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- This is the file README for the gzip distribution, version 0.6.
-
- gzip (GNU zip) is a compression utility designed to be a replacement
- for 'compress'. Its main advantages over compress are much better
- compression and freedom from patented algorithms. The GNU Project
- intends to make this the standard compression program for its system.
-
- gzip currently uses by default the LZ77 algorithm used in zip 1.9 (the
- portable pkzip compatible archiver). The gzip format was however
- designed to accomodate several compression algorithms. Future
- versions of gzip may optionally support compression with the LZW
- algorithm to produce files compatible with compress 3.0 to 4.2.
-
- gunzip can currently decompress files in gzip deflate format, zip
- format or 'compress' format. The detection of the input format is
- automatic. When using the first two formats, gunzip checks a 32 bit
- CRC. (The 'compress' format does not allow this.)
-
- gzip produces files with a .z extension. This was chosen to mimic the
- 'compress' .Z extension. Using exactly the same extension would have
- caused too much confusion. Using a completely different extension
- would have forced changes in other programs such as GNU tar (which has
- a -z option). The .z extension is already used by the 'pack'
- Huffman encoder, but this program is rarely used because it does not
- compress well.
-
- This version 0.6 is a beta release. Several planned features are not
- yet supported (see the file TODO). The lzw compression code is not
- provided in this version to avoid the IBM patent 4,814,746 and the
- Unisys patent 4,558,302. The encryption code is not provided because
- of the US export rules.
-
- See the file INSTALL for installation instructions. See the file NEWS
- for a summary of changes since 0.5.
-
- WARNING: at least on the NeXT, "gcc -finline-functions" is broken.
- gzip produces valid .z files but they are much too large because
- the string matching code misses most matches. Use "gcc -O" instead.
- Use "make test" to check that gzip was compiled correctly.
-
- Please send all comments and bug reports by electronic mail to:
- Jean-loup Gailly <jloup@chorus.fr>
-
- or, if this fails, to bug-gnu-utils@prep.ai.mit.edu.
- Bug reports should ideally include:
-
- * The complete output of "gzip -V" (or the contents of revision.h
- if you can't get gzip to compile)
- * The hardware and operating system
- * The compiler used to compile
- * A description of the bug behaviour
- * The input to gzip, that triggered the bug
-
- This program is free software, you can redistribute it and/or modify
- it under the terms of the GNU General Public License, a copy of which
- is provided under the name COPYING.
-
- Many thanks to those who provided me with bug reports and feedback.
- See the files THANKS and ChangeLog for more details.
-