

CTRL(x), CTRL(f)
CTRL(x, f)