summaryrefslogtreecommitdiff
path: root/Build/source/extra/xz/doc/man
diff options
context:
space:
mode:
authorKarl Berry <karl@freefriends.org>2010-06-13 22:25:43 +0000
committerKarl Berry <karl@freefriends.org>2010-06-13 22:25:43 +0000
commit6019a96432ef8427e402459751109c8b14ec0454 (patch)
tree974dd1260a5003100daa5bb88f279fd477042c93 /Build/source/extra/xz/doc/man
parentf06e0d7e9489163b444e1381a9e670ed1789725d (diff)
xz-4.999.9beta-143-g3e49
git-svn-id: svn://tug.org/texlive/trunk@18955 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Build/source/extra/xz/doc/man')
-rw-r--r--Build/source/extra/xz/doc/man/pdf-a4/lzmainfo-a4.pdfbin4318 -> 4318 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-a4/xz-a4.pdfbin41293 -> 49793 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-a4/xzdec-a4.pdfbin6900 -> 6900 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-a4/xzdiff-a4.pdfbin4241 -> 4241 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-a4/xzgrep-a4.pdfbin4443 -> 4443 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-a4/xzless-a4.pdfbin4274 -> 4274 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-a4/xzmore-a4.pdfbin4212 -> 4212 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-letter/lzmainfo-letter.pdfbin4316 -> 4316 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-letter/xz-letter.pdfbin41272 -> 49760 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-letter/xzdec-letter.pdfbin6895 -> 6895 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-letter/xzdiff-letter.pdfbin4241 -> 4241 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-letter/xzgrep-letter.pdfbin4440 -> 4440 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-letter/xzless-letter.pdfbin4273 -> 4273 bytes
-rw-r--r--Build/source/extra/xz/doc/man/pdf-letter/xzmore-letter.pdfbin4210 -> 4210 bytes
-rw-r--r--Build/source/extra/xz/doc/man/txt/xz.txt345
15 files changed, 287 insertions, 58 deletions
diff --git a/Build/source/extra/xz/doc/man/pdf-a4/lzmainfo-a4.pdf b/Build/source/extra/xz/doc/man/pdf-a4/lzmainfo-a4.pdf
index 4e82bed57cd..997898861a2 100644
--- a/Build/source/extra/xz/doc/man/pdf-a4/lzmainfo-a4.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-a4/lzmainfo-a4.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-a4/xz-a4.pdf b/Build/source/extra/xz/doc/man/pdf-a4/xz-a4.pdf
index 50a9a1a75af..b893db2b190 100644
--- a/Build/source/extra/xz/doc/man/pdf-a4/xz-a4.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-a4/xz-a4.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-a4/xzdec-a4.pdf b/Build/source/extra/xz/doc/man/pdf-a4/xzdec-a4.pdf
index cc58976979e..f79f6076132 100644
--- a/Build/source/extra/xz/doc/man/pdf-a4/xzdec-a4.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-a4/xzdec-a4.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-a4/xzdiff-a4.pdf b/Build/source/extra/xz/doc/man/pdf-a4/xzdiff-a4.pdf
index 13910c684d0..f6c3a7ca0dc 100644
--- a/Build/source/extra/xz/doc/man/pdf-a4/xzdiff-a4.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-a4/xzdiff-a4.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-a4/xzgrep-a4.pdf b/Build/source/extra/xz/doc/man/pdf-a4/xzgrep-a4.pdf
index 9fd5cc278e9..7408a58d466 100644
--- a/Build/source/extra/xz/doc/man/pdf-a4/xzgrep-a4.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-a4/xzgrep-a4.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-a4/xzless-a4.pdf b/Build/source/extra/xz/doc/man/pdf-a4/xzless-a4.pdf
index 2a8f0e69670..96af27715c1 100644
--- a/Build/source/extra/xz/doc/man/pdf-a4/xzless-a4.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-a4/xzless-a4.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-a4/xzmore-a4.pdf b/Build/source/extra/xz/doc/man/pdf-a4/xzmore-a4.pdf
