Ziproxy is a high-performance forwarding (non-caching) HTTP proxy that gzips text and HTML files, and reduces the size of images by converting them to lower quality JPEGs or JPEG 2000. It is intended to increase the speed for low-speed Internet connections (mobile, dial-up, other). It's suitable for both home and professional usage. Ziproxy is fully configurable and also features transparent proxy mode, HTML/JS/CSS optimization, operation in daemon mode, a detailed access log with compression statistics, basic authentication, and more.
makeself is a small shell script that generates a self-extractable compressed TAR archive from a directory. The resulting file appears as a shell script, and can be launched as is. The archive will then uncompress itself to a temporary directory and an arbitrary command will be executed (for example, an installation script). This is pretty similar to archives generated with WinZip Self-Extractor in the Windows world.
RabbIt is a mutating, caching Web proxy used to speed up surfing over slow links like modems. It does this by removing advertising and background images and scaling down images to low quality JPEGs. RabbIT is written in Java and should be able to run on any platform. It does depend upon an image converter if image scaling is on. The recommended image converter is "convert" from the ImageMagick package.
Various archive formats can be created, extracted, tested, listed, searched, compared, and repacked by patool. The advantage of patool is its simplicity in handling archive files without having to remember myriad programs and options. The archive format is determined by the file(1) program and as a fallback by the archive file extension. patool supports 7z (.7z), ACE (.ace), ADF (.adf), ALZIP (.alz), APE (.ape), AR (.a), ARC (.arc), ARJ (.arj), bzip2 (.bz2), CAB (.cab), COMPRESS (.Z), CPIO (.cpio), deb (.deb), DMS (.dms), FLAC (.flac), gzip (.gz), ISO (.iso), LRZIP (.lrz), LZH (.lha, .lzh), LZIP (.lz), LZMA (.lzma), LZOP (.lzo), RPM (.rpm), RAR (.rar), RZIP (.rz), SHN (.shn), tar (.tar), XZ (.xz), zip (.zip, .jar), and ZOO (.zoo) formats. It relies on helper applications to handle those archive formats (for example bzip2 for BZIP2 archives). The archive formats tar, zip, bzip2, and gzip are supported natively and do not require helper applications to be installed.
LZO is a portable lossless data compression library written in ANSI C. It offers pretty fast compression and very fast decompression. Decompression requires no memory. In addition there are slower compression levels achieving a quite competitive compression ratio while still decompressing at this very high speed.
Pysync has both a demonstration implementation of the rsync and related algorithms in pure Python, and a high speed librsync Python extension. The pure Python is not fast and is not optimized, however it does work and provides a simple implementation of the algorithm for reference and experimentation. It includes a combination of ideas taken from librsync, xdelta, and rsync. The librsync Python extension is less flexible and harder to understand, but is very fast.
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.
Lessfs is a high performance inline data deduplicating file system for Linux. Lessfs complies to the POSIX standard and is very useful for backup purposes as well as providing storage for virtual machine images. Although lessfs is a file system that is implemented in user space with FUSE, it offers decent performance. Lessfs is capable of handling data rates up to 350MB/sec. It supports filesystem encryption.