Versions tested: 1.3.3
Optimal parameters: -5
Links: www.gzip.org
Authors: Jean-loup Gailly
Algorithms: LZ+HUF
Notable peformances: -

gzip

Gzip reduces the size of the named files using Lempel-Ziv coding (LZ77).

Gzip uses the Lempel-Ziv algorithm used in zip and PKZIP. The amount of compression obtained depends on the size of the input and the distribution of common substrings. Typically, text such as source code or English is reduced by 60-70%. Compression is generally much better than that achieved by LZW (as used in compress), Huffman coding (as used in pack), or adaptive Huffman coding (compact).

Compression is always performed, even if the compressed file is slightly larger than the original. The worst case expansion is a few bytes for the gzip file header, plus 5 bytes every 32K block, or an expansion ratio of 0.015% for large files. Note that the actual number of used disk blocks almost never increases. gzip preserves the mode, ownership and timestamps of files when compressing or decompressing.

the program documentation

 

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Qualified configurations
Ver Rating CPR DPR S.E. R.E. Ratio C. kB/s D. kB/s
-1
1.3.3 8 10 2 215 0 2.467 38105 88796
-3
1.3.3 11 14 3 216 0 2.556 30597 91268
-5
1.3.3 16 19 6 204 0 2.659 22808 92702
-7
1.3.3 13 13 7 145 0 2.685 14441 93715
-9
1.3.3 6 6 7 68 0 2.692 6246 94101

Version info

1.3.3, tar: yes, mode: 64-bit, crc32: 820a6cac, decoder: 36 kB, tested: 2010 Apr 16
compression: gzip.exe <args> <src>
decompression: gzip.exe -d <cfile>
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