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Diffstat (limited to 'README')
| -rw-r--r-- | README | 28 |
1 files changed, 16 insertions, 12 deletions
@@ -12,7 +12,12 @@ little memory as 50 kB, irrespective of the dictionary size used to compress the file. Of course, the smaller the output 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. +when decompressing to a regular file and is intended for systems without +enough memory (RAM + swap) to keep the whole dictionary at once. + +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 lzip file format is designed for long-term data archiving. It is clean, provides very safe 4 factor integrity checking, and is backed by @@ -23,12 +28,6 @@ bzip2, which makes it safer than decompressors returning ambiguous warning values (like gunzip) when it is used as a back end for tar or zutils. -Lunzip replaces every file given in the command line with a decompressed -version of itself. Each decompressed file has the same modification -date, permissions, and, when possible, ownership as the corresponding -compressed file. Lunzip is able to read from some types of non regular -files if the "--stdout" option is specified. - Lunzip attempts to guess the name for the decompressed file from that of the compressed file as follows: @@ -36,6 +35,15 @@ filename.lz becomes filename filename.tlz becomes filename.tar 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 +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. + 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. @@ -45,10 +53,6 @@ two or more compressed files. The result is the concatenation of the corresponding uncompressed files. Integrity testing of concatenated compressed files is also supported. -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 ideas embodied in lunzip are due to (at least) the following people: Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrey Markov (for the definition of Markov chains), G.N.N. Martin (for the definition of @@ -56,7 +60,7 @@ range encoding), Igor Pavlov (for putting all the above together in LZMA), and Julian Seward (for bzip2's CLI). -Copyright (C) 2010, 2011, 2012, 2013 Antonio Diaz Diaz. +Copyright (C) 2010, 2011, 2012, 2013, 2014 Antonio Diaz Diaz. This file is free documentation: you have unlimited permission to copy, distribute and modify it. |