Libxml2 is the XML C library developed for the Gnome project. The library code is portable (to Linux, Unix, Windows, embedded systems, etc.) and modular; most of the extensions can be compiled out. Libxml2 implements a number of existing standards related to markup languages, including the XML standard, Namespaces in XML, XML Base, Relax NG, RFC 2396, XPath, XPointer, HTML4, XInclude, SGML Catalogs, and XML Catalogs. In most cases, libxml tries to implement the specifications in a relatively strict way. To some extent, it provides support for the following specifications, but doesn't claim to implement them: DOM, FTP client, HTTP client, and SAX2. Support for W3C XML Schemas is in progress. It includes xmllint, a command line XML validator.
GraphicsMagick is a robust collection of tools and libraries which support reading, writing, and manipulating an image in over 90 major formats including popular formats like DPX, DICOM, BMP, GIF, JPEG, JPEG-2000, PDF, PNG, PNM, SVG, and TIFF. A high-quality 2D renderer is included, which provides a subset of SVG capabilities. C, C++, Perl, Tcl, and Ruby are supported. Originally based on ImageMagick, GraphicsMagick focuses on performance, minimizing bugs, and providing stable APIs and ABIs. It runs on all modern variants of Unix, Windows, and Mac OS X.
Dosage is designed to keep a local copy of specific Web comics and other picture-based content such as Picture of the Day sites. With the dosage command line, script you can get the latest strip of a Web comic, catch up to the last strip downloaded, or download a strip for a particular date/index (if the comic's site layout makes this possible).
BitTorrent is a tool for copying files from one machine to another. FTP punishes sites for being popular. Since all uploading is done from one place, a popular site needs big iron and big bandwidth. With BitTorrent, clients automatically mirror files they download, making the publisher's burden almost nothing.
Barcode Writer in Pure Postscript implements the printing of many barcode formats entirely within PostScript, so that the process of converting the input string into the printed output is performed by the printer or print system. The project supports all major barcode formats including: EAN-13 (JAN-13), EAN-8 (JAN-8), UPC-A, UPC-E, EAN-5 & EAN-2 (EAN/UPC add-ons), ISBN (including legacy ISBN), ISMN (including legacy ISMN), ISSN, Code 128 (A, B & C), GS1-128, SSCC-18 (EAN-18, NVE), EAN-14, Code 39, Code 39 Extended, Code 93, Code 93 Extended, Code 32 (Italian Pharmacode), Pharmazentralnummer (PZN), Interleaved 2 of 5, ITF-14 (UPC SCS), GS1 DataBar (Omnidirectional, Stacked, Stacked Omnidirectional, Limited, Expanded, Expanded Stacked), Code 2 of 5 (Industrial, IATA, Matrix, Datalogic & COOP), Code 11 (USD-8), BC412, Codabar (NW-7), Pharmacode (including two-track), MSI, Plessey, Telepen, Channel Code, PosiCode, PDF417, Data Matrix (ECC200), QR Code (including Micro QR Code), and more.
Libxslt is a C library for GNOME which allows developers to work with XSLT. It is based on libxml for XML parsing, tree manipulation, and XPath support. Also included is 'xsltproc', a command line XSLT processor. The library is written in plain C, making as few assumptions as possible, and sticking closely to ANSI C/POSIX for easy embedding. It should work on Linux, Unix, and Windows. Though not designed primarily with performances in mind, libxslt seems to be a relatively fast processor. It also include full support for the EXSLT set of extension functions as well as some common extensions present in other XSLT engines.
Lua is a programming language originally designed for extending applications, but also frequently used as a general-purpose, stand-alone language. It combines simple procedural syntax (similar to Pascal) with powerful data description constructs based on associative arrays and extensible semantics. It is dynamically typed, interpreted from bytecodes, and has automatic memory management, making it ideal for configuration, scripting, and rapid prototyping. It is implemented as a small library of C functions, written in ANSI C, and compiles unmodified in all known platforms. The implementation goals are simplicity, efficiency, portability, and low embedding cost. It has been used on games such as World of Warcraft, FarCry and Angry Birds, among others.
Beets is a media library management system designed for obsessive-compulsive music geeks. It catalogs your collection, automatically improving its metadata as it goes using the MusicBrainz database. It also downloads cover art for albums it imports. Then it provides a bouquet of tools for manipulating and accessing your music. Beets also includes a music player that speaks the MPD protocol, so you can play music in your beets library using any MPD client.
SCons is a software construction tool (build tool substitute for Make) implemented in Python. It features a modular build engine that can be embedded in other software. SCons configuration files are Python scripts that call the build engine API. It can scan files to detect dependencies automatically and maintain a global view of all dependencies in a build tree, and uses MD5 signatures to detect changed file contents reliably. Timestamps can be used if you prefer. SCons also supports parallel builds and is easily extensible through user-defined builder and scanner objects.