Here are some examples of doing certain commonly desired things with Lisp expressions:
Add a directory to the variable
load-path. You can then put Lisp libraries that are not included with Emacs in this directory, and load them with
M-x load-library. See Lisp Libraries.
(add-to-list 'load-path "/path/to/lisp/libraries")
TABin C mode just insert a tab if point is in the middle of a line.
(setq c-tab-always-indent nil)
Here we have a variable whose value is normally
tfor “true" and the alternative is
Make searches case sensitive by default (in all buffers that do not override this).
(setq-default case-fold-search nil)
This sets the default value, which is effective in all buffers that do not have local values for the variable (see Locals). Setting
setqaffects only the current buffer’s local value, which is probably not what you want to do in an init file.
Specify your own email address, if Emacs can’t figure it out correctly.
(setq user-mail-address "firstname.lastname@example.org")
Various Emacs packages, such as Message mode, consult
user-mail-addresswhen they need to know your email address. See Mail Headers.
Make Text mode the default mode for new buffers.
(setq-default major-mode 'text-mode)
text-modeis used because it is the command for entering Text mode. The single-quote before it makes the symbol a constant; otherwise,
text-modewould be treated as a variable name.
Set up defaults for the Latin-1 character set, which supports most of the languages of Western Europe.
Turn off Line Number mode, a global minor mode.
Turn on Auto Fill mode automatically in Text mode and related modes (see Hooks).
(add-hook 'text-mode-hook 'auto-fill-mode)
Load the installed Lisp library named
foo(actually a file
foo.elin a standard Emacs directory).
When the argument to
loadis a relative file name, not starting with ‘
/’ or ‘
loadsearches the directories in
load-path(see Lisp Libraries).
Load the compiled Lisp file
foo.elcfrom your home directory.
Here a full file name is used, so no searching is done.
Tell Emacs to find the definition for the function
myfunctionby loading a Lisp library named
mypackage(i.e., a file
(autoload 'myfunction "mypackage" "Do what I say." t)
Here the string
"Do what I say."is the function’s documentation string. You specify it in the
autoloaddefinition so it will be available for help commands even when the package is not loaded. The last argument,
t, indicates that this function is interactive; that is, it can be invoked interactively by typing
M-x myfunction RETor by binding it to a key. If the function is not interactive, omit the
Rebind the key
C-x lto run the function
make-symbolic-link(see Init Rebinding).
(global-set-key "\C-xl" 'make-symbolic-link)
(define-key global-map "\C-xl" 'make-symbolic-link)
Note once again the single-quote used to refer to the symbol
make-symbolic-linkinstead of its value as a variable.
Do the same thing for Lisp mode only.
(define-key lisp-mode-map "\C-xl" 'make-symbolic-link)
Redefine all keys which now run
next-linein Fundamental mode so that they run
(substitute-key-definition 'next-line 'forward-line
One reason to undefine a key is so that you can make it a prefix. Simply defining
C-x C-v anythingwill make
C-x C-va prefix, but
C-x C-vmust first be freed of its usual non-prefix definition.
$’ have the syntax of punctuation in Text mode. Note the use of a character constant for ‘
(modify-syntax-entry ?\$ "." text-mode-syntax-table)
Enable the use of the command
(put 'narrow-to-region 'disabled nil)
Adjusting the configuration to various platforms and Emacs versions.
Users typically want Emacs to behave the same on all systems, so the same init file is right for all platforms. However, sometimes it happens that a function you use for customizing Emacs is not available on some platforms or in older Emacs versions. To deal with that situation, put the customization inside a conditional that tests whether the function or facility is available, like this:
(if (fboundp 'blink-cursor-mode)
(if (boundp 'coding-category-utf-8)
You can also simply disregard the errors that occur if the function is not defined.
(ignore-errors (set-face-background 'region "grey75"))
setqon a variable which does not exist is generally harmless, so those do not need a conditional.