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-rw-r--r--doc/zutils.info366
1 files changed, 228 insertions, 138 deletions
diff --git a/doc/zutils.info b/doc/zutils.info
index 9a9ca05..ea12cc3 100644
--- a/doc/zutils.info
+++ b/doc/zutils.info
@@ -11,13 +11,13 @@ File: zutils.info, Node: Top, Next: Introduction, Up: (dir)
Zutils Manual
*************
-This manual is for Zutils (version 1.12-pre2, 12 April 2022).
+This manual is for Zutils (version 1.12-rc1, 5 December 2022).
* Menu:
* Introduction:: Purpose and features of zutils
* Common options:: Options common to all utilities
-* The zutilsrc file:: The zutils configuration file
+* Configuration:: The configuration file zutils.conf
* Zcat:: Concatenating compressed files
* Zcmp:: Comparing compressed files byte by byte
* Zdiff:: Comparing compressed files line by line
@@ -43,20 +43,22 @@ Zutils is a collection of utilities able to process any combination of
compressed and uncompressed files transparently. If any file given,
including standard input, is compressed, its decompressed content is used.
Compressed files are decompressed on the fly; no temporary files are
-created.
+created. Data format is detected by its magic bytes, not by the file name
+extension.
These utilities are not wrapper scripts but safer and more efficient C++
programs. In particular the option '--recursive' is very efficient in those
utilities supporting it.
-The utilities provided are zcat, zcmp, zdiff, zgrep, ztest, and zupdate.
+The utilities provided are 'zcat', 'zcmp', 'zdiff', 'zgrep', 'ztest', and
+'zupdate'.
The formats supported are bzip2, gzip, lzip, xz, and zstd.
Zutils uses external compressors. The compressor to be used for each format
is configurable at runtime.
- zcat, zcmp, zdiff, and zgrep are improved replacements for the shell
-scripts provided by GNU gzip. ztest is unique to zutils. zupdate is similar
-to gzip's znew.
+ 'zcat', 'zcmp', 'zdiff', and 'zgrep' are improved replacements for the
+shell scripts provided by GNU gzip. 'ztest' is unique to zutils. 'zupdate'
+is similar to gzip's znew.
NOTE: Bzip2 and lzip provide well-defined values of exit status, which
makes them safe to use with zutils. Gzip and xz may return ambiguous warning
@@ -94,7 +96,7 @@ Z zettabyte (10^21) | Zi zebibyte (2^70)
Y yottabyte (10^24) | Yi yobibyte (2^80)

-File: zutils.info, Node: Common options, Next: The zutilsrc file, Prev: Introduction, Up: Top
+File: zutils.info, Node: Common options, Next: Configuration, Prev: Introduction, Up: Top
2 Common options
****************
@@ -106,14 +108,17 @@ here. *Note Argument syntax: (arg_parser)Argument syntax.
'-h'
'--help'
Print an informative help message describing the options and exit.
- zgrep only supports the '--help' form of this option.
+ 'zgrep' only supports the '--help' form of this option.
'-V'
'--version'
Print the version number on the standard output and exit. This version
- number should be included in all bug reports. In verbose mode, zdiff
- and zgrep print also the version of the diff or grep program used
- respectively.
+ number should be included in all bug reports. In verbose mode, 'zdiff'
+ and 'zgrep' print also the version of the diff or grep program used
+ respectively. At verbosity level 1 (2 for 'zdiff' and 'zgrep') or
+ higher, print also the versions of the compressors used (perhaps
+ limited by option '--format'). (The compressors used must support the
+ option '-V' for this to work).
'-M FORMAT_LIST'
'--format=FORMAT_LIST'
@@ -138,20 +143,19 @@ here. *Note Argument syntax: (arg_parser)Argument syntax.
'-N'
'--no-rcfile'
- Don't read the runtime configuration file 'zutilsrc'.
+ Don't read the runtime configuration file 'zutils.conf'.
'--bz2=COMMAND'
'--gz=COMMAND'
'--lz=COMMAND'
'--xz=COMMAND'
'--zst=COMMAND'
- Set program to be used as (de)compressor for the corresponding format.
+ Set program to be used as decompressor for the corresponding format.
COMMAND may include arguments. For example '--lz='plzip --threads=2''.
- The program set with '--lz' is used for both compression and
- decompression. The others are used only for decompression. The name of
- the program can't begin with '-'. These options override the values
- set in 'zutilsrc'. The compression program used must meet three
- requirements:
+ 'zupdate' uses '--lz' for compression, not for decompression (*note
+ lz-compressor::). The name of the program can't begin with '-'. These
+ options override the values set in 'zutils.conf'. The compression
+ program used must meet three requirements:
1. When called with the option '-d' and without file names, it must
read compressed data from the standard input and produce
@@ -165,21 +169,23 @@ here. *Note Argument syntax: (arg_parser)Argument syntax.

