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authorDaniel Baumann <mail@daniel-baumann.ch>2015-11-07 15:36:59 +0000
committerDaniel Baumann <mail@daniel-baumann.ch>2015-11-07 15:36:59 +0000
commit3d3968e451576fa317143140cb93242dba81f418 (patch)
treeedb3c6b69183c590ba38029242bd01614e426818 /doc/plzip.info
parentAdding debian version 1.1-1. (diff)
downloadplzip-3d3968e451576fa317143140cb93242dba81f418.tar.xz
plzip-3d3968e451576fa317143140cb93242dba81f418.zip
Merging upstream version 1.2~pre1.
Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>
Diffstat (limited to 'doc/plzip.info')
-rw-r--r--doc/plzip.info188
1 files changed, 99 insertions, 89 deletions
diff --git a/doc/plzip.info b/doc/plzip.info
index 7461e06..717471c 100644
--- a/doc/plzip.info
+++ b/doc/plzip.info
@@ -1,5 +1,4 @@
-This is plzip.info, produced by makeinfo version 4.13 from
-plzip.texinfo.
+This is plzip.info, produced by makeinfo version 4.13+ from plzip.texi.
INFO-DIR-SECTION Data Compression
START-INFO-DIR-ENTRY
@@ -12,7 +11,7 @@ File: plzip.info, Node: Top, Next: Introduction, Up: (dir)
Plzip Manual
************
-This manual is for Plzip (version 1.1, 17 September 2013).
+This manual is for Plzip (version 1.2-pre1, 20 January 2014).
* Menu:
@@ -24,7 +23,7 @@ This manual is for Plzip (version 1.1, 17 September 2013).
* Concept index:: Index of concepts
- Copyright (C) 2009, 2010, 2011, 2012, 2013 Antonio Diaz Diaz.
+ Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014 Antonio Diaz Diaz.
This manual is free documentation: you have unlimited permission to
copy, distribute and modify it.
@@ -41,12 +40,9 @@ the one of lzip, bzip2 or gzip.
Plzip can compress/decompress large files on multiprocessor machines
much faster than lzip, at the cost of a slightly reduced compression
-ratio. On files large enough (several GB), plzip can use hundreds of
-processors. On files of only a few MB it is better to use lzip.
-
- Plzip uses the same well-defined exit status values used by lzip and
-bzip2, which makes it safer when used in pipes or scripts than
-compressors returning ambiguous warning values, like gzip.
+ratio. Note that the number of usable threads is limited by file size,
+so on files larger than a few GB plzip can use hundreds of processors,
+but on files of only a few MB plzip is no faster than lzip.
Plzip uses the lzip file format; the files produced by plzip are
fully compatible with lzip-1.4 or newer, and can be rescued with
@@ -71,12 +67,27 @@ lziprecover program. Lziprecover makes lzip files resistant to bit-flip
recovery capabilities, including error-checked merging of damaged copies
of a file.
- Plzip replaces every file given in the command line with a compressed
-version of itself, with the name "original_name.lz". Each compressed
-file has the same modification date, permissions, and, when possible,
-ownership as the corresponding original, so that these properties can be
-correctly restored at decompression time. Plzip is able to read from
-some types of non regular files if the `--stdout' option is specified.
+ Plzip uses the same well-defined exit status values used by lzip and
+bzip2, which makes it safer than compressors returning ambiguous warning
+values (like gzip) when it is used as a back end for tar or zutils.
+
+ When compressing, plzip replaces every file given in the command line
+with a compressed version of itself, with the name "original_name.lz".
+When decompressing, plzip attempts to guess the name for the
+decompressed file from that of the compressed file as follows:
+
+filename.lz becomes filename
+filename.tlz becomes filename.tar
+anyothername becomes anyothername.out
+
+ (De)compressing a file is much like copying or moving it; therefore
+plzip 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).
+
+ Plzip is able to read from some types of non regular files if the
+'--stdout' option is specified.
If no file names are specified, plzip compresses (or decompresses)
from standard input to standard output. In this case, plzip will
@@ -88,19 +99,12 @@ two or more compressed files. The result is the concatenation of the
corresponding uncompressed files. Integrity testing of concatenated
compressed files is also supported.
