path: root/doc/lzop.man

LZOP(1)                                                                LZOP(1)



NAME
       lzop - compress or expand files

ABSTRACT
       lzop is a file compressor very similar to gzip.  lzop favors speed over
       compression ratio.

SYNOPSIS
       lzop [ command ] [ options ] [ filename ...  ]

       lzop [-dxlthIVL19] [-qvcfFnNPkU] [-o file] [-p[path]] [-S suffix]
       [filename ...]

DESCRIPTION
       lzop reduces the size of the named files. Whenever possible, each file
       is compressed into one with the extension .lzo, while keeping the same
       ownership modes, access and modification times. If no files are
       specified, or if a file name is "-", lzop tries to compress the
       standard input to the standard output. lzop will only attempt to
       compress regular files or symbolic links to regular files.  In
       particular, it will ignore directories.

       If the compressed file name is too long for its file system, lzop
       truncates it.

       Compressed files can be restored to their original form using lzop -d.
       lzop -d takes a list of files on its command line and decompresses each
       file whose name ends with .lzo and which begins with the correct magic
       number to an uncompressed file without the original extension. lzop -d
       also recognizes the special extension .tzo as shorthand for .tar.lzo.
       When compressing, lzop uses the .tzo extension if necessary instead of
       truncating a file with a .tar extension.

       lzop stores the original file name, mode and time stamp in the
       compressed file. These can be used when decompressing the file with the
       -d option. This is useful when the compressed file name was truncated
       or when the time stamp was not preserved after a file transfer.

       lzop preserves the ownership, mode and time stamp of files when
       compressing. When decompressing lzop restores the mode and time stamp
       if present in the compressed files.  See the options -n, -N, --no-mode
       and --no-time for more information.

       lzop always keeps original files unchanged unless you use the option
       -U.

       lzop uses the LZO data compression library for compression services.
       The amount of compression obtained depends on the size of the input and
       the distribution of common substrings.  Typically, text such as source
       code or English is compressed into 40-50% of the original size, and
       large files usually compress much better than small ones. Compression
       and decompression speed is generally much faster than that achieved by
       gzip, but compression ratio is worse.

   COMPRESSION LEVELS
       lzop offers the following compression levels of the LZO1X algorithm:

       -3  the default level offers pretty fast compression.  -2, -3, -4, -5
           and -6 are currently all equivalent - this may change in a future
           release.

       -1, --fast
           can be even a little bit faster in some cases - but most times you
           won't notice the difference

       -7, -8, -9, --best
           these compression levels are mainly intended for generating pre-
           compressed data - especially -9 can be somewhat slow

       Decompression is very fast for all compression levels, and
       decompression speed is not affected by the compression level.

MAIN COMMAND
       If no other command is given then lzop defaults to compression (using
       compression level -3).

       -#, --fast, --best
           Regulate the speed of compression using the specified digit #,
           where -1 or --fast indicates the fastest compression method (less
           compression) and -9 or --best indicates the slowest compression
           method (best compression). The default compression level is -3.

       -d, --decompress, --uncompress
           Decompress. Each file will be placed into same the directory as the
           compressed file.

       -x, --extract
           Extract compressed files to the current working directory. This is
           the same as '-dPp'.

       -t, --test
           Test. Check the compressed file integrity.

       -l, --list
           For each compressed file, list the following fields:

             method: compression method
             compressed: size of the compressed file
             uncompr.: size of the uncompressed file
             ratio: compression ratio
             uncompressed_name: name of the uncompressed file

           In combination with the --verbose option, the following fields are
           also displayed:

             date & time: time stamp for the uncompressed file

           With --name, the uncompressed name, date and time are those stored
           within the compress file if present.

           With --verbose, the size totals and compression ratio for all files
           is also displayed. With --quiet, the title and totals lines are not
           displayed.

           Note that lzop defines compression ratio as compressed_size /
           uncompressed_size.

       --ls, --ls=FLAGS
           List each compressed file in a format similar to ls -ln.

           The following flags are currently honoured:
             F  Append a '*' for executable files.
             G  Inhibit display of group information.
             Q  Enclose file names in double quotes.