-File: zutils.info, Node: The zutilsrc file, Next: Zcat, Prev: Common options, Up: Top
+File: zutils.info, Node: Configuration, Next: Zcat, Prev: Common options, Up: Top
-3 The zutils configuration file 'zutilsrc'
-******************************************
+3 The configuration file 'zutils.conf'
+**************************************
-'zutilsrc' is the runtime configuration file for zutils. In it you may
+'zutils.conf' is the runtime configuration file for zutils. In it you may
define the compressor name and options to be used for each format.
-'zutilsrc' is optional; you don't need to install it in order to run zutils.
+'zutils.conf' is optional; you don't need to install it in order to run
+zutils.
The compressors specified in the command line override those specified
-in 'zutilsrc'.
+in 'zutils.conf'.
- You may copy the system 'zutilsrc' file '${sysconfdir}/zutilsrc' to
-'$HOME/.zutilsrc' and customize these options as you like. The file syntax
-is fairly obvious (and there are further instructions in it):
+ You may copy the system 'zutils.conf' file '${sysconfdir}/zutils.conf'
+to '$XDG_CONFIG_HOME/zutils.conf' and customize these options as you like.
+('XDG_CONFIG_HOME' defaults to '$HOME/.config'). The file syntax is fairly
+obvious (and there are further instructions in it):
1. Any line beginning with '#' is a comment line.
@@ -189,17 +195,17 @@ is fairly obvious (and there are further instructions in it):
where <format> is one of 'bz2', 'gz', 'lz', 'xz', or 'zst'.

-File: zutils.info, Node: Zcat, Next: Zcmp, Prev: The zutilsrc file, Up: Top
+File: zutils.info, Node: Zcat, Next: Zcmp, Prev: Configuration, Up: Top
4 Zcat
******
-zcat copies each FILE argument to standard output in sequence. If any file
-given is compressed, its decompressed content is copied. If a file given
-does not exist, and its name does not end with one of the known extensions,
-zcat tries the compressed file names corresponding to the formats
-supported. If a file fails to decompress, zcat continues copying the rest
-of the files.
+'zcat' copies each FILE argument to standard output in sequence. If any
+file given is compressed, its decompressed content is copied. If a file
+given does not exist, and its name does not end with one of the known
+extensions, 'zcat' tries the compressed file names corresponding to the
+formats supported. If a file fails to decompress, 'zcat' continues copying
+the rest of the files.
If a file is specified as '-', data are read from standard input,
decompressed if needed, and sent to standard output. Data read from
@@ -209,13 +215,13 @@ same compressed format.
If no files are specified, recursive searches examine the current working
directory, and nonrecursive searches read standard input.
- The format for running zcat is:
+ The format for running 'zcat' is:
zcat [OPTIONS] [FILES]
Exit status is 0 if no errors occurred, 1 otherwise.
- zcat supports the following options:
+ 'zcat' supports the following options:
'-A'
'--show-all'
@@ -240,10 +246,10 @@ Exit status is 0 if no errors occurred, 1 otherwise.
'-O FORMAT'
'--force-format=FORMAT'
Force the compressed format given. Valid values for FORMAT are 'bz2',
- 'gz', 'lz', 'xz', and 'zst'. If this option is used, the files are
- passed to the corresponding decompressor without verifying their
- format, and the exact file name must be given. Other names won't be
- tried.
+ 'gz', 'lz', 'xz', 'zst', and 'un' for 'uncompressed'. If this option
+ is used, the files are passed to the corresponding decompressor (or
+ transmitted unmodified) without verifying their format, and the exact
+ file name must be given. Other names won't be tried.
'-q'
'--quiet'
@@ -278,7 +284,8 @@ Exit status is 0 if no errors occurred, 1 otherwise.
stands for "meta").
'--verbose'
- Verbose mode. Show error messages.
+ Verbose mode. Show error messages. Repeating it increases the verbosity
+ level. *Note version::.

@@ -287,19 +294,19 @@ File: zutils.info, Node: Zcmp, Next: Zdiff, Prev: Zcat, Up: Top
5 Zcmp
******
-zcmp compares two files and, if they differ, writes to standard output the
-first byte and line number where they differ. Bytes and lines are numbered
-starting with 1. A hyphen '-' used as a FILE argument means standard input.
-If any file given is compressed, its decompressed content is used.
