Monday, August 20, 2007

Emacs: the GNU's editor

I have been using Vim editor for past ( almost ) four years, but now I have switched over to Emacs. I find it more intuitive ( just a personal opinion ). While I was learning Emacs I had few queries. So, I have prepared a small HOWTO which might help a new emacs user.

HowTo Colorize the syntax?

M-x font-lock-mode

Here M is the Meta key, which may be Alt or Esc (top-left corner of the keyboard). So the above is equivalent to "Alt+x font-lock-mode" or "Esc x font-lock-mode".

How do I add color themes to my Emacs editor?

Install the following package :


you will get a lot of color themes (for Emacs) installed onto your system. To select / apply a theme use M-x color-theme-select Theme-Name
I liked Hober and Euphoria.

I usually log onto a slow server (say, using SSH) and editing of files on the remote server has become a hated task, usually when I have to navigate a big text/program file up and down. Can Emacs help me?

Sure, Emacs can help you edit files on the remote system. Install the following package:
for emacs and go ahead.

While logging in onto a server for editing files, TRAMPS asks me a password each time I try to open a separate file. So, how do I create ( SSH ) login with no password required?

On remote system (server):
$ ssh-keygen -t rsa

On local system (localhost):
$ ssh-keygen -t rsa
$ cd .ssh
$ scp user@server :~/.ssh/id_rsa.user_at_localhost

On remote system ( server ):
$ cd ~/.ssh
$ cat id_rsa.user_at_localhost >> authorized_keys

Now you login from localhost to server.

How do I recover a file from the last session, which unfortunately crashed?

M-x recover-file

How do I indent a region?


How do I comment a region?


How do I AutoComplete a word which I have typed partially, but it is already present somewhere in the currrent file?


How do I delete all trailing whitespace from lines in the text ( or the selected region) ?

M-x delete-trailing-whitespace RET. (This command does not remove the form-feed characters.)

How do I use the Code Folding feature of Emacs?

To fold all the function bodies: M-1 C-x $ and magic happens!
As usual, it's white magic: C-x $ will bring your code back.

How do I Customize my EMACS using the .emacs configuration file?

This is a file I found somewhere on the Internet. Just copy paste the contents if you want to experiment.

(setq additional-paths '("/home/tuxdna" "/home/joe/misc/lisp"))
(setq load-path (append additional-paths load-path))

(setq font-lock-maximum-decoration t)
(setq visible-bell t)
(setq require-final-newline t)
(setq resize-minibuffer-frame t)
(setq column-number-mode t)
(setq-default transient-mark-mode t)
(setq next-line-add-newlines nil)
(setq blink-matching-paren nil)
(global-font-lock-mode 1 t)
(blink-cursor-mode -1)
(tool-bar-mode -1)
(tooltip-mode -1)

;;Customized syntax highlighting colors
(set-default-font "-misc-fixed-medium-r-normal-*-*-200-*-*-c-*-koi8-r")
(set-foreground-color "#dbdbdb")
(set-background-color "#000000")
(set-cursor-color "#ff0000")
(custom-set-variables '(load-home-init-file t t))

(if (> (display-color-cells) 20)
'(font-lock-builtin-face ((t (:foreground "deepskyblue"))))
'(font-lock-comment-face ((t (:foreground "gray60"))))
'(font-lock-doc-face ((t (:foreground "darkkhaki"))))
'(font-lock-keyword-face ((t (:foreground "magenta"))))
'(font-lock-function-name-face ((t (:foreground "green" :background "seagreen"))))
'(font-lock-string-face ((t (:foreground "gold"))))
'(font-lock-type-face ((t (:foreground "cyan" :background "slateblue"))))
'(font-lock-variable-name-face ((t (:foreground "yellow"))))
'(modeline ((t (:foreground "plum1" :background "navy"))))
'(region ((t (:background "sienna"))))
'(highlight ((t (:foreground "black" :background "darkseagreen2"))))
'(diff-added-face ((t (:foreground "green"))))
'(diff-changed-face ((t (:foreground "yellow"))))
'(diff-header-face ((t (:foreground "cyan"))))
'(diff-hunk-header-face ((t (:foreground "magenta"))))
'(diff-removed-face ((t (:foreground "red")))))


(setq suggest-key-bindings t)
(global-set-key [delete] 'delete-char)
(global-set-key [kp-delete] 'delete-char)
(global-set-key "\C-h" 'backward-delete-char)
(global-set-key "\C-x\ ?" 'help)
(global-set-key "\C-c\ l" 'goto-line)
(global-set-key "\C-x\ f" 'find-file-other-window)
(global-set-key "\C-x\ \C-r" 'recentf-open-files)
(global-set-key [home] 'beginning-of-buffer)
(global-set-key [end] 'end-of-buffer)
(global-set-key "\C-z" nil)


;; go right to an empty buffer
(setq inhibit-startup-message t)

;; translates ANSI colors into text-properties, for eshell
(autoload 'ansi-color-for-comint-mode-on "ansi-color" nil t)
(add-hook 'shell-mode-hook 'ansi-color-for-comint-mode-on)

;; cvs stuff
(setq vc-default-back-end 'CVS)
(autoload 'cvs-add "cvs-add" "CVS add" t)
(autoload 'cvs-commit "cvs-commit" "CVS commit" t)
(autoload 'cvs-diff "cvs-diff" "CVS diff" t)

;; recentf stuff
(require 'recentf)
(recentf-mode 1)
(setq recentf-max-menu-items 25)

;; mode stuff
(setq auto-mode-alist (cons '("\\.php$" . php-mode) auto-mode-alist))
(autoload 'ruby-mode "ruby-mode" nil t)
(setq auto-mode-alist (cons '("\\.rb$" . ruby-mode) auto-mode-alist))

;; autorevert stuff
(autoload 'auto-revert-mode "autorevert" nil t)
(autoload 'turn-on-auto-revert-mode "autorevert" nil nil)
(autoload 'global-auto-revert-mode "autorevert" nil t)
(global-auto-revert-mode 1)

(defalias 'yes-or-no-p 'y-or-n-p)
(setq auto-save-interval 50)
(setq list-matching-lines-default-context-lines 1) ;; for M-x occur

;; counting functions
(defalias 'lc 'count-lines-page)

(defun wc ()
"Count the words in the current buffer, show the result in the minibuffer"
(interactive) ; *** This is the line that you need to add
(goto-char (point-min))
(let ((count 0))
(while (forward-word 1)
(setq count(1+ count)))
(message "There are %d words in the buffer" count)))))

;; normally disabled by default
(put 'downcase-region 'disabled nil)
(put 'upcase-region 'disabled nil)

;; Highlights the selected region
(transient-mark-mode t)