index b43131dd5d0..de444b8e9a1 100644
--- a/Build/source/extra/xz/doc/man/pdf-a4/xzmore-a4.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-a4/xzmore-a4.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-letter/lzmainfo-letter.pdf b/Build/source/extra/xz/doc/man/pdf-letter/lzmainfo-letter.pdf
index feeaad35013..513b8c03fbb 100644
--- a/Build/source/extra/xz/doc/man/pdf-letter/lzmainfo-letter.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-letter/lzmainfo-letter.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-letter/xz-letter.pdf b/Build/source/extra/xz/doc/man/pdf-letter/xz-letter.pdf
index 7c6590edf28..330f6f1d710 100644
--- a/Build/source/extra/xz/doc/man/pdf-letter/xz-letter.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-letter/xz-letter.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-letter/xzdec-letter.pdf b/Build/source/extra/xz/doc/man/pdf-letter/xzdec-letter.pdf
index a8d4b221a50..8476663bcc2 100644
--- a/Build/source/extra/xz/doc/man/pdf-letter/xzdec-letter.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-letter/xzdec-letter.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-letter/xzdiff-letter.pdf b/Build/source/extra/xz/doc/man/pdf-letter/xzdiff-letter.pdf
index 30fd16fc93b..2955ec38ae0 100644
--- a/Build/source/extra/xz/doc/man/pdf-letter/xzdiff-letter.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-letter/xzdiff-letter.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-letter/xzgrep-letter.pdf b/Build/source/extra/xz/doc/man/pdf-letter/xzgrep-letter.pdf
index e192b588e78..494101e7da2 100644
--- a/Build/source/extra/xz/doc/man/pdf-letter/xzgrep-letter.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-letter/xzgrep-letter.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-letter/xzless-letter.pdf b/Build/source/extra/xz/doc/man/pdf-letter/xzless-letter.pdf
index aed468dcc84..02324f6f13c 100644
--- a/Build/source/extra/xz/doc/man/pdf-letter/xzless-letter.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-letter/xzless-letter.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/pdf-letter/xzmore-letter.pdf b/Build/source/extra/xz/doc/man/pdf-letter/xzmore-letter.pdf
index 11c162c0c3c..3bd45d57eea 100644
--- a/Build/source/extra/xz/doc/man/pdf-letter/xzmore-letter.pdf
+++ b/Build/source/extra/xz/doc/man/pdf-letter/xzmore-letter.pdf
Binary files differ
diff --git a/Build/source/extra/xz/doc/man/txt/xz.txt b/Build/source/extra/xz/doc/man/txt/xz.txt
index 6d9c00068d3..5e71d7cca45 100644
--- a/Build/source/extra/xz/doc/man/txt/xz.txt
+++ b/Build/source/extra/xz/doc/man/txt/xz.txt
@@ -121,6 +121,19 @@ DESCRIPTION
--info-memory or near the bottom of the output of --long-help. The
default limit can be overridden with --memory=limit.
+ Concatenation and padding with .xz files
+ It is possible to concatenate .xz files as is. xz will decompress such
+ files as if they were a single .xz file.
+
+ It is possible to insert padding between the concenated parts or after
+ the last part. The padding must be null bytes and the size of the pad-
+ ding must be a multiple of four bytes. This can be useful if the .xz
+ file is stored on a medium that stores file sizes e.g. as 512-byte
+ blocks.
+
+ Concatenation and padding are not allowed with .lzma files or raw
+ streams.
+
OPTIONS
Integer suffixes and special values
In most places where an integer argument is expected, an optional suf-
@@ -158,12 +171,22 @@ OPTIONS
written to standard output.
-l, --list
- View information about the compressed files. No uncompressed
- output is produced, and no files are created or removed. In list
- mode, the program cannot read the compressed data from standard
- input or from other unseekable sources.
