Emacs: Install Package with ELPA/MELPA

Starting with emacs 24 (year 2012), it comes with a package system called ELPA (Emacs Lisp Package Archive). It lets you install and manage emacs packages. [see Emacs 24.1 Features (released 2012-06)]

ELPA is a mechanism for emacs to support packages.

“ELPA” also means “GNU Emacs Lisp Package Archive”, a emacs lisp package repository containing packages sactioned by Free Software Foundation.

MELPA (Milkypostman's Emacs Lisp Package Archive) is a ELPA-compatible package repository. It contains some thousands times more packages than ELPA.

Quick Start

Add this to your emacs init:

( when (>= emacs-major-version 24) ( require 'package) ( add-to-list ' package-archives '( "melpa" . "https://melpa.org/packages/" ) t ))

restart emacs.

Emacs Alt + x list-packages

To install a package:

Alt + x list-packages . Find the package you want, move cursor to the line, press Enter . A description pane will pop up. Put cursor on the pane, press Tab to move cursor to the “Install” button then press Enter . The package is now installed. Read the package doc to see what command to start it, if necessary. (no restart is needed)

By default, packages are installed at ~/.emacs.d/elpa/

You can go to that directory, open the package you are interested, and read the file header doc.

Following are details.

Listing Available Packages

Alt + x list-packages .

Install Packages

This list is shown in package-menu-mode . In this mode, here's the most useful keys:

Enter ( package-menu-describe-package ) → Describe the package under cursor.

( ) → Describe the package under cursor. i ( package-menu-mark-install ) → mark for installation.

( ) → mark for installation. u ( package-menu-mark-unmark ) → unmark.

( ) → unmark. d ( package-menu-mark-delete ) → mark for deletion (removal of a installed package).

( ) → mark for deletion (removal of a installed package). x ( package-menu-execute ) → for “execute” (start install/uninstall of marked items).

( ) → for “execute” (start install/uninstall of marked items). r ( package-menu-refresh ) → refresh the list from server.

(For complete list of keys, Alt + x describe-mode )

For example, i want to install the clojure-mode . I type i to mark it, x to run install. Then, i got the following files in my dir, all automatically byte-compiled and loaded.

~/.emacs.d/elpa/clojure-mode-1.7.1: clojure-mode-autoloads.el clojure-mode-pkg.el clojure-mode-pkg.elc clojure-mode.el clojure-mode.elc

and now i can call clojure-mode , and it works right there! (no need to restart, but for some packages, you may need to turn it on or restart emacs.)

Upgrade Packages

To upgrade packages, just press U x .

package-menu-mark-upgrades 【 U 】 → For any package that has a new version, the installed one will be marked “D” (for delete), and new one will be marked “I” (to install).

【 】 → For any package that has a new version, the installed one will be marked “D” (for delete), and new one will be marked “I” (to install). package-menu-execute 【 x 】 → run the marked commands on packages.

WARNING: package upgrade is not reliable. It is better to upgrade one package at a time. First delete the package, then install the latest.

Package Location

New packages are installed at ~/.emacs.d/elpa/ .

If you want to remove all external packages, you can delete this entire directory and restart emacs. It is harmless to do so.

Package Repositories

The source of the packages are from package servers. There are several.

http://elpa.gnu.org/ Default. Official GNU Emacs package repository. This repository contains the minimal set, and each package is copyrighted by Free Software Foundation.

http://marmalade-repo.org/ Marmalade. More extensive number of packages.

https://melpa.org/ MELPA. As of 2017-03-25 , MELPA has most packages, and updated daily.

Note: the emacs package system, called ELPA (aka package.el), is started by Tom Tromey. Marmalade is started by Nathan Weizenbaum. MELPA is started by Donald Ephraim Curtis (aka milkypostman) http://milkbox.net/ Thank you guys.

Helpful Commands and Variables

package-enable-at-startup . By default, this is t (true).

package-load-list . This determines which packages should be loaded at start-up.

Alt + x describe-function or describe-variable for details.