Darcs is Distributed. Every user has access to the full command set, removing boundaries between server and client or committer and non-committers.

darcs is Interactive. It asks you questions in response to simple commands, giving you choices in your work flow. Choose to record one change in a file, while ignoring another. See each patch name while updating, even view the full "diff" for interesting patches. Compare darcs' work flow with Subversion's.

darcs is Smart. Originally developed by physicist David Roundy, darcs is based on a unique algebra of patches.

This smartness lets you respond to changing demands in ways that would otherwise not be possible.

Features :
Features

Record changes locally
In darcs, the equivalent of a cvs ``commit'' is called record, because it doesn't put the change into any remote or centralized repository. Changes are always recorded locally, meaning no net access is required in order to work on your project and record changes as you make them. Moreover, this means that there is no need for a separate ``disconnected operation'' mode.

Interactive records
You can choose to perform an interactive record, in which case darcs will prompt you for each change you have made and ask if you wish to record it. Of course, you can tell darcs to record all the changes in a given file, or to skip all the changes in a given file, or go back to a previous change, or whatever. There is also an experimental graphical interface, which allows you to view and choose changes even more easily, and in whichever order you like.

Unrecord local changes
As a corollary to the ``local'' nature of the record operation, if a change hasn't yet been published to the world--that is, if the local repository isn't accessible by others--you can safely unrecord a change (even if it wasn't the most recently recorded change) and then re-record it differently, for example if you forgot to add a file, introduced a bug or realized that what you recorded as a single change was really two separate changes.

Interactive everything else
Most darcs commands support an interactive interface. The ``revert'' command, for example, which undoes unrecorded changes has the same interface as record, so you can easily revert just a single change. Pull, push, send and apply all allow you to view and interactively select which changes you wish to pull, push, send or apply.

Test suites
Darcs has support for integrating a test suite with a repository. If you choose to use this, you can define a test command (e.g. ``make check'') and have darcs run that command on a clean copy of the project either prior to recording a change or prior to applying changes--and to reject changes that cause the test to fail.

Any old server
Darcs does not require a specialized server in order to make a repository available for read access. You can use http, ftp, or even just a plain old ssh server to access your darcs repository.

You decide write permissions
Darcs doesn't try to manage write access. That's your business. Supported push methods include direct ssh access (if you're willing to give direct ssh access away), using sudo to allow users who already have shell access to only apply changes to the repository, or verification of gpg-signed changes sent by email against a list of allowed keys. In addition, there is good support for submission of patches by email that are not automatically applied, but can easily be applied with a shell escape from a mail reader (this is how I deal with contributions to darcs).

Symmetric repositories
Every darcs repository is created equal (well, with the exception of a ``partial'' repository, which doesn't contain a full history...), and every working directory has an associated repository. As a result, there is a symmetry between ``uploading'' and ``downloading'' changes--you can use the same commands (push or pull) for either purpose.

CGI script
Darcs has a CGI script that allows browsing of the repositories.

Portable
Darcs runs on UNIX (or UNIX-like) systems (which includes Mac OS X) as well as on Microsoft Windows.

File and directory moves
Renames or moves of files and directories, of course are handled properly, so when you rename a file or move it to a different directory, its history is unbroken, and merges with repositories that don't have the file renamed will work as expected.

Token replace
You can use the ``darcs replace'' command to modify all occurrences of a particular token (defined by a configurable set of characters that are allowed in ``tokens'') in a file. This has the advantage that merges with changes that introduce new copies of the old token will have the effect of changing it to the new token--which comes in handy when changing a variable or function name that is used throughout a project.

Configurable defaults
You can easily configure the default flags passed to any command on either a per-repository or a per-user basis or a combination thereof.