-
- This feature has not been implemented yet.
+ List information about compressed files. No uncompressed output
+ is produced, and no files are created or removed. In list mode,
+ the program cannot read the compressed data from standard input
+ or from other unseekable sources.
+
+ The default listing shows basic information about files, one
+ file per line. To get more detailed information, use also the
+ --verbose option. For even more information, use --verbose
+ twice, but note that it may be slow, because getting all the
+ extra information requires many seeks. The width of verbose out-
+ put exceeds 80 characters, so piping the output to e.g. less -S
+ may be convenient if the terminal isn't wide enough.
+
+ The exact output may vary between xz versions and different
+ locales. To get machine-readable output, --robot --list should
+ be used.
Operation modifiers
-k, --keep
@@ -677,17 +700,13 @@ OPTIONS
Print messages in a machine-parsable format. This is intended to
ease writing frontends that want to use xz instead of liblzma,
which may be the case with various scripts. The output with this
- option enabled is meant to be stable across xz releases. Cur-
- rently --robot is implemented only for --info-memory and --ver-
- sion, but the idea is to make it usable for actual compression
- and decompression too.
+ option enabled is meant to be stable across xz releases. See the
+ section ROBOT MODE for details.
--info-memory
Display the current memory usage limit in human-readable format
on a single line, and exit successfully. To see how much RAM xz
- thinks your system has, use --memory=100% --info-memory. To get
- machine-parsable output (memory usage limit as bytes without
- thousand separators), specify --robot before --info-memory.
+ thinks your system has, use --memory=100% --info-memory.
-h, --help
Display a help message describing the most commonly used
@@ -702,6 +721,191 @@ OPTIONS
format. To get machine-parsable output, specify --robot before
--version.
+ROBOT MODE
+ The robot mode is activated with the --robot option. It makes the out-
+ put of xz easier to parse by other programs. Currently --robot is sup-
+ ported only together with --version, --info-memory, and --list. It
+ will be supported for normal compression and decompression in the
+ future.
+
+ Version
+ xz --robot --version will print the version number of xz and liblzma in
+ the following format:
+
+ XZ_VERSION=XYYYZZZS
+ LIBLZMA_VERSION=XYYYZZZS
+
+ X Major version.
+
+ YYY Minor version. Even numbers are stable. Odd numbers are alpha
+ or beta versions.
+
+ ZZZ Patch level for stable releases or just a counter for develop-
+ ment releases.
+
+ S Stability. 0 is alpha, 1 is beta, and 2 is stable. S should be
+ always 2 when YYY is even.
+
+ XYYYZZZS are the same on both lines if xz and liblzma are from the same
+ XZ Utils release.
+
+ Examples: 4.999.9beta is 49990091 and 5.0.0 is 50000002.
+
+ Memory limit information
+ xz --robot --info-memory prints the current memory usage limit as bytes
+ on a single line. To get the total amount of installed RAM, use xz
+ --robot --memory=100% --info-memory.
+
+ List mode
+ xz --robot --list uses tab-separated output. The first column of every
+ line has a string that indicates the type of the information found on
+ that line:
+
+ name This is always the first line when starting to list a file. The
+ second column on the line is the filename.
+
+ file This line contains overall information about the .xz file. This
+ line is always printed after the name line.
+
+ stream This line type is used only when --verbose was specified. There
+ are as many stream lines as there are streams in the .xz file.
+
+ block This line type is used only when --verbose was specified. There
+ are as many block lines as there are blocks in the .xz file. The
+ block lines are shown after all the stream lines; different line
+ types are not interleaved.
+
+ summary
+ This line type is used only when --verbose was specified twice.
+ This line is printed after all block lines. Like the file line,
+ the summary line contains overall information about the .xz
+ file.
+
+ totals This line is always the very last line of the list output. It
+ shows the total counts and sizes.
