UnZip will list, test, or extract files from a ZIP archive, commonly found on DOS and Windows systems. A companion program, Zip, creates ZIP archives; both are part of the Info-ZIP project. Both programs are compatible with archives created by PKWARE's PKZIP or Nico Mak's WinZip, but in many cases the program options or default behaviors differ.
Zip is a compression and file packaging utility for Unix, VMS, DOS, OS/2, Windows 9x/NT, Amiga, Atari, Macintosh, BeOS, SMS/QDOS, MVS, VM/CMS, and others. It is analogous to a combination of the Unix commands tar(1) and compress(1) and is compatible with PKWARE's PKZIP and Nico Mak's WinZip. It's part of the Info-ZIP project.
PACT is a self-contained set of tools which support developing and using portable programs, particularly scientific and engineering applications. By defining a single, higher level, standard programming interface, it shields application developers from the plethora of different hardware architectures and operating systems and their non-standard features.
The pnmtopng package contains the official pnmtopng and pngtopnm utilities for use with the rest of the PBMplus/NetPBM suite. They are among the best PNG-supporting applications available, with automatic detection of grayscale or palette images and excellent heuristics for creating the smallest possible PNG images.