       --info
           For each compressed file, list the internal header fields.

       -I, --sysinfo
           Display information about the system and quit.

       -L, --license
           Display the lzop license and quit.

       -h, -H, --help
           Display a help screen and quit.

       -V  Version. Display the version number and compilation options and
           quit.

       --version
           Version. Display the version number and quit.

OPTIONS
       -c, --stdout, --to-stdout
           Write output on standard output. If there are several input files,
           the output consists of a sequence of independently (de)compressed
           members. To obtain better compression, concatenate all input files
           before compressing them.

       -o FILE, --output=FILE
           Write output to the file FILE. If there are several input files,
           the output consists of a sequence of independently (de)compressed
           members.

       -p, -pDIR, --path=DIR
           Write output files into the directory DIR instead of the directory
           determined by the input file. If DIR is omitted, then write to the
           current working directory.

       -f, --force
           Force lzop to

            - overwrite existing files
            - (de-)compress from stdin even if it seems a terminal
            - (de-)compress to stdout even if it seems a terminal
            - allow option -c in combination with -U

           Using -f two or more times forces things like

            - compress files that already have a .lzo suffix
            - try to decompress files that do not have a valid suffix
            - try to handle compressed files with unknown header flags

           Use with care.

       -F, --no-checksum
           Do not store or verify a checksum of the uncompressed file when
           compressing or decompressing.  This speeds up the operation of lzop
           a little bit (especially when decompressing), but as unnoticed data
           corruption can happen in case of damaged compressed files the usage
           of this option is not generally recommended.  Also, a checksum is
           always stored when compressing with one of the slow compression
           levels (-7, -8 or -9), regardless of this option.

       -n, --no-name
           When decompressing, do not restore the original file name if
           present (remove only the lzop suffix from the compressed file
           name). This option is the default under UNIX.

       -N, --name
           When decompressing, restore the original file name if present. This
           option is useful on systems which have a limit on file name length.
           If the original name saved in the compressed file is not suitable
           for its file system, a new name is constructed from the original
           one to make it legal.  This option is the default under DOS,
           Windows and OS/2.

       -P  When decompressing, restore the original path and file name if
           present.  When compressing, store the relative (and cleaned) path
           name.  This option is mainly useful when using archive mode - see
           usage examples below.

       --no-mode
           When decompressing, do not restore the original mode (permissions)
           saved in the compressed file.

       --no-time
           When decompressing, do not restore the original time stamp saved in
           the compressed file.

       -S .suf, --suffix=.suf
           Use suffix .suf instead of .lzo. The suffix must not contain
           multiple dots and special characters like '+' or '*', and suffixes
           other than .lzo should be avoided to avoid confusion when files are
           transferred to other systems.

       -k, --keep
           Do not delete input files. This is the default.

       -U, --unlink, --delete
           Delete input files after successful compression or decompression.
           Use this option to make lzop behave like gzip and bzip2.  Note that
           explicitly giving -k overrides -U.

       --crc32
           Use a crc32 checksum instead of an adler32 checksum.

       --no-warn
           Suppress all warnings.

       --ignore-warn
           Suppress all warnings, and never exit with exit status 2.

       -q, --quiet, --silent
           Suppress all warnings and decrease the verbosity of some commands
           like --list or --test.

       -v, --verbose
           Verbose. Display the name for each file compressed or decompressed.
           Multiple -v can be used to increase the verbosity of some commands
           like --list or --test.

       --  Specifies that this is the end of the options. Any file name after
           -- will not be interpreted as an option even if it starts with a
           hyphen.

OTHER OPTIONS
       --no-stdin
           Do not try to read standard input (but a file name "-" will still
           override this option).  In old versions of lzop, this option was
           necessary when used in cron jobs (which do not have a controlling
           terminal).

       --filter=NUMBER
           Rarely useful.  Preprocess data with a special "multimedia" filter
           before compressing in order to improve compression ratio.  NUMBER
           must be a decimal number from 1 to 16, inclusive.  Using a filter
           slows down both compression and decompression quite a bit, and the
           compression ratio usually doesn't improve much either...  More
           effective filters may be added in the future, though.

