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Diffstat (limited to 'README')
| -rw-r--r-- | README | 46 |
1 files changed, 22 insertions, 24 deletions
@@ -5,22 +5,21 @@ small size makes it well suited for embedded devices or software installers that need to decompress files but don't need compression capabilities. Lunzip is fully compatible with lzip-1.4 or newer. -The lzip file format is designed for data sharing and long-term -archiving, taking into account both data integrity and decoder -availability: +The lzip file format is designed for data sharing and long-term archiving, +taking into account both data integrity and decoder availability: * The lzip format provides very safe integrity checking and some data - recovery means. The lziprecover program can repair bit-flip errors + recovery means. The lziprecover program can repair bit flip errors (one of the most common forms of data corruption) in lzip files, and provides data recovery capabilities, including error-checked merging of damaged copies of a file. * The lzip format is as simple as possible (but not simpler). The - lzip manual provides the source code of a simple decompressor along - with a detailed explanation of how it works, so that with the only - help of the lzip manual it would be possible for a digital - archaeologist to extract the data from a lzip file long after - quantum computers eventually render LZMA obsolete. + lzip manual provides the source code of a simple decompressor + along with a detailed explanation of how it works, so that with + the only help of the lzip manual it would be possible for a + digital archaeologist to extract the data from a lzip file long + after quantum computers eventually render LZMA obsolete. * Additionally the lzip reference implementation is copylefted, which guarantees that it will remain free forever. @@ -30,26 +29,25 @@ repair the nearer it is from the beginning of the file. Therefore, with the help of lziprecover, losing an entire archive just because of a corrupt byte near the beginning is a thing of the past. -Lunzip uses the same well-defined exit status values used by lzip and -bzip2, which makes it safer than decompressors returning ambiguous -warning values (like gunzip) when it is used as a back end for other -programs like tar or zutils. +Lunzip uses the same well-defined exit status values used by lzip, which +makes it safer than decompressors returning ambiguous warning values (like +gunzip) when it is used as a back end for other programs like tar or zutils. -Lunzip provides a "low memory" mode able to decompress any file using as +Lunzip provides a 'low memory' mode able to decompress any file using as little memory as 50 kB, irrespective of the dictionary size used to compress the file. To activate it, specify the size of the output buffer -with the "--buffer-size" option and lunzip will use the decompressed +with the '--buffer-size' option and lunzip will use the decompressed file as dictionary for distances beyond the buffer size. Of course, the smaller the buffer size used in relation to the dictionary size, the more accesses to disk are needed and the slower the decompression is. -This "low memory" mode only works when decompressing to a regular file +This 'low memory' mode only works when decompressing to a regular file and is intended for systems without enough memory (RAM + swap) to keep the whole dictionary at once. It has been tested on a laptop with a 486 processor and 4 MiB of RAM. The amount of memory required by lunzip to decompress a file is about 46 kB larger than the dictionary size used to compress that file, unless -the "--buffer-size" option is specified. +the '--buffer-size' option is specified. Lunzip attempts to guess the name for the decompressed file from that of the compressed file as follows: @@ -60,21 +58,21 @@ anyothername becomes anyothername.out Decompressing a file is much like copying or moving it; therefore lunzip preserves the access and modification dates, permissions, and, when -possible, ownership of the file just as "cp -p" does. (If the user ID or +possible, ownership of the file just as 'cp -p' does. (If the user ID or the group ID can't be duplicated, the file permission bits S_ISUID and S_ISGID are cleared). Lunzip is able to read from some types of non regular files if the -"--stdout" option is specified. +'--stdout' option is specified. If no file names are specified, lunzip decompresses from standard input to standard output. In this case, lunzip will decline to read compressed input from a terminal. -Lunzip will correctly decompress a file which is the concatenation of -two or more compressed files. The result is the concatenation of the -corresponding decompressed files. Integrity testing of concatenated -compressed files is also supported. +Lunzip will correctly decompress a file which is the concatenation of two or +more compressed files. The result is the concatenation of the corresponding +decompressed files. Integrity testing of concatenated compressed files is +also supported. The ideas embodied in lunzip are due to (at least) the following people: Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrey Markov (for @@ -83,7 +81,7 @@ range encoding), Igor Pavlov (for putting all the above together in LZMA), and Julian Seward (for bzip2's CLI). -Copyright (C) 2010-2018 Antonio Diaz Diaz. +Copyright (C) 2010-2019 Antonio Diaz Diaz. This file is free documentation: you have unlimited permission to copy, distribute and modify it. |