+
+ The columns of the file lines:
+
+ 2. Number of streams in the file
+
+ 3. Total number of blocks in the stream(s)
+
+ 4. Compressed size of the file
+
+ 5. Uncompressed size of the file
+
+ 6. Compression ratio, for example 0.123. If ratio is over
+ 9.999, three dashes (---) are displayed instead of the
+ ratio.
+
+ 7. Comma-separated list of integrity check names. The following
+ strings are used for the known check types: None, CRC32,
+ CRC64, and SHA-256. For unknown check types, Unknown-N is
+ used, where N is the Check ID as a decimal number (one or
+ two digits).
+
+ 8. Total size of stream padding in the file
+
+ The columns of the stream lines:
+
+ 2. Stream number (the first stream is 1)
+
+ 3. Number of blocks in the stream
+
+ 4. Compressed start offset
+
+ 5. Uncompressed start offset
+
+ 6. Compressed size (does not include stream padding)
+
+ 7. Uncompressed size
+
+ 8. Compression ratio
+
+ 9. Name of the integrity check
+
+ 10. Size of stream padding
+
+ The columns of the block lines:
+
+ 2. Number of the stream containing this block
+
+ 3. Block number relative to the beginning of the stream (the
+ first block is 1)
+
+ 4. Block number relative to the beginning of the file
+
+ 5. Compressed start offset relative to the beginning of the
+ file
+
+ 6. Uncompressed start offset relative to the beginning of the
+ file
+
+ 7. Total compressed size of the block (includes headers)
+
+ 8. Uncompressed size
+
+ 9. Compression ratio
+
+ 10. Name of the integrity check
+
+ If --verbose was specified twice, additional columns are included on
+ the block lines. These are not displayed with a single --verbose,
+ because getting this information requires many seeks and can thus be
+ slow:
+
+ 11. Value of the integrity check in hexadecimal
+
+ 12. Block header size
+
+ 13. Block flags: c indicates that compressed size is present,
+ and u indicates that uncompressed size is present. If the
+ flag is not set, a dash (-) is shown instead to keep the
+ string length fixed. New flags may be added to the end of
+ the string in the future.
+
+ 14. Size of the actual compressed data in the block (this
+ excludes the block header, block padding, and check fields)
+
+ 15. Amount of memory (as bytes) required to decompress this
+ block with this xz version
+
+ 16. Filter chain. Note that most of the options used at compres-
+ sion time cannot be known, because only the options that are
+ needed for decompression are stored in the .xz headers.
+
+ The columns of the totals line:
+
+ 2. Number of streams
+
+ 3. Number of blocks
+
+ 4. Compressed size
+
+ 5. Uncompressed size
+
+ 6. Average compression ratio
+
+ 7. Comma-separated list of integrity check names that were
+ present in the files
+
+ 8. Stream padding size
+
+ 9. Number of files. This is here to keep the order of the ear-
+ lier columns the same as on file lines.
+
+ If --verbose was specified twice, additional columns are included on
+ the totals line:
+
+ 10. Maximum amount of memory (as bytes) required to decompress
+ the files with this xz version
+
+ 11. yes or no indicating if all block headers have both com-
+ pressed size and uncompressed size stored in them
+
+ Future versions may add new line types and new columns can be added to
+ the existing line types, but the existing columns won't be changed.
+
EXIT STATUS
0 All is good.
@@ -714,23 +918,23 @@ EXIT STATUS
the exit status.
ENVIRONMENT
- XZ_OPT A space-separated list of options is parsed from XZ_OPT before
- parsing the options given on the command line. Note that only
- options are parsed from XZ_OPT; all non-options are silently
- ignored. Parsing is done with getopt_long(3) which is used also
+ XZ_OPT A space-separated list of options is parsed from XZ_OPT before
+ parsing the options given on the command line. Note that only
+ options are parsed from XZ_OPT; all non-options are silently
+ ignored. Parsing is done with getopt_long(3) which is used also
for the command line arguments.
LZMA UTILS COMPATIBILITY
- The command line syntax of xz is practically a superset of lzma,
+ The command line syntax of xz is practically a superset of lzma,
unlzma, and lzcat as found from LZMA Utils 4.32.x. In most cases, it is
- possible to replace LZMA Utils with XZ Utils without breaking existing
- scripts. There are some incompatibilities though, which may sometimes
+ possible to replace LZMA Utils with XZ Utils without breaking existing
+ scripts. There are some incompatibilities though, which may sometimes
cause problems.
Compression preset levels
- The numbering of the compression level presets is not identical in xz
- and LZMA Utils. The most important difference is how dictionary sizes
- are mapped to different presets. Dictionary size is roughly equal to
+ The numbering of the compression level presets is not identical in xz
+ and LZMA Utils. The most important difference is how dictionary sizes
+ are mapped to different presets. Dictionary size is roughly equal to
the decompressor memory usage.
Level xz LZMA Utils
@@ -745,7 +949,7 @@ LZMA UTILS COMPATIBILITY
-9 64 MiB 32 MiB
The dictionary size differences affect the compressor memory usage too,
- but there are some other differences between LZMA Utils and XZ Utils,
+ but there are some other differences between LZMA Utils and XZ Utils,
which make the difference even bigger:
Level xz LZMA Utils 4.32.x
@@ -759,81 +963,106 @@ LZMA UTILS COMPATIBILITY
-8 370 MiB 159 MiB
-9 674 MiB 311 MiB
- The default preset level in LZMA Utils is -7 while in XZ Utils it is
+ The default preset level in LZMA Utils is -7 while in XZ Utils it is
-6, so both use 8 MiB dictionary by default.
Streamed vs. non-streamed .lzma files
- Uncompressed size of the file can be stored in the .lzma header. LZMA
- Utils does that when compressing regular files. The alternative is to
+ Uncompressed size of the file can be stored in the .lzma header. LZMA
+ Utils does that when compressing regular files. The alternative is to
mark that uncompressed size is unknown and use end of payload marker to
- indicate where the decompressor should stop. LZMA Utils uses this
- method when uncompressed size isn't known, which is the case for exam-
+ indicate where the decompressor should stop. LZMA Utils uses this
+ method when uncompressed size isn't known, which is the case for exam-
ple in pipes.
- xz supports decompressing .lzma files with or without end of payload
- marker, but all .lzma files created by xz will use end of payload
- marker and have uncompressed size marked as unknown in the .lzma
- header. This may be a problem in some (uncommon) situations. For exam-
- ple, a .lzma decompressor in an embedded device might work only with
- files that have known uncompressed size. If you hit this problem, you
- need to use LZMA Utils or LZMA SDK to create .lzma files with known
+ xz supports decompressing .lzma files with or without end of payload
+ marker, but all .lzma files created by xz will use end of payload
+ marker and have uncompressed size marked as unknown in the .lzma
+ header. This may be a problem in some (uncommon) situations. For exam-
+ ple, a .lzma decompressor in an embedded device might work only with
+ files that have known uncompressed size. If you hit this problem, you
+ need to use LZMA Utils or LZMA SDK to create .lzma files with known
uncompressed size.
Unsupported .lzma files
- The .lzma format allows lc values up to 8, and lp values up to 4. LZMA
+ The .lzma format allows lc values up to 8, and lp values up to 4. LZMA
Utils can decompress files with any lc and lp, but always creates files
- with lc=3 and lp=0. Creating files with other lc and lp is possible
+ with lc=3 and lp=0. Creating files with other lc and lp is possible
with xz and with LZMA SDK.
The implementation of the LZMA1 filter in liblzma requires that the sum
- of lc and lp must not exceed 4. Thus, .lzma files which exceed this
+ of lc and lp must not exceed 4. Thus, .lzma files which exceed this
limitation, cannot be decompressed with xz.
- LZMA Utils creates only .lzma files which have dictionary size of 2^n
- (a power of 2), but accepts files with any dictionary size. liblzma
- accepts only .lzma files which have dictionary size of 2^n or 2^n +
- 2^(n-1). This is to decrease false positives when detecting .lzma
+ LZMA Utils creates only .lzma files which have dictionary size of 2^n
+ (a power of 2), but accepts files with any dictionary size. liblzma
+ accepts only .lzma files which have dictionary size of 2^n or 2^n +
+ 2^(n-1). This is to decrease false positives when detecting .lzma
files.
These limitations shouldn't be a problem in practice, since practically
- all .lzma files have been compressed with settings that liblzma will
+ all .lzma files have been compressed with settings that liblzma will
accept.
Trailing garbage
- When decompressing, LZMA Utils silently ignore everything after the
- first .lzma stream. In most situations, this is a bug. This also means
+ When decompressing, LZMA Utils silently ignore everything after the
+ first .lzma stream. In most situations, this is a bug. This also means
that LZMA Utils don't support decompressing concatenated .lzma files.
- If there is data left after the first .lzma stream, xz considers the
- file to be corrupt. This may break obscure scripts which have assumed
+ If there is data left after the first .lzma stream, xz considers the
+ file to be corrupt. This may break obscure scripts which have assumed
that trailing garbage is ignored.
NOTES
Compressed output may vary
- The exact compressed output produced from the same uncompressed input
+ The exact compressed output produced from the same uncompressed input
file may vary between XZ Utils versions even if compression options are
identical. This is because the encoder can be improved (faster or bet-
ter compression) without affecting the file format. The output can vary
- even between different builds of the same XZ Utils version, if differ-
+ even between different builds of the same XZ Utils version, if differ-
ent build options are used.
- The above means that implementing --rsyncable to create rsyncable .xz
- files is not going to happen without freezing a part of the encoder
+ The above means that implementing --rsyncable to create rsyncable .xz
+ files is not going to happen without freezing a part of the encoder
implementation, which can then be used with --rsyncable.
Embedded .xz decompressors
Embedded .xz decompressor implementations like XZ Embedded don't neces-
- sarily support files created with check types other than none and
- crc32. Since the default is --check=crc64, you must use --check=none
+ sarily support files created with check types other than none and
+ crc32. Since the default is --check=crc64, you must use --check=none
or --check=crc32 when creating files for embedded systems.
- Outside embedded systems, all .xz format decompressors support all the
- check types, or at least are able to decompress the file without veri-
+ Outside embedded systems, all .xz format decompressors support all the
+ check types, or at least are able to decompress the file without veri-
fying the integrity check if the particular check is not supported.
- XZ Embedded supports BCJ filters, but only with the default start off-
+ XZ Embedded supports BCJ filters, but only with the default start off-
set.
+EXAMPLES
+ Basics
+ A mix of compressed and uncompressed files can be decompressed to stan-
+ dard output with a single command:
+
+ xz -dcf a.txt b.txt.xz c.txt d.txt.xz > abcd.txt
+
+ Parallel compression of many files
+ On GNU and *BSD, find(1) and xargs(1) can be used to parallellize com-
+ pression of many files:
+
+ find . -type f \! -name '*.xz' -print0 | xargs -0r -P4 -n16 xz
+
+ The -P option sets the number of parallel xz processes. The best value
+ for the -n option depends on how many files there are to be compressed.
+ If there are only a couple of files, the value should probably be 1;
+ with tens of thousands of files, 100 or even more may be appropriate to
+ reduce the number of xz processes that xargs(1) will eventually create.
+
+ Robot mode examples
+ Calculating how many bytes have been saved in total after compressing
+ multiple files:
+
+ xz --robot --list *.xz | awk '/^totals/{print $5-$4}'
+
SEE ALSO
xzdec(1), gzip(1), bzip2(1)
@@ -843,4 +1072,4 @@ SEE ALSO
-Tukaani 2010-03-07 XZ(1)
+Tukaani 2010-06-01 XZ(1)