-Compressed files are decompressed on the fly; no temporary files are
-created.
+'zcmp' compares two files and, if they differ, writes to standard output
+the first byte and line number where they differ. Bytes and lines are
+numbered starting with 1. A hyphen '-' used as a FILE argument means
+standard input. If any file given is compressed, its decompressed content
+is used. Compressed files are decompressed on the fly; no temporary files
+are created.
- The format for running zcmp is:
+ The format for running 'zcmp' is:
zcmp [OPTIONS] FILE1 [FILE2]
This compares FILE1 to FILE2. The standard input is used only if FILE1 or
-FILE2 refers to standard input. If FILE2 is omitted zcmp tries the
+FILE2 refers to standard input. If FILE2 is omitted 'zcmp' tries the
following:
- If FILE1 is compressed, compares its decompressed contents with the
@@ -312,13 +319,19 @@ following:
An exit status of 0 means no differences were found, 1 means some
differences were found, and 2 means trouble.
- zcmp supports the following options:
+ 'zcmp' supports the following options:
'-b'
'--print-bytes'
- Print the differing bytes. Print control bytes as a '^' followed by a
- letter, and precede bytes larger than 127 with 'M-' (which stands for
- "meta").
+ Print the values of the differing bytes (in octal by default) followed
+ by the bytes themselves in printable form. Print control bytes as a '^'
+ followed by a letter, and precede bytes larger than 127 with 'M-'
+ (which stands for "meta").
+
+'-H'
+'--hexadecimal'
+ Print the values of the differing bytes in hexadecimal instead of
+ octal.
'-i SIZE'
'--ignore-initial=SIZE'
@@ -328,11 +341,9 @@ differences were found, and 2 means trouble.
first input file and the first SIZE2 bytes of the second input file.
'-l'
-'-v'
'--list'
-'--verbose'
- Print the byte numbers (in decimal) and values (in octal) of all
- differing bytes.
+ Print the byte numbers (in decimal) and values (in octal by default)
+ of all differing bytes. Bytes are numbered starting with 1.
'-n COUNT'
'--bytes=COUNT'
@@ -342,19 +353,50 @@ differences were found, and 2 means trouble.
'--force-format=[FORMAT1][,FORMAT2]'
Force the compressed formats given. Any of FORMAT1 or FORMAT2 may be
omitted and the corresponding format will be automatically detected.
- Valid values for FORMAT are 'bz2', 'gz', 'lz', 'xz', and 'zst'. If at
- least one format is specified with this option, the file is passed to
- the corresponding decompressor without verifying its format, and the
- exact file names of both FILE1 and FILE2 must be given. Other names
- won't be tried.
+ Valid values for FORMAT are 'bz2', 'gz', 'lz', 'xz', 'zst', and 'un'
+ for 'uncompressed'. If at least one format is specified with this
+ option, the file is passed to the corresponding decompressor (or
+ transmitted unmodified) without verifying its format, and the exact
+ file names of both FILE1 and FILE2 must be given. Other names won't be
+ tried.
'-q'
-'-s'
'--quiet'
'--silent'
- Don't print anything; only return an exit status indicating whether the
- files differ.
+ Suppress diagnostics written to standard error, even the
+ 'EOF on <name_of_shorter_file>' diagnostic. Byte differences are still
+ written to standard output. ('-q' produces no output except byte
+ differences).
+
+'-s'
+'--script'
+ Write nothing to standard output or standard error when files differ,
+ not even the 'EOF on <name_of_shorter_file>' diagnostic; indicate
+ differing files through exit status only. Diagnostic messages are still
+ written to standard error when an error is encountered. ('-s' produces
+ no output except error messages).
+'-v'
+'--verbose'
+ Verbose mode. Undoes the effect of '--quiet'. Further -v's increase
+ the verbosity level. *Note version::.
+
+
+ Byte counts given as arguments to options may be expressed in decimal,
+hexadecimal, or octal (using the same syntax as integer constants in C++),
+and may be followed by a multiplier and an optional 'B' for "byte".
