Clzip is a lossless data compressor with a user interface similar to the one of gzip or bzip2. Clzip decompresses almost as fast as gzip and compresses more than bzip2, which makes it well suited for software distribution and data archiving. Clzip uses the lzip file format; the files produced by clzip are fully compatible with lzip-1.4 or newer, and can be rescued with lziprecover. Clzip is, in fact, a C language implementation of lzip, intended for embedded devices or systems lacking a C++ compiler. The lzip file format is designed for long-term data archiving and provides very safe integrity checking.
GCC-MELT is a high-level domain specific language that eases the development of plugin-like extensions for GCC, the Gnu Compiler Collection. These extensions can analyze or modify GCC internal representations, and can be used for static source code analysis, refactoring, specific warnings, optimizations, etc. The MELT language provides high-level features. Notably, MELT code is translated to C or C++, and can even contain C or C++ code. It includes powerful pattern matching facilities and can manipulate dynamically typed values and raw GCC structures. It enables functional/applicative, object-oriented, reflective programming styles and has a familiar Lisp-like syntax.
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.
Plzip is a massively parallel (multi-threaded), lossless data compressor based on the lzlib compression library, with a user interface similar to the one of lzip, bzip2, or gzip. It can compress/decompress large files on multiprocessor machines much faster than lzip, at the cost of a slightly-reduced compression ratio. On files large enough (several GB), plzip can use hundreds of processors. On files of only a few MB, it is better to use lzip. Plzip uses the lzip file format, and the files produced by plzip are fully compatible with lzip-1.4 or newer, and can be rescued with lziprecover.
GNU Recutils is a set of tools and libraries to access human-editable text-based databases called recfiles. A recfile contains data structured as a sequence of records. The rec format supports data integrity with the usage of record descriptors (keys, mandatory fields, field types, etc.) as well as the ability of record fields to refer to other records. Despite its simplicity, recfiles can be used to store medium-sized databases. The GNU recutils suite comprises a texinfo manual describing the Rec format, a C library (librec) providing a rich set of functions to access rec files, a set of C utilities that can be used in shell scripts and in the command line to operate on rec files, and an Emacs mode (rec-mode).