Star is a very fast, POSIX-compliant tar archiver, maintained for more than 30 years. It saves many files together into a single tape or disk archive, and can restore individual files from the archive. It includes command line interfaces for the "tar", "Sun-Tar", "cpio", "pax", and "gnutar" command-line syntax. It includes a FIFO for speed, a pattern matcher, multi-volume support, the ability to archive sparse files and ACLs, the ability to archive extended file flags, automatic archive format detection, automatic byte order recognition, automatic archive compression/decompression, remote archives, and special features that allow star to be used for full and incremental backups. It includes the only known platform independent "rmt" server program.
Dar is a shell command that makes backup of a directory tree and files. Its features include splitting archives over several files, DVD, CD, ZIP, or floppies, compression, full or differential backups, strong encryption, proper saving and restoration of hard links, extended attributes, file forks, Door inodes, and sparse files, remote backup using pipes and external commands (such as ssh), and rearrangement of the "slices" of an existing archive. It can run commands between slices, before and after saving some defined files or directories (for a proper database backup, for example), and quickly retrieve individual files from differential and full backups. Several external GUIs exist as alternatives to its CLI interface, like kdar, DarGUI, SaraB, etc.
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).
PBZIP2 is a parallel implementation of the bzip2 block-sorting file compressor that uses pthreads and achieves near-linear speedup on SMP machines. The output of this version is fully compatible with bzip2 1.0.2 or newer (ie: anything compressed with PBZIP2 can be decompressed with bzip2).
Freedup finds and eliminates duplicate files by linking them, and thus reduces the amount of used disk space within one or more file systems. By default, hardlinks are used on a single device, symbolic links when the devices differ. A set of options allows you to modify the methods of file comparison, the hash functions, the linking behavior, and the reporting style. You may use batch or interactive mode. Freedup usually only considers identical files, but when comparing audio or graphics files, you may elect to ignore the tags.
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.
SCZ is a set of simple, portable, light-weight file compression and decompression utilities. Simple compress and decompress subroutines can be linked and called within applications to compress or unpack data on the fly. These functions can also be used through stand-alone utilities. The initial set of routines implements a lossless compression algorithm, so restoration and decompression are perfect.