What is Emacs ?

Emacs is the extensible, customizable, self-documenting real-time display editor. This Editor is used to do a lot of things, from IRC to reading mails and news, along with "basic" editing, advanced macro, remote control, multimedia player, and so on..

This webpage is about EMMS, an Emacs "package" that you use to extend Emacs features to multimedia.

The cute EMMS logo

Developing EMMS

The definitive version of this page is available as an EmacsWiki page. This is just a static copy to be used in case the wiki page is vandalized.


  1. Prerequisites
  2. Shared project repo
    1. Picking a branch
  3. Using the archive
    1. Keeping up-to-date
    2. Telling git your name
    3. Committing changes
    4. Giving changes back
  4. Becoming an EMMS Developer
  5. Emacs modes, Tutorials, and Documentation


You will need to install git.

There is a Debian package called git-core that you can install if you use Debian or Ubuntu. If you are using Windows, then visit http://code.google.com/p/msysgit/. Mac OS X users may visit http://code.google.com/p/git-osx-installer/. Otherwise, visit http://git.or.cz and download the latest source.

Shared project repo

If you are a developer that is registered with the EMMS project on Savannah, you will want to do the following, replacing loginname with your Savannah login name.

        $ git clone ssh://loginname@git.sv.gnu.org/srv/git/emms.git

Note that this will not work until you have added your SSH key to Savannah.

If you do not have developer access but wish to track the latest development changes, do one of the following instead. If you are behind a restrictive firewall, use the second method; otherwise, use the first method.


        $ git clone git://git.sv.gnu.org/emms.git


        $ git clone http://git.sv.gnu.org/r/emms.git

Picking a branch

To see a list of the available branches, run the following command in the checked out copy of EMMS.

        $ git branch -r

Here is a description of the available branches.

HEAD The branch you are currently on
master Main development branch

If you want to browse the available branches via the web, visit http://git.sv.gnu.org/gitweb/?p=emms.git;a=summary.

The default branch that you get when cloning the EMMS project is master.

To see which branch you are currently on, do:

        $ git branch

To check out a branch, do the following. This changes the contents of the current directory to match that branch, rather than creating a new directory.

        $ git checkout [branch name]

For the shared branch, this would be the following.

        $ git checkout master

Using the archive

Keeping up-to-date

To keep up-to-date on the latest EMMS happenings, run git’s pull command from the directory that contains your copy of EMMS.

        $ git pull origin

This will update EMMS, taking care to preserve any changes that you have checked in to your local copy.

Telling git your name

If you have made some changes that you would like to commit to the EMMS project, first you will need to provide a name and email address. This information is used in the change log for each change you commit. To do this, edit the .gitconfig file in your home directory to include the following contents.

        name = Your Name Goes Here
        email = you@yourdomain.example.com


Now you are ready to make the change log, and then commit. Read on for the change log instructions before doing the commit.

Committing changes

If you wish to commit just a few files that you have changed, instead of all the files that you have changed, then do the following.

        $ git add changed-file-1
        $ git add changed-file-2
        $ git commit

If you instead wish to commit all changes in one go, then do:

        $ git commit -a

In both cases, git will open an editor that you can use to make a log message. Add a brief one-line description of your changes at the top of the file.

The rest of the file (keeping a blank line after the very first line) is for describing your changes in detail. If you want, you can either leave this blank or just copy the relevant part of your ChangeLog entry here. The information you use here will appear in the emms-patches mailing list when you are done, once you have either pushed your changes or a developer has committed a patch that you have sent.

Make sure that you have described your changes in the ChangeLog file before committing, or at minimum, use ChangeLog-style syntax in your log entries (or something similar to it).

Here is one example of an acceptable commit log.

emms-player-mpd: Integrate with emms-lastfm to show track.

* emms-lastfm.el (emms-lastfm-np): Expand to take optional callback
  argument.  Rename `arg' to `insertp' for clarity.

* emms-player-mpd.el (emms-player-mpd-show-1): Detect if
  emms-lastfm is activated, and if the current track is a LastFM
  URL.  If so, call emms-lastfm-np rather than continuing on.
  (emms-player-mpd-show): Docfix.

Giving changes back

If you have changes that you have committed to EMMS, they are only local to your copy of EMMS so far. If you want to share them, you must either push them back to the shared repo, or email them to the emms-patches AT gnu.org mailing list.

If you have developer access to the shared archive, you can push changes back by doing:

        $ git push origin

If you do not yet have developer access, read on.

You may send your changes via email by doing:

        $ git format-patch -M origin

and then sending the generated patch files to the emms-patches mailing list. Be sure to describe your changes and include a sample ChangeLog entry for them. Be sure that the patch is the body of the message, and not an attachment. Any comments that you wish to make, but don’t want to appear in the commit log, should be placed between the “---” and the diffstat.

If you want to send the resulting patches from the commandline, rather than opening up an email client, you can do the following, where PATCH-FILE is the file that git format-patch made:

        $ git send-email --to emms-patches@gnu.org PATCH-FILE

Becoming an EMMS Developer

If you want commit access to the shared EMMS repository on Savannah, then register an account at http://sv.gnu.org/ (be sure to add an SSH key), browse to the EMMS project at http://sv.gnu.org/p/emms, and request to be added to the group. It would be best to send some patches to the emms-patches AT gnu.org mailing list first, so that we know that you know what you are doing.

Alternatively, you can submit patches from your own repo, if you don’t mind waiting on someone to apply them to the shared repo.

You must also be willing to sign a copyright assignment for your changes to EMMS, since EMMS is a GNU project. The current maintainer (mwolson AT gnu.org) will assist you in this process if you contact him.

Emacs modes, Tutorials, and Documentation

DVC is a highly-recommended Emacs add-on that allows you to see changes that you have made, log messages, and (eventually) merging changes easily between branches.

Alternatively, the development version of Emacs should include some regular VC bindings for git, so that you can use the same key-bindings that you would use for CVS.

git’s documentation may be browsed at the git website. There has been a significant effort since March 2007 to make the documentation more thorough and easy to read. Several tutorials are there, as well as a User’s Manual.