- When decompressing, plzip attempts to guess the name for the
-decompressed file from that of the compressed file as follows:
-
-filename.lz becomes filename
-filename.tlz becomes filename.tar
-anyothername becomes anyothername.out
-
WARNING! Even if plzip is bug-free, other causes may result in a
corrupt compressed file (bugs in the system libraries, memory errors,
etc). Therefore, if the data you are going to compress is important,
-give the `--keep' option to plzip and do not remove the original file
+give the '--keep' option to plzip and do not remove the original file
until you verify the compressed file with a command like
-`plzip -cd file.lz | cmp file -'.
+'plzip -cd file.lz | cmp file -'.

File: plzip.info, Node: Program design, Next: Invoking plzip, Prev: Introduction, Up: Top
@@ -137,73 +141,78 @@ The format for running plzip is:
Plzip supports the following options:
-`-h'
-`--help'
+'-h'
+'--help'
Print an informative help message describing the options and exit.
-`-V'
-`--version'
+'-V'
+'--version'
Print the version number of plzip on the standard output and exit.
-`-B BYTES'
-`--data-size=BYTES'
+'-B BYTES'
+'--data-size=BYTES'
Set the input data block size in bytes. The input file will be
divided in chunks of this size before compression is performed.
Valid values range from 8 KiB to 1 GiB. Default value is two times
the dictionary size. Plzip will reduce the dictionary size if it
is larger than the chosen data size.
-`-c'
-`--stdout'
+'-c'
+'--stdout'
Compress or decompress to standard output. Needed when reading
from a named pipe (fifo) or from a device.
-`-d'
-`--decompress'
+'-d'
+'--decompress'
Decompress.
-`-f'
-`--force'
+'-f'
+'--force'
Force overwrite of output files.
-`-F'
-`--recompress'
- Force recompression of files whose name already has the `.lz' or
- `.tlz' suffix.
+'-F'
+'--recompress'
+ Force recompression of files whose name already has the '.lz' or
+ '.tlz' suffix.
-`-k'
-`--keep'
+'-k'
+'--keep'
Keep (don't delete) input files during compression or
decompression.
-`-m BYTES'
-`--match-length=BYTES'
+'-m BYTES'
+'--match-length=BYTES'
Set the match length limit in bytes. After a match this long is
found, the search is finished. Valid values range from 5 to 273.
Larger values usually give better compression ratios but longer
compression times.
-`-n N'
-`--threads=N'
+'-n N'
+'--threads=N'
Set the number of worker threads. Valid values range from 1 to "as
many as your system can support". If this option is not used,
plzip tries to detect the number of processors in the system and
- use it as default value. `plzip --help' shows the system's default
+ use it as default value. 'plzip --help' shows the system's default
value.
-`-o FILE'
-`--output=FILE'
- When reading from standard input and `--stdout' has not been
- specified, use `FILE' as the virtual name of the uncompressed
- file. This produces a file named `FILE' when decompressing, and a
- file named `FILE.lz' when compressing.
+ Note that the number of usable threads is limited to
+ ceil( file_size / data_size ) during compression (*note
+ --data-size::), and to the number of members in the input during
+ decompression.
+
+'-o FILE'
+'--output=FILE'
+ When reading from standard input and '--stdout' has not been
+ specified, use 'FILE' as the virtual name of the uncompressed
+ file. This produces a file named 'FILE' when decompressing, and a
+ file named 'FILE.lz' when compressing.
-`-q'
-`--quiet'
+'-q'
+'--quiet'
Quiet operation. Suppress all messages.
-`-s BYTES'
-`--dictionary-size=BYTES'
+'-s BYTES'
+'--dictionary-size=BYTES'
Set the dictionary size limit in bytes. Valid values range from 4
KiB to 512 MiB. Plzip will use the smallest possible dictionary
size for each member without exceeding this limit. Note that
@@ -216,33 +225,33 @@ The format for running plzip is:
requirement is affected at compression time by the choice of
dictionary size limit.
