gzip
gzip is a data compression utility maintained by the GNU project that uses Lempel-Ziv (LZ77) encoding. It is commonly paired with archivers such as tar prior to compression. Therefore, it is common to see files compressed with gzip that end in .gz, .tar.gz and .tgz extensions among others.
gzip can be considered the standard and historical GNU compressor. Although still very relevant, it is less frequently used for package distribution due to lower compression ratios compared to more modern algorithms (such as the xz format provided by app-arch/xz-utils ).
Installation
USE flags
USE flags for app-arch/gzip Standard GNU compressor
pic
disable optimized assembly code that is not PIC friendly
static
!!do not set this during bootstrap!! Causes binaries to be statically linked instead of dynamically
verify-sig
Verify upstream signatures on distfiles
Emerge
root #emerge --ask app-arch/gzipUsage
There are several related utilities included in with the gzip package.
| Binary | Description |
|---|---|
| gunzip | Decompresses files compressed using the gzip compression algorithm. Restores a gzip-compressed file to its original form |
| gzexe | Compresses executable files using the gzip compression algorithm. Reduces the size of executable files, potentially saving disk space |
| gzip | A popular compression utility used to compress files using the gzip compression algorithm. Reduces the size of files, making them more efficient for storage or transmission |
| zcat | Displays the contents of a compressed file on the terminal without decompressing it. Reads the compressed file and outputs the uncompressed contents |
| zcmp | Compares two compressed files byte by byte. Checks if the compressed files are identical by decompressing them and comparing. |
| zdiff | Displays the differences between two compressed files. Decompresses the files and shows the differing lines side by side. |
| zegrep | Searches for a pattern or regular expression in compressed files. Decompresses the files and performs the search using extended regular expressions. |
| zfgrep | Searches for a fixed string pattern in compressed files. Decompresses the files and searches for the fixed string within them. |
| zforce | Forces compression or recompression of files using the gzip compression algorithm. Can update or overwrite compressed files even if the resulting file may not be smaller. |
| zgrep | Searches for a pattern or regular expression in compressed files. Decompresses the files and performs the search using basic regular expressions. |
| zless | Views the contents of compressed files one screen at a time. Decompresses the file and displays the contents in a pager-like interface. |
| zmore | Displays the contents of a compressed file page by page. Decompresses the file and shows the uncompressed contents in a controlled manner. |
| znew | Recompresses files in the ".Z" format to the ".gz" format. Converts files compressed with the older "compress" utility to the gzip compression format. |
Invocation
user $gzip --helpUsage: gzip [OPTION]... [FILE]... Compress or uncompress FILEs (by default, compress FILES in-place). Mandatory arguments to long options are mandatory for short options too. -c, --stdout write on standard output, keep original files unchanged -d, --decompress decompress -f, --force force overwrite of output file and compress links -h, --help give this help -k, --keep keep (don't delete) input files -l, --list list compressed file contents -L, --license display software license -n, --no-name do not save or restore the original name and timestamp -N, --name save or restore the original name and timestamp -q, --quiet suppress all warnings -r, --recursive operate recursively on directories --rsyncable make rsync-friendly archive -S, --suffix=SUF use suffix SUF on compressed files --synchronous synchronous output (safer if system crashes, but slower) -t, --test test compressed file integrity -v, --verbose verbose mode -V, --version display version number -1, --fast compress faster -9, --best compress better With no FILE, or when FILE is -, read standard input. Report bugs to <bug-gzip@gnu.org>.
Parallelization
gzip itself does not support parallel compression or decompression. app-arch/pigz however can be used for parallel compression by some tools, either opportunistically (e.g. Dracut), or if configured (like tar).
As a result of some tools using pigz opportunistically, simply installing pigz can be useful even without configuration. To maximize the usage of pigz, enable the pigz USE flag on app-alternatives/gzip which will create a symlink from gzip to pigz.
The gzip format does not lend itself to parallel decompression and the zlib/pigz maintainer has stated it is not possible for pigz to be extended for it [1] .
Removal
Unmerge
root #emerge --ask --depclean --verbose app-arch/gzipSee also
- Bzip2 — high-quality, patent free file compressor using the Burrows-Wheeler algorithm.
- Data compression — a list of some of the compression and file-archiver utilities available in Gentoo Linux
- 7zip — a file archiver.
- tar — an archiver tool that provides the ability to create tar archives, as well as various other kinds of manipulation.
- xz — LZMA2-based data compression utility.
- zip — provides classic ZIP compression
External references
- app-arch/pigz - a parallel implementation of gzip.
- ↑ Mark Adler. Decompressing with pigz is not parallel, pigz bug tracker, September 22nd, 2016. Retrieved on September 29th, 2022.