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.
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.
The CFD General Notation System (CGNS) provides a general, portable, and extensible standard for the storage and retrieval of computational fluid dynamics (CFD) analysis data. CGNS is designed to facilitate the exchange of data between sites and applications, and to help stabilize the archiving of aerodynamic data.
clapf is a high performance email content filter application. It includes a statistical (inverse chi-square) antispam module, an interface to several anti-virus products, and a Web UI (including a spam quarantine) written in PHP. It supports virtual users, URL- and IP-address blacklists, whitelists, LDAP directories, policy groups, minefield, and many more features. clapf can be used as an after queue content filter with Postfix (including as an appliance) and Exim or via the maildrop local delivery agent (LDA). It's also ideal to act as a spamfilter appliance in front of an Exchange server.
gif2png is a simple command-line utility to convert images from GIF to PNG format. It automatically preserves transparency, interlacing and text comments, and it can do multiple images in one command (e.g., gif2png *.gif). The distribution also includes a web2png script that can be used to convert an entire web tree; it calls gif2png to do image conversions, then patches IMG SRC tags correctly in referring pages.