GNU Mach is the microkernel upon which a GNU Hurd system is based. It provides an Inter Process Communication (IPC) mechanism which the Hurd uses to define interfaces for implementing in a distributed multi-server fashion the services a traditional operating system kernel provides. Mach is particularly well-suited for SMP and network cluster techniques. Thread support is provided at the kernel level, and the kernel itself takes advantage of that. Network transparency at the IPC level makes resources of the system available across machine boundaries.
se is a screen-oriented version of the classic UNIX text editor ed. The editor implements many of the commands of ed, but instead of being line-oriented, se is screen-oriented. The command syntax is very familiar to users who already know ed. If you get stuck, there is a built-in help system that describes many of the available commands. Many configurable options can be loaded from a .serc file. se can be run interactively or in a script via the included scriptse utility. The editor is portable across many platforms, supporting major Linux and BSD distributions as well as other systems like GNU, Minix, Haiku, OpenSolaris, and Cygwin.
Libchop is a set of utilities and library for data backup and distributed storage. Its main application is chop-backup, an encrypted backup program that supports data integrity checks, versioning at little cost, distribution among several sites, selective sharing of stored data, adaptive compression, and more. The library itself, which chop-backup builds upon, implements storage techniques such as content-based addressing, content hash keys, Merkle trees, similarity detection, and lossless compression. It makes it easy to combine them in different ways. The ‘chop-archiver’ and ‘chop-block-server’ tools, illustrated in the manual, provide direct access to these facilities from the command line. It is written in C and has Guile (Scheme) bindings.
Artha is a handy thesaurus based on WordNet with distinct features like global hot key look up, passive desktop notification, regular expression based search, etc. Artha may be used as a free open-source replacement/clone to the proprietary WordWeb Pro thesaurus (which is also based on WordNet) on Unix-like and Windows operating systems.
Logger is a log queueing and optimization utility. It can completely replace sys/klogd, handle logs larger than 2GB, perform automatic nightly log rotation without affecting services, and transfer logs between machines via TCP connections. Any application that writes a text log can be maintained by Logger. It is light, small, and fast, emphasizes security, and reduces drive usage through memory queueing.
The MirBSD Korn Shell (mksh) is an actively developed successor of pdksh (the Public Domain Korn Shell), aimed at producing a shell good for interactive use, but with the primary focus on scripting. It is intended to be portable to most *nix-like operating systems as long as they're not too obscure. mksh incorporates improvements from OpenBSD and Debian, as well as bugfixes and enhancements developed for the MirOS, FreeWRT, and MidnightBSD projects and Android. The emacs command line editing mode is UTF-8 capable, and Byte Order Marks are ignored in scripts. The shell supports large files, as well as all pdksh and some csh, AT&T ksh, zsh, and GNU bash features, is compatible with the Bourne shell and POSIX (within limits), has no limit on array sizes, and incorporates some other useful builtins and features. While being already fast and small (without losing functionality), flags to make it even smaller can be given at compile time. An interactive shell reads "~/.mkshrc" on startup.
Wocvim is a WoC client for Vim. WoC is a protocol which enables the use of hyperlinks in plain ASCII texts. The links can point to local or remote locations. The protocol is specifically designed to support source code, but it can be used in any text. For source code, it's also possible to use ad-hoc tag generators like cscope and ctags.