yuck is a command line option parser for C that works on a minimal set of dependencies - only a C compiler and the m4 macro processor are required. It supports all the standard use cases: GNU-style long options (--option), condensable short options (-xab for -x -a -b), and optional arguments to long and short options (--foo[=BAR]), multiple occurrence of options (-vvv). Most importantly, it does not depend on libc's getopt() nor getopt_long().
Gpart is a small tool which tries to guess which partitions are on a PC harddisk in case the primary partition table was damaged. It works by scanning through the device (or file) given on the commandline on a sector basis. Each guessing module is asked if it thinks a filesystem it knows about could start at a given sector. Several filesystem guessing modules are built in, and others can be added dynamically.
cqueues is a comprehensive event and networking library for Lua 5.2 and LuaJIT using modern Unix O(1) polling facilities. It includes libraries for buffered socket I/O, SSL/TLS sockets, DNS querying, signal handling, threading, file change notification, and X.509 key management. It natively supports Linux, *BSD, OS X, and Solaris systems without third-party dependencies, and is interoperable with any event loop that accepts plain descriptors, or is usable standalone.
METAXPON ("Metachron" in Greek letters) is a small and fast audio DSP library for time-scale manipulation of 16-bit integer or 32-bit floating point stereo audio data streams. It employs a rigid phase-locked vocoder with dedicated transient detection and processing, and can work in real-time or non-real-time. Four editions are included - a portable edition and three x86 editions. The portable edition can be built with any ANSI C compiler and is OS- and architecture-independent. The three x86 editions are written in assembly using the FPU, 3DNow!, and SSE instruction sets, respectively, with automatic selection between them depending on the CPU capabilities. They can be compiled with MASM, JWASM, or NASM, producing libraries of object files in 8 formats.
SYINF shows in brief a system's CPU brand and model, RAM size, disk space, operating system, regional parameters, and current date and time. It can run in interactive (menu) or batch mode. There are two versions, in the C and C++ languages. They have been tested on 20 (15) compilers, 26 (25) operating systems, and 18 architectures. (Figures in parentheses are for the C++ version.) Both versions are conveyed in source code form only, each as a single ~35 KB source text file.
tcpdump prints a description of the contents of packets on a network interface which match a given boolean expression. It can also be run with the -w flag, which causes it to save the packet data to a file for later analysis, and/or with the -r flag, which causes it to read from a saved packet file rather than to read packets from a network interface. In all cases, only packets which match the expression will be processed by tcpdump. tcpdump logs more than just TCP, IP, or ethernet packets, but has a whole suite of decoders, including ones for USB.