Emacs
Overview
The features of GNU Emacs include:
- Content-sensitive editing modes, including syntax coloring, for a wide variety of file types including plain text; source code (for pretty much any programming/scripting language you can imagine); LaTeX.
- Complete built-in documentation, including a tutorial for new users.
- Support for many languages and their scripts, including all the European “Latin” scripts, Russian, Greek, Japanese, Chinese, Korean, Thai, Vietnamese, Lao, Ethiopian, and some Indian scripts.
- Highly customizable, using Emacs Lisp code or a graphical customization interface.
- Games such as Tetris, Snake, etc.
- Spell checking as you type or when required (can also just check spelling of comments when in programming modes) with ability to add words.
- A large number of extensions that add other functionality, including a project planner, mail and news reader, calculator (simple or programmable), PDF viewer, web browser, debugger interface, calendar, twitter client and more. Many of these extensions are distributed with GNU Emacs; others are available separately.
Commands
After learning a few basic keystroke commands, you can become a lot more productive in Emacs.
When typing a command you can use [TAB] completion, which will complete the command name for you or list the possible commands.
Guide to keys
C-x = (hold [CONTROL], press x, then release [CONTROL])
C-x C-s = (hold [CONTROL], press x, then press s, then release [CONTROL])
M-2 = (hold [ALT], press 2, then release [ALT])
[note M = META usually [ALT] or [ESCAPE] when using [ESCAPE] as META release it before pressing the next key (i.e. M-2 = press and release [ESCAPE] then press 2)].
Written commands
Sometimes the required action doesn't have an associated key-sequence, in these cases the written command must be used (M-x is pressed followed by the command):
ispell-buffer = (hold [ALT], press x, release [ALT], then type "ispell-buffer" in the mini buffer)
Lookup table
The following is a lookup table of basic commands. Emacs has so many commands it would be impossible to list them all, but hopefully this will be enough to get you started.
| Action | Key-sequence | Command |
|---|---|---|
| Open file | C-x C-f | find-file |
| Close | C-x C-c | save-buffers-kill-emacs |
| Save file | C-x C-s | save-buffer |
| Save as | C-x C-w | write-file |
| Page down | C-v | scroll-up |
| Page up | M-v | scroll-down |
| Goto top | M-< | beginning-of-buffer |
| Goto end | M-> | end-of-buffer |
| Goto line | M-g g | goto-line |
| Goto start of line | C-a | beginning-of-line |
| Goto end of line | C-e | end-of-line |
| Search forwards | C-s search term | isearch-forward search term |
| Repeat last search forwards | C-s C-s | isearch-repeat-forward |
| Search backwards | C-r search term | isearch-backward search term |
| Repeat last search backwards | C-r C-r | isearch-repeat-backward |
| Cancel command | C-g | keyboard-quit |
| Kill line | C-k | kill-line |
| Kill sentence | M-k | kill-sentence |
| Yank last kill | C-y | yank |
| Yank previous kill | M-y | yank-pop |
| Split window horizontally | C-x 2 | |
| Split window vertically | C-x 3 | |
| Swap active window | C-x o | |
| Merge windows | C-x 1 | |
| List buffers | C-x C-b | list-buffers |
| Switch to buffer | C-x b | switch-to-buffer |
| Switch active buffer left | C-x [LEFT] | previous-buffer |
| Switch active buffer right | C-x [RIGHT] | next-buffer |
| Kill Buffer | C-x k | kill-buffer |
| Spell-check current buffer | none | ispell-buffer |
| Spell-check current word | none | ispell-word |
| Indent code | C-M-\ | indent-region |
| Goto matching closing bracket | C-M-f | |
| Goto matching opening bracket | C-M-b | |
| Comment a region | M-; | comment-or-uncomment-region |
Performing other tasks
Reading
Rmail
The simplest (to set up) E-mail client in Emacs, is Rmail, to invoke Rmail press:
M-x rmail
To use Rmail for reading E-mail, other than system mail, you will have to use a program to fetch your E-mail from the server, such as fetchmail or offlineimap.
Gnus
Another option is Gnus, which is primarily a newsreader, but can also be used for reading E-mail, and can be configured to get your E-mails from the server without the aforementioned mail fetching programs, but will take a little more setting up than Rmail.
Sending
Mail can send your E-mail, which is invoked with:
M-x mail
You can also specify your: E-mail address, name, signature, etc in your ~/.emacs file, so that it is already filled in when you start composing an E-mail.
Newsreader
Gnus
Gnus is an outstanding newsreader and can be started by pressing:
M-x gnus
To use Gnus, you will first have to setup your ~/.gnus.el file, a brief guide to Gnus is available at: Gnus
IRC client
ERC is an Emacs IRC client which can be started with:
M-x erc
You must first add the following to your ~/.emacs file:
(require 'erc)
Getting Started
When you start ERC, you will be asked for some information:
IRC server:
irc.freenode.net
IRC port:
6667
Nickname:
your nickname
Password:
your password (optional)
The commands for ERC are just standard IRC commands.
Troubleshooting
Attempts to install or refresh packages from GNU ELPA results in 'failed to download gnu archive'.
The GNU ELPA repository is the default repository GNU Emacs pulls from. The GPG keys used by this repository were changed in September, 2019. As such, versions of Emacs released before Sep. 2019 face the issue of not being able to install packages from the repository due to signature verification errors.
This issue may be encountered by users of openSUSE Leap 15.2, as the version available in the repository is Emacs 25.3.1. Emacs 25.3 was released in 2017.
The most convenient solution for users experiencing this issue would be to download the gnu-elpa-keyring-update package from the website, which, when installed, would update the GPG keys stored by your installation of emacs, and allow you to access the packages again.
Simply download the tar file from the website, and run the command
M-x package-install-file
After pressing enter, Emacs will prompt you for the location of the downloaded package.
This method can also be used as a workaround if you wish to install some packages but haven't updated the GPG keys of your installation.