+
+ Table of SI and binary prefixes (unit multipliers):
+
+Prefix Value | Prefix Value
+k kilobyte (10^3 = 1000) | Ki kibibyte (2^10 = 1024)
+M megabyte (10^6) | Mi mebibyte (2^20)
+G gigabyte (10^9) | Gi gibibyte (2^30)
+T terabyte (10^12) | Ti tebibyte (2^40)
+P petabyte (10^15) | Pi pebibyte (2^50)
+E exabyte (10^18) | Ei exbibyte (2^60)
+Z zettabyte (10^21) | Zi zebibyte (2^70)
+Y yottabyte (10^24) | Yi yobibyte (2^80)

File: zutils.info, Node: Zdiff, Next: Zgrep, Prev: Zcmp, Up: Top
@@ -362,19 +404,19 @@ File: zutils.info, Node: Zdiff, Next: Zgrep, Prev: Zcmp, Up: Top
6 Zdiff
*******
-zdiff compares two files and, if they differ, writes to standard output the
-differences line by line. A hyphen '-' used as a FILE argument means
+'zdiff' compares two files and, if they differ, writes to standard output
+the differences line by line. A hyphen '-' used as a FILE argument means
standard input. If any file given is compressed, its decompressed content
-is used. zdiff is a front end to the program diff and has the limitation
+is used. 'zdiff' is a front end to the program diff and has the limitation
that messages from diff refer to temporary file names instead of those
specified.
- The format for running zdiff is:
+ The format for running 'zdiff' is:
zdiff [OPTIONS] FILE1 [FILE2]
This compares FILE1 to FILE2. The standard input is used only if FILE1 or
-FILE2 refers to standard input. If FILE2 is omitted zdiff tries the
+FILE2 refers to standard input. If FILE2 is omitted 'zdiff' tries the
following:
- If FILE1 is compressed, compares its decompressed contents with the
@@ -387,8 +429,8 @@ following:
An exit status of 0 means no differences were found, 1 means some
differences were found, and 2 means trouble.
- zdiff supports the following options (some options only work if the diff
-program used supports them):
+ 'zdiff' supports the following options (some options only work if the
+diff program used supports them):
'-a'
'--text'
@@ -425,11 +467,12 @@ program used supports them):
'--force-format=[FORMAT1][,FORMAT2]'
Force the compressed formats given. Any of FORMAT1 or FORMAT2 may be
omitted and the corresponding format will be automatically detected.
- Valid values for FORMAT are 'bz2', 'gz', 'lz', 'xz', and 'zst'. If at
- least one format is specified with this option, the file is passed to
- the corresponding decompressor without verifying its format, and the
- exact file names of both FILE1 and FILE2 must be given. Other names
- won't be tried.
+ Valid values for FORMAT are 'bz2', 'gz', 'lz', 'xz', 'zst', and 'un'
+ for 'uncompressed'. If at least one format is specified with this
+ option, the file is passed to the corresponding decompressor (or
+ transmitted unmodified) without verifying its format, and the exact
+ file names of both FILE1 and FILE2 must be given. Other names won't be
+ tried.
'-p'
'--show-c-function'
@@ -461,7 +504,8 @@ program used supports them):
'-v'
'--verbose'
When specified before '--version', print the version of the diff
- program used.
+ program used. Further -v's increase the verbosity level. *Note
+ version::.
'-w'
'--ignore-all-space'
@@ -483,12 +527,13 @@ File: zutils.info, Node: Zgrep, Next: Ztest, Prev: Zdiff, Up: Top
7 Zgrep
*******
-zgrep is a front end to the program grep that allows transparent search on
-any combination of compressed and uncompressed files. If any file given is
-compressed, its decompressed content is used. If a file given does not
-exist, and its name does not end with one of the known extensions, zgrep
+'zgrep' is a front end to the program grep that allows transparent search
+on any combination of compressed and uncompressed files. If any file given
+is compressed, its decompressed content is used. If a file given does not
+exist, and its name does not end with one of the known extensions, 'zgrep'
tries the compressed file names corresponding to the formats supported. If
-a file fails to decompress, zgrep continues searching the rest of the files.
+a file fails to decompress, 'zgrep' continues searching the rest of the
+files.
If a file is specified as '-', data are read from standard input,
decompressed if needed, and fed to grep. Data read from standard input must
@@ -497,16 +542,23 @@ be of the same type; all uncompressed or all in the same compressed format.
If no files are specified, recursive searches examine the current working
directory, and nonrecursive searches read standard input.
- The format for running zgrep is:
+ For efficiency reasons, 'zgrep' does not always read all its input. For
+example, the shell command 'base64 -d foo | zgrep -q X' can cause 'zgrep'
+to exit immediately after reading a line containing 'X', without bothering
+to read the rest of its input data. This in turn can cause base64 to exit
+with a nonzero status because base64 cannot write to its output pipe after
+'zgrep' exits.
+
+ The format for running 'zgrep' is:
zgrep [OPTIONS] PATTERN [FILES]
An exit status of 0 means at least one match was found, 1 means no matches
were found, and 2 means trouble.
