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Diffstat (limited to 'doc/lzip.texinfo')
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1 files changed, 39 insertions, 35 deletions
diff --git a/doc/lzip.texinfo b/doc/lzip.texinfo index 484b5ac..1c04f2c 100644 --- a/doc/lzip.texinfo +++ b/doc/lzip.texinfo @@ -6,19 +6,19 @@ @finalout @c %**end of header -@set UPDATED 11 May 2013 -@set VERSION 1.15-pre2 +@set UPDATED 15 July 2013 +@set VERSION 1.15-pre3 @dircategory Data Compression @direntry -* Lzip: (lzip). Data compressor based on the LZMA algorithm +* Lzip: (lzip). LZMA lossless data compressor @end direntry @ifnothtml @titlepage @title Lzip -@subtitle Data compressor based on the LZMA algorithm +@subtitle LZMA lossless data compressor @subtitle for Lzip version @value{VERSION}, @value{UPDATED} @author by Antonio Diaz Diaz @@ -37,13 +37,13 @@ This manual is for Lzip (version @value{VERSION}, @value{UPDATED}). @menu * Introduction:: Purpose and features of lzip * Algorithm:: How lzip compresses the data -* Invoking Lzip:: Command line interface -* File Format:: Detailed format of the compressed file -* Stream Format:: Format of the LZMA stream in lzip files +* Invoking lzip:: Command line interface +* File format:: Detailed format of the compressed file +* Stream format:: Format of the LZMA stream in lzip files * Examples:: A small tutorial with examples * Problems:: Reporting bugs * Reference source code:: Source code illustrating stream format -* Concept Index:: Index of concepts +* Concept index:: Index of concepts @end menu @sp 1 @@ -58,18 +58,33 @@ to copy, distribute and modify it. @chapter Introduction @cindex introduction -Lzip is a lossless data compressor based on the LZMA algorithm, with -very safe integrity checking and a user interface similar to the one of -gzip or bzip2. Lzip decompresses almost as fast as gzip and compresses -better than bzip2, which makes it well suited for software distribution -and data archiving. +Lzip is a lossless data compressor with a user interface similar to the +one of gzip or bzip2. Lzip decompresses almost as fast as gzip and +compresses more than bzip2, which makes it well suited for software +distribution and data archiving. Lzip is a clean implementation of the +LZMA algorithm. Lzip uses the same well-defined exit status values used by bzip2, which makes it safer when used in pipes or scripts than compressors returning ambiguous warning values, like gzip. +The lzip file format is designed for long-term data archiving and +provides very safe integrity checking. The member trailer stores the +32-bit CRC of the original data, the size of the original data and the +size of the member. These values, together with the value remaining in +the range decoder and the end-of-stream marker, provide a 4 factor +integrity checking which guarantees that the decompressed version of the +data is identical to the original. This guards against corruption of the +compressed data, and against undetected bugs in lzip (hopefully very +unlikely). The chances of data corruption going undetected are +microscopic. Be aware, though, that the check occurs upon decompression, +so it can only tell you that something is wrong. It can't help you +recover the original uncompressed data. + If you ever need to recover data from a damaged lzip file, try the -lziprecover program. +lziprecover program. Lziprecover makes lzip files resistant to bit-flip +(one of the most common forms of data corruption), and provides data +recovery capabilities, including error-checked merging of damaged files. Lzip replaces every file given in the command line with a compressed version of itself, with the name "original_name.lz". Each compressed @@ -119,18 +134,6 @@ file from that of the compressed file as follows: @item anyothername @tab becomes @tab anyothername.out @end multitable -As a self-check for your protection, lzip stores in the member trailer -the 32-bit CRC of the original data, the size of the original data and -the size of the member. These values, together with the value remaining -in the range decoder and the end-of-stream marker, provide a very safe 4 -factor integrity checking which guarantees that the decompressed version -of the data is identical to the original. This guards against corruption -of the compressed data, and against undetected bugs in lzip (hopefully -very unlikely). The chances of data corruption going undetected are -microscopic. Be aware, though, that the check occurs upon decompression, -so it can only tell you that something is wrong. It can't help you -recover the original uncompressed data. - @node Algorithm @chapter Algorithm @@ -193,8 +196,8 @@ range encoding), Igor Pavlov (for putting all the above together in LZMA), and Julian Seward (for bzip2's CLI and the idea of unzcrash). -@node Invoking Lzip -@chapter Invoking Lzip +@node Invoking lzip +@chapter Invoking lzip @cindex invoking @cindex options @cindex usage @@ -295,9 +298,10 @@ Use it together with @samp{-v} to see information about the file. @item -v @itemx --verbose Verbose mode.@* -When compressing, show the compression ratio for each file processed.@* +When compressing, show the compression ratio for each file processed. A +second -v shows the progress of compression.@* When decompressing or testing, further -v's (up to 4) increase the -verbosity level, showing status, dictionary size, compression ratio, +verbosity level, showing status, compression ratio, dictionary size, trailer contents (CRC, data size, member size), and up to 6 bytes of trailing garbage (if any). @@ -357,8 +361,8 @@ invalid input file, 3 for an internal consistency error (eg, bug) which caused lzip to panic. -@node File Format -@chapter File Format +@node File format +@chapter File format @cindex file format Perfection is reached, not when there is no longer anything to add, but @@ -432,7 +436,7 @@ facilitates safe recovery of undamaged members from multi-member files. @end table -@node Stream Format +@node Stream format @chapter Format of the LZMA stream in lzip files @cindex format of the LZMA stream @@ -1204,8 +1208,8 @@ int main( const int argc, const char * const argv[] ) @end verbatim -@node Concept Index -@unnumbered Concept Index +@node Concept index +@unnumbered Concept index @printindex cp |