============================================================================ lzop -- a real-time compressor ============================================================================ Author : Markus Franz Xaver Johannes Oberhumer http://www.infosys.tuwien.ac.at/Staff/lux/marco/lzop.html Version : 0.94 Date : 15-Oct-1997 Introduction ------------ Welcome to the fourth public release of lzop. lzop is a compressor similiar to gzip. Its main advantages over gzip are much higher compression and decompression speed. lzop was designed with the following goals in mind: 1) reliability 2) speed (both compression and decompression) 3) reasonable drop-in compatibility to gzip 4) portability Short documentation ------------------- General functionality and behaviour has been modelled very closely after gzip. Due to lack of documentation at this time you are advised to consult the gzip manual pages first. The main differences between lzop and gzip are: - Files compressed by lzop will have the suffix `.lzo' - lzop does not store or verify a checksum when compressing and decompressing a file by default. You have to use the option `-C' if you want this behaviour. - lzop does not delete the input file(s) by default. You have to use the option `-U' if you want this behaviour. Compression levels ------------------ lzop currently offers three compression levels of the LZO1X algorithm. - the default level (`-5') offers pretty fast compression - level `-1' can be even a little bit faster in some cases - but most times you won't notice the difference - level `-9' is mainly intended for generating pre-compressed data - it is somewhat slow Decompression is *very* fast for all levels. Modes of operation ------------------ lzop allows you to deal with your files in many flexible ways: - single file mode: individually (de-)compress each file - pipe mode: (de-)compress from stdin to stdout - stdout mode: (de-)compress to stdout - archive mode: compress/extract multiple files into a single archive file Here are some usage examples for each of the modes: * single file mode (like gzip) create lzop a.c -> create a.c.lzo lzop a.c b.c -> create a.c.lzo & b.c.lzo lzop -U a.c b.c -> create a.c.lzo & b.c.lzo and delete a.c & b.c lzop *.c extract lzop -d a.c.lzo -> restore a.c lzop -df a.c.lzo -> restore a.c, overwrite if already exists lzop -d *.lzo list lzop -l a.c.lzo lzop -l *.lzo lzop -lv *.lzo -> be verbose test lzop -t a.c.lzo lzop -tq *.lzo -> be quiet * pipe mode (like gzip) create lzop < a.c > y.lzo cat a.c | lzop > y.lzo tar -cf - *.c | lzop > y.tar.lzo -> create a compressed tar file extract lzop -d < y.lzo > a.c lzop -d < y.tar.lzo | tar -xvf - -> extract a tar file lzop -d < y.tar.lzo | tar -tvf - -> list a tar file list lzop -l < y.lzo cat y.lzo | lzop -l test lzop -t < y.lzo cat y.lzo | lzop -t * stdout mode (like gzip) create lzop -c a.c > y.lzo extract lzop -dc y.lzo > a.c lzop -dc y.tar.lzo | tar -tvf - -> list a tar file * archive mode (similiar to zip/zoo/lha/rar) create lzop a.c b.c -o sources.lzo -> create an archive lzop -c *.c > sources.lzo -> another way to create an archive lzop -c *.h >> sources.lzo -> add files to archive extract lzop -dN sources.lzo lzop -x ../src/sources.lzo -> extract to current directory lzop -x -p/tmp < ../src/sources.lzo -> extract to /tmp directory list lzop -lNv sources.lzo test lzop -t sources.lzo Related links ------------- Precompiled binaries for some platforms will be available from the lzop home page soon. see http://www.infosys.tuwien.ac.at/Staff/lux/marco/lzop.html lzop uses the LZO data compression library for compression services. see http://www.infosys.tuwien.ac.at/Staff/lux/marco/lzo.html The gzip home page can be found at http://www.gzip.org The future ---------- - write some real documentation - anything you find useful... Copyright --------- lzop is Copyright (C) 1996, 1997 Markus Franz Xaver Johannes Oberhumer lzop is distributed under the terms of the GNU General Public License (GPL). See the file COPYING.