           You can try --filter=1 with data like 8-bit sound samples,
           --filter=2 with 16-bit samples or depth-16 images, etc.

           Un-filtering during decompression is handled automatically.

       -C, --checksum
           Deprecated. Only for compatibility with very old versions as lzop
           now uses a checksum by default. This option will get removed in a
           future release.

       --no-color
           Do not use any color escape sequences.

       --mono
           Assume a mono ANSI terminal. This is the default under UNIX (if
           console support is compiled in).

       --color
           Assume a color ANSI terminal or try full-screen access. This is the
           default under DOS and in a Linux virtual console (if console
           support is compiled in).

ADVANCED USAGE
       lzop allows you to deal with your files in many flexible ways. Here are
       some usage examples:

       backup mode
          tar --use-compress-program=lzop -cf archive.tar.lzo files..

          This is the recommended mode for creating backups.
          Requires GNU tar or a compatible version which accepts the
          '--use-compress-program=XXX' option.

       single file mode: individually (de)compress each file
         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: (de)compress from stdin to stdout
         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

         list
           lzop -l < y.lzo
           cat y.lzo | lzop -l
           lzop -d < y.tar.lzo | tar -tvf -     -> list a tar file

         test
           lzop -t < y.lzo
           cat y.lzo | lzop -t

       stdout mode: (de)compress to stdout
         create
           lzop -c a.c > y.lzo

         extract
           lzop -dc y.lzo > a.c
           lzop -dc y.tar.lzo | tar -xvf -      -> extract a tar file

         list
           lzop -dc y.tar.lzo | tar -tvf -      -> list a tar file

       archive mode: compress/extract multiple files into a single archive
       file
         create
           lzop a.c b.c -o sources.lzo          -> create an archive
           lzop -P src/*.c -o sources.lzo       -> create an archive, store path name
           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
           lzop -tvv sources.lzo                -> be very verbose

       If you wish to create a single archive file with multiple members so
       that members can later be extracted independently, you should prefer a
       full-featured archiver such as tar. The latest version of GNU tar
       supports the --use-compress-program=lzop option to invoke lzop
       transparently.  lzop is designed as a complement to tar, not as a
       replacement.

ENVIRONMENT
       The environment variable LZOP can hold a set of default options for
       lzop. These options are interpreted first and can be overwritten by
       explicit command line parameters.  For example:

           for sh/ksh/zsh:    LZOP="-1v --name"; export LZOP
           for csh/tcsh:      setenv LZOP "-1v --name"
           for DOS/Windows:   set LZOP=-1v --name

       On Vax/VMS, the name of the environment variable is LZOP_OPT, to avoid
       a conflict with the symbol set for invocation of the program.

       Not all of the options are valid in the environment variable - lzop
       will tell you.

SEE ALSO
       bzip2(1), gzip(1), tar(1), xz(1)

       Precompiled binaries for some platforms are available from the lzop
       home page.

           see http://www.oberhumer.com/opensource/lzop/

       lzop uses the LZO data compression library for compression services.

           see http://www.oberhumer.com/opensource/lzo/

DIAGNOSTICS
       Exit status is normally 0; if an error occurs, exit status is 1. If a
       warning occurs, exit status is 2 (unless option --ignore-warn is in
       effect).

       lzop's diagnostics are intended to be self-explanatory.

BUGS
       No bugs are known. Please report all problems immediately to the
       author.

AUTHOR
       Markus Franz Xaver Johannes Oberhumer <markus@oberhumer.com>
       http://www.oberhumer.com/opensource/lzop/

COPYRIGHT
       lzop and the LZO library are Copyright (C) 1996-2017 Markus Franz Xaver
       Oberhumer <markus@oberhumer.com>.  All Rights Reserved.

       lzop and the LZO library are distributed under the terms of the GNU
       General Public License (GPL).

       Legal info: If want to integrate lzop into your commercial
       (backup-)system please carefully read the GNU GPL FAQ at
       http://www.gnu.org/licenses/gpl-faq.html about possible implications.



lzop 1.04                         2017-08-10                           LZOP(1)