Section 8.1. Emacs Concepts

8.1. Emacs Concepts

This section describes some Emacs terminology that may be unfamiliar if you haven't used Emacs before.

8.1.1. Modes

One of the features that makes Emacs popular is its editing modes . The modes set up an environment designed for the type of editing you are doing, with features such as having appropriate key bindings available and automatically indenting according to standard conventions for that type of document. There are two types of modesmajor and minor. The major modes include modes for various programming languages such as C or Perl, for text processing (e.g., SGML or even straight text), and many more. One particularly useful major mode is Dired (Directory Editor), which has commands that let you manage directories. Minor modes set or unset features that are independent of the major mode, such as auto-fill (which controls word wrapping), insert versus overwrite, and auto-save. For a full discussion of modes, see Learning GNU Emacs or the Emacs Info documentation system (C-h i).

8.1.2. Buffer and Window

When you open a file in Emacs, the file is put into a buffer so you can edit it. If you open another file, that file goes into another buffer. The view of the buffer contents that you have at any point in time is called a window . For a small file, the window might show the entire file; for a large file, it shows only a portion of a file. Emacs allows multiple windows to be open at the same time to display the contents of different buffers or different portions of a single buffer.

8.1.3. Point and Mark

When you are editing in Emacs, the position of the cursor is known as point . You can set a mark at another place in the text to operate on the region between point and mark . This is useful for deleting or moving an area of text.

8.1.4. Kill and Yank

Emacs uses the terms kill and yank for the concepts more commonly known today as cut and paste. You cut text in Emacs by killing it, and paste it by yanking it back. If you do multiple kills in a row, you can yank them back all at once.