plextor-tool allows owners of Plextor CD-ROM or generally MMC-compatible CD-R(W) drives (including that of Plextor) to change various properties. These include the reading speed (to "silence" the drive), the time until the drive spins down, the volume of the internal audio out, and some special settings for Plextor CD-ROM devices.
PLOTICUS is a command line utility for creating bar, line, pie, boxplot, scatterplot, sweep, heatmap, vector, timeline, Venn diagrams, and other types of charts and plots. ploticus is good for automated or just-in-time graph generation. It handles date, time, and categorical data nicely, and has some basic statistical capabilities. It can output to GIF, PNG, SVG, SWF, JPEG, PostScript, EPS, and X11. You can use convenient preset options or create complex scripts with rich and detailed color and style operations.
plumb is a shell with focus on pipes: instead of pipelines, it can build large graphs of processes (nodes) and pipes (edges). Pipes are simple unidirectional streams without side effects. Traffic can be controlled by virtual processes (which are nodes just like real processes, but are implemented in plumb for minimal overhead). Virtual processes can split, merge, regex filter/alter, and shape the streams. Timers and starting/stopping processes or even rewiring the script on the fly are also supported. It is portable (using libporty) and behaves exactly the same way on Linux, Windows, Mac OS X, many BSD variants, and older UNIX systems.
plus4emu is a portable emulator of the Commodore Plus/4 computer. It supports Windows and POSIX platforms (32 bit Windows, 32 and 64 bit Linux, and Mac OS X have been tested). It implements accurate, high quality hardware emulation, but the system requirements are higher than that of most other emulators.
pngcheck is the official PNG tester and debugger. Originally designed simply to test the CRCs within a PNG image file (e.g., to check for ASCII rather than binary transfer), it has since been extended to check and optionally print almost all the information about a PNG image and to verify that it conforms to the PNG specification. It also includes partial support for MNG animations.
pngquant is a batch conversion utility to quantize and dither truecolor PNG images, especially those with a full alpha channel, down to "RGBA-palette" PNGs (i.e., PLTE + tRNS in PNG parlance). Such images are usually two to four times smaller than the full 32-bit versions, and partial transparency is preserved quite nicely. This makes pngquant especially useful both for Web sites and for PlayStation 2 development, where one of the texture formats is RGBA-palette-based (though not PNG-compressed).