Emacs : The One True Editor

From the Jargon File:

EMACS: /ee'maks/ n. [from Editing MACroS] The ne plus ultra of hacker editors, a programmable text editor with an entire LISP system inside it. . . .

To get started, go to the course web page and read the tutorials. Here's a quick conceptual overview:

• The cursor is a rectangular block and is referred to as the point.
• The modeline displays information about the buffer displayed in the current window. A buffer is a logical "thing" that you are working on. When you open a file, it will be loaded into a buffer, typically with the same name as the file.
• Every buffer is edited in a mode. The most basic mode is Fundamental, which provides only the most basic Emacs editing features. There are modes for many different languages.
• There are many "special" buffers that do not correspond to loaded files. The one above is called *scratch*. This buffer runs in Lisp Interaction mode, which means that you can interactively type and evaluate Lisp expressions (try typing "(+ 1 1)" followed by Control-J while in *scratch*).