![]() ^ "Can gzip compress several files into a single archive?"."GZIP file format specification version 4.3". ^ The 'application/zlib' and 'application/gzip' Media Types.ĪdvanceCOMP and 7-Zip can produce gzip-compatible files, using an internal DEFLATE implementation with better compression ratios than gzip itself-at the cost of more processor time compared to the reference implementation. It produces considerably smaller files (especially for source code and other structured text), but at the cost of memory and processing time (up to a factor of 4). Since the late 1990s, bzip2, a file compression utility based on a block-sorting algorithm, has gained some popularity as a gzip replacement. Zlib DEFLATE is used internally by the Portable Network Graphics (PNG) format. Still, the gzip format is sometimes recommended over zlib because Internet Explorer does not implement the standard correctly and cannot handle the zlib format as specified in RFC 1950. This RFC also specifies a zlib format (called "DEFLATE"), which is equal to the gzip format except that gzip adds eleven bytes of overhead in the form of headers and trailers. It is one of the three standard formats for HTTP compression as specified in RFC 2616. ![]() The gzip format is used in HTTP compression, a technique used to speed up the sending of HTML and other content on the World Wide Web. The zlib stream format, DEFLATE, and the gzip file format were standardized respectively as RFC 1950, RFC 1951, and RFC 1952. Zlib is an abstraction of the DEFLATE algorithm in library form which includes support both for the gzip file format and a lightweight data stream format in its API. Optionally, -v ( verbose) lists files as they are being extracted. tar.gz files by passing the z option, e.g., tar -zxf, where -z instructs decompression, -x means extraction, and -f specifies the name of the compressed archive file to extract from. The tar utility included in most Linux distributions can extract. Data from blocks not demolished by damage that are located afterward may be recoverable through difficult workarounds. Damage recovery ĭata in blocks prior to the first damaged part of the archive is usually fully readable. Pigz, written by Mark Adler, is compatible with gzip and speeds up compression by using all available CPU cores and threads. It achieves gzip-compatible compression using more exhaustive algorithms, at the expense of compression time required. These implementations originally come from NetBSD, and support decompression of bzip2 and the Unix pack format.Īn alternative compression program achieving 3-8% better compression is Zopfli. FreeBSD, DragonFly BSD and NetBSD use a BSD-licensed implementation instead of the GNU version it is actually a command-line interface for zlib intended to be compatible with the GNU implementation's options. The 'g' in this specific version stands for gratis. OpenBSD's version of gzip is actually the compress program, to which support for the gzip format was added in OpenBSD 3.4. The most commonly known is the GNU Project's implementation using Lempel-Ziv coding (LZ77). Various implementations of the program have been written. Implementations NetBSD Gzip / FreeBSD Gzip Developer(s)Ĭvsweb. The ZIP format can hold collections of files without an external archiver, but is less compact than compressed tarballs holding the same data, because it compresses files individually and cannot take advantage of redundancy between files ( solid compression). Gzip is not to be confused with the ZIP archive format, which also uses DEFLATE. ![]() The final compressed file usually has the extension. ![]() Compressed archives are typically created by assembling collections of files into a single tar archive (also called tarball), and then compressing that archive with gzip. Īlthough its file format also allows for multiple such streams to be concatenated (gzipped files are simply decompressed concatenated as if they were originally one file), gzip is normally used to compress just single files.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |