LilyPond Contributor's Guide: 1.2 Overview of work flow

## 1.2 Overview of work flow

Ultra-short summary for Unix developers: source code is at `git://git.sv.gnu.org/lilypond.git`. Documentation is built with Texinfo, after pre-processing with `lilypond-book`. Send well-formed patches to lilypond-devel@gnu.org.

Git is a version control system that tracks the history of a program’s source code. The LilyPond source code is maintained as a Git repository, which contains:

- all of the source files needed to build LilyPond, and
- a record of the entire history of every change made to every file since the program was born.

The ‘official’ LilyPond Git repository is hosted by the GNU Savannah software forge at http://git.sv.gnu.org. Although, since Git uses a distributed model, technically there is no central repository. Instead, each contributor keeps a complete copy of the entire repository (about 116M).

Changes made within one contributor’s copy of the repository can be shared with other contributors using patches. A patch is a simple text file generated by the `git` program that indicates what changes have been made (using a special format). If a contributor’s patch is approved for inclusion (usually through the mailing list), someone on the current development team will push the patch to the official repository.

The Savannah software forge provides two separate interfaces for viewing the LilyPond Git repository online: cgit and gitweb. The cgit interface should work faster than gitweb in most situations, but only gitweb allows you to search through the source code using `grep`, which you may find useful. The cgit interface is at http://git.sv.gnu.org/cgit/lilypond.git/ and the gitweb interface is at http://git.sv.gnu.org/gitweb/?p=lilypond.git.

Git is a complex and powerful tool, but tends to be confusing at first, particularly for users not familiar with the command line and/or version control systems. We have created the `lily-git` graphical user interface to ease this difficulty.

Compiling (‘building’) LilyPond allows developers to see how changes to the source code affect the program itself. Compiling is also needed to package the program for specific operating systems or distributions. LilyPond can be compiled from a local Git repository (for developers), or from a downloaded tarball (for packagers). Compiling LilyPond is a rather involved process, and most contributor tasks do not require it.

Contributors can contact the developers through the ‘lilypond-devel’ mailing list. The mailing list archive is located at http://lists.gnu.org/archive/html/lilypond-devel/. If you have a question for the developers, search the archives first to see if the issue has already been discussed. Otherwise, send an email to lilypond-devel@gnu.org. You can subscribe to the developers’ mailing list here: http://lists.gnu.org/mailman/listinfo/lilypond-devel.

Note: Contributors on Windows or MacOS X wishing to compile code or documentation are strongly advised to use our Ubuntu LilyPond Developer Remix, as discussed in Quick start.

#### LilyPond — Contributor’s Guide