zlib is designed to be a free, general-purpose, legally unencumbered, lossless data-compression library for use on virtually any computer hardware and operating system. The zlib data format is itself portable across platforms. Unlike the LZW compression method used in Unix compress(1), the compression method currently used in zlib essentially never expands the data. (LZW can double or triple the file size in extreme cases.) zlib's memory footprint is also independent of the input data and can be reduced, if necessary, at some cost in compression.
di is a disk information utility that displays everything that df does and more. It features the ability to display your disk usage in whatever format you prefer. It also checks the user and group quotas, so that the user sees the space available for their use, not the system wide disk space. It is designed to be highly portable across many platforms and is great for heterogenous networks.
pngcrush is an excellent batch-mode compression utility for PNG images. Depending on the application that created the original PNGs, it can improve the file size anywhere from a few percent to 40% or more (completely losslessly). The utility also allows specified PNG chunks (e.g. text comments) to be inserted or deleted, and it can fix incorrect gamma info written by Photoshop 5.0 as well as the erroneous iCCP chunk written by Photoshop 5.5.
U++ is a C++ cross-platform rapid application development suite focused on programmers' productivity without sacrificing runtime performance. Based on strictly deterministic design, it provides a viable alternative to garbage-collected platforms, even for business logic oriented problems.
IP Tables State implements the "state top" feature from IP Filter for IP Tables. "State top" displays the states held by your stateful firewall in a "top"-like manner. Since IP Tables doesn't have a built-in way to easily display this information once, an option was added to iptstate to do this.
The C++ Portable Types Library (PTypes) is a simple alternative to the STL that includes multithreading and networking. It defines dynamic strings, character sets, variants, lists and other basic data types along with threads, synchronization primitives and IP sockets. It is portable across modern Unix and Windows systems and includes a sample HTTP daemon showing the full power of the library.
Nullsoft Scriptable Install System is a tool for creating quick and user-friendly installers for Microsoft Windows operating systems. It is a script-based system that adds a very small overhead, only 34 KB. It features LZMA compression, support for multiple languages, and an easy-to-use plugins system
mkconfig is a build configuration utility. It creates an output file intended to be included as a header file, run as a shell script, used as a configuration file, or any other use. mkconfig is written in portable shell script and designed to be extensible for any configuration use.