rarch (Removable Archive) is a program that keeps a database of archives on removable media (i.e., CDs). It can be used to keep an archive of backup CDs, etc. It comes with a search function, easy archive creation functionality, and other archive management functions. It does not create and manage the archives themselves; it only keeps a database of what files are on what archives, so that they can be searched.
ratproxy is a semi-automated, largely passive Web application security audit tool optimized for accurate and sensitive detection, and automatic annotation, of potential problems and security-relevant design patterns based on the observation of existing, user-initiated traffic in complex Web 2.0 environments.
Ruby appscript (rb-appscript) is a high-level, user-friendly Apple event bridge that allows you to control scriptable MacOS X applications using ordinary Ruby scripts. It is a port of the powerful, mature Python appscript package, making Ruby a serious alternative to Apple's own AppleScript language for automating your Mac.
rdiff-backup backs up one directory to another. The target directory ends up a copy of the source directory, but extra reverse diffs are stored in a special directory so you can still recover files lost some time ago. The idea is to combine the best features of a mirror and an incremental backup. rdiff-backup can also operate in a bandwidth- efficient manner over a pipe, like rsync. Thus you can use rdiff-backup and ssh to securely back up to a remote location, and only the differences will be transmitted. It can also handle symlinks, device files, permissions, ownership, etc., so it can be used on the entire file system.
reSIProcate is a high performance, object-oriented, C++ sip stack that is compliant with RFC 3261. It includes support for a wide variety of operating systems, including Windows and Linux. It has full support for UDP, TCP, and TLS transports on both IPv4 and IPv6. It also implements the full set of specifications for DNS usage in SIP, including NAPTR and SRV lookups (RFCs: 3263, 2915, 2782) using an asynchronous DNS library (ares).
reacTIVision is a computer vision framework for the fast and robust tracking of fiducial markers attached to physical objects, as well as for multi-touch finger tracking. It was mainly designed as a toolkit for the rapid development of table-based tangible user interfaces and interactive multi-touch surfaces such as the reacTable. Client application examples are available for various programming environments such as C++, Java, C#, Processing, PureData, Max/MSP, and Quartz Composer.