-`-t'
-`--test'
+'-t'
+'--test'
Check integrity of the specified file(s), but don't decompress
them. This really performs a trial decompression and throws away
- the result. Use it together with `-v' to see information about
+ the result. Use it together with '-v' to see information about
the file.
-`-v'
-`--verbose'
+'-v'
+'--verbose'
Verbose mode.
When compressing, show the compression ratio for each file
- processed. A second -v shows the progress of compression.
+ 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, compression ratio, decompressed
size, and compressed size.
-`-1 .. -9'
+'-1 .. -9'
Set the compression parameters (dictionary size and match length
- limit) as shown in the table below. Note that `-9' can be much
- slower than `-1'. These options have no effect when decompressing.
+ limit) as shown in the table below. Note that '-9' can be much
+ slower than '-1'. These options have no effect when decompressing.
The bidimensional parameter space of LZMA can't be mapped to a
linear scale optimal for all files. If your files are large, very
- repetitive, etc, you may need to use the `--match-length' and
- `--dictionary-size' options directly to achieve optimal
- performance. For example, `-9m64' usually compresses executables
- more (and faster) than `-9'.
+ repetitive, etc, you may need to use the '--match-length' and
+ '--dictionary-size' options directly to achieve optimal
+ performance. For example, '-9m64' usually compresses executables
+ more (and faster) than '-9'.
Level Dictionary size Match length limit
-1 1 MiB 5 bytes
@@ -255,13 +264,13 @@ The format for running plzip is:
-8 24 MiB 132 bytes
-9 32 MiB 273 bytes
-`--fast'
-`--best'
+'--fast'
+'--best'
Aliases for GNU gzip compatibility.
Numbers given as arguments to options may be followed by a multiplier
-and an optional `B' for "byte".
+and an optional 'B' for "byte".
Table of SI and binary prefixes (unit multipliers):
@@ -316,15 +325,15 @@ additional information before, between, or after them.
All multibyte values are stored in little endian order.
-`ID string'
+'ID string'
A four byte string, identifying the lzip format, with the value
"LZIP" (0x4C, 0x5A, 0x49, 0x50).
-`VN (version number, 1 byte)'
+'VN (version number, 1 byte)'
Just in case something needs to be modified in the future. 1 for
now.
-`DS (coded dictionary size, 1 byte)'
+'DS (coded dictionary size, 1 byte)'
Lzip divides the distance between any two powers of 2 into 8
equally spaced intervals, named "wedges". The dictionary size is
calculated by taking a power of 2 (the base size) and substracting
@@ -336,18 +345,18 @@ additional information before, between, or after them.
Example: 0xD3 = 2^19 - 6 * 2^15 = 512 KiB - 6 * 32 KiB = 320 KiB
Valid values for dictionary size range from 4 KiB to 512 MiB.
-`Lzma stream'
+'Lzma stream'
The lzma stream, finished by an end of stream marker. Uses default
values for encoder properties. See the lzip manual for a full
description.
-`CRC32 (4 bytes)'
+'CRC32 (4 bytes)'
CRC of the uncompressed original data.
-`Data size (8 bytes)'
+'Data size (8 bytes)'
Size of the uncompressed original data.
-`Member size (8 bytes)'
+'Member size (8 bytes)'
Total size of the member, including header and trailer. This field
acts as a distributed index, allows the verification of stream
integrity, and facilitates safe recovery of undamaged members from
@@ -367,7 +376,7 @@ for all eternity, if not longer.
If you find a bug in plzip, please send electronic mail to
<lzip-bug@nongnu.org>. Include the version number, which you can find
-by running `plzip --version'.
+by running 'plzip --version'.

File: plzip.info, Node: Concept index, Prev: Problems, Up: Top
@@ -391,13 +400,14 @@ Concept index

Tag Table:
-Node: Top223
-Node: Introduction871
-Node: Program design4426
-Node: Invoking plzip5480
-Node: File format10864
-Node: Problems13369
-Node: Concept index13898
+Node: Top221
+Node: Introduction878
+Node: Program design4650
+Node: Invoking plzip5704
+Ref: --data-size6149
+Node: File format11300
+Node: Problems13805
+Node: Concept index14334

End Tag Table