Junkie is a real-time packet sniffer and analyzer. It is modular enough to accomplish many different tasks. It can be a helpful companion to the modern network administrator and analyst. Compared to previously available tools, junkie lies in between tcpdump and wireshark. Unlike tcpdump, its purpose is to parse protocols of any depth; unlike wireshark, though, it is designed to analyze traffic in real-time and so cannot parse traffic as exhaustively as wireshark does. In addition, its design encompasses extendability and speed. It has a plug-in system and high-level extension language that eases the development and combination of new functionalities; threaded packet capture and analysis for handling of high bandwidth networks; and a modular architecture to ease the addition of any protocol layer. It is based on libpcap for portability, and well-tested on professional settings.
mu is a collection of utilities for maildirs, in particular for indexing and searching them. mu fills a database with information about your emails, which can then be queried using an easy query language. It can work stand-alone or be integrated with a mail client. It also provides an emacs-based email client ("mu4e") and bindings for Guile/Scheme.
Beast is a powerful music composition and modular synthesis application. It offers multiple input methods like multitrack, piano roll, and pattern editing and supports skins. On the technical side, it has a wide range of abilities like sequencing, unlimited undo/redo history, real-time synthesis with multiprocessor support, full duplex 32-bit audio rendering, precise timing down to sample granularity, on demand loading of partial wave files, on the fly decoding of various sample formats, aliasing free oscillators, and full Scheme scripting support.
Upmf is a source-based package manager written almost completely in Scheme. The user is able to search, build, and remove packages. Since Scheme through GUILE is very extensible, the user can customize the procedures, or even exchange them with his own, if wanted. Packages are stored in their own self-contained directories and are incorporated into the filesystem with help of GNU Stow.
Chicken is a Scheme compiler that translates most of R5RS Scheme into relatively portable C. It supports fully general tail-call recursion, first-class continuations, and has a very flexible and efficient interface to C and C++. Chicken implements several extensions to the Scheme language: lightweight threads, pattern matching macros, dynamic loading of compiled code, and various object-oriented paradigms, such as TinyCLOS, and others. The library system includes hundreds of convenient modules for practical use.
dfsch is Scheme-like LISP dialect. It draws inspiration from R5RS, but also contains concepts inspired by other languages, mainly Common Lisp, most notable of which is inclusion of a CLOS-style object system with multiple dispatch and condition systems. The implementation is written in plain C with a Boehm-Demers-Weiser conservative garbage collector using some object-oriented concepts on top of plain C.