- zgrep supports the following options (Some options only work if the grep
-program used supports them. Options -h, -H, -r, -R, and -Z are managed by
-zgrep and not passed to grep):
+ 'zgrep' supports the following options (Some options only work if the
+grep program used supports them. Options -h, -H, -r, -R, and -Z are managed
+by 'zgrep' and not passed to grep):
'-a'
'--text'
@@ -577,11 +629,13 @@ zgrep and not passed to grep):
'-l'
'--files-with-matches'
- Only print names of files containing at least one match.
+ Only print names of files containing at least one match. Stop reading
+ each file on the first match.
'-L'
'--files-without-match'
- Only print names of files not containing any matches.
+ Only print names of files not containing any matches. Stop reading
+ each file on the first match.
Note: option -L fails (prints wrong results, returns wrong status, and
even hangs) when using GNU grep versions 3.2 to 3.4 inclusive because
of a wrong change in the exit status of grep, which was reverted in
@@ -609,10 +663,10 @@ zgrep and not passed to grep):
'-O FORMAT'
'--force-format=FORMAT'
Force the compressed format given. Valid values for FORMAT are 'bz2',
- 'gz', 'lz', 'xz', and 'zst'. If this option is used, the files are
- passed to the corresponding decompressor without verifying their
- format, and the exact file name must be given. Other names won't be
- tried.
+ 'gz', 'lz', 'xz', 'zst', and 'un' for 'uncompressed'. If this option
+ is used, the files are passed to the corresponding decompressor (or
+ transmitted unmodified) without verifying their format, and the exact
+ file name must be given. Other names won't be tried.
'-P'
'--perl-regexp'
@@ -655,7 +709,8 @@ zgrep and not passed to grep):
'--verbose'
Verbose mode. Show error messages. When specified before '--version',
- print the version of the grep program used.
+ print the version of the grep program used. Repeating it increases the
+ verbosity level. *Note version::.
'-w'
'--word-regexp'
@@ -680,14 +735,16 @@ File: zutils.info, Node: Ztest, Next: Zupdate, Prev: Zgrep, Up: Top
8 Ztest
*******
-ztest verifies the integrity of the compressed files specified.
-Uncompressed files are ignored. If a file is specified as '-', the
-integrity of compressed data read from standard input is verified. Data
-read from standard input must be all in the same compressed format. If a
-file fails to decompress, does not exist, can't be opened, or is a
-terminal, ztest continues verifying the rest of the files. A final
-diagnostic is shown at verbosity level 1 or higher if any file fails the
-test when testing multiple files.
+'ztest' verifies the integrity of the compressed files specified. It also
+warns if an uncompressed file has a compressed file name extension, or if a
+compressed file has a wrong compressed extension. Uncompressed files are
+otherwise ignored. If a file is specified as '-', the integrity of
+compressed data read from standard input is verified. Data read from
+standard input must be all in the same compressed format. If a file fails to
+decompress, does not exist, can't be opened, or is a terminal, 'ztest'
+continues verifying the rest of the files. A final diagnostic is shown at
+verbosity level 1 or higher if any file fails the test when testing multiple
+files.
If no files are specified, recursive searches examine the current working
directory, and nonrecursive searches read standard input.
@@ -703,15 +760,16 @@ of the xz format specification allows xz decompressors to produce garbage
output without issuing any warning. Therefore, xz files can't always be
verified as reliably as files in the other formats can.
- The format for running ztest is:
+ The format for running 'ztest' is:
ztest [OPTIONS] [FILES]
-The exit status is 0 if all compressed files verify OK, 1 if environmental
-problems (file not found, invalid flags, I/O errors, etc), 2 if any
-compressed file is corrupt or invalid.
+Exit status is 0 if all compressed files verify OK, 1 if environmental
+problems (file not found, invalid command line options, I/O errors, etc), 2
+if any compressed file is corrupt or invalid, or if any file has an
+incorrect file name extension.
- ztest supports the following options:
+ 'ztest' supports the following options:
'-O FORMAT'
'--force-format=FORMAT'
@@ -738,8 +796,8 @@ compressed file is corrupt or invalid.
'-v'
'--verbose'
- Verbose mode. Show the verify status for each file processed.
- Further -v's increase the verbosity level.
+ Verbose mode. Show the verify status for each file processed. Further
+ -v's increase the verbosity level. *Note version::.

@@ -748,12 +806,12 @@ File: zutils.info, Node: Zupdate, Next: Problems, Prev: Ztest, Up: Top
9 Zupdate
*********
-zupdate recompresses files from bzip2, gzip, xz, and zstd formats to lzip
+'zupdate' recompresses files from bzip2, gzip, xz, and zstd formats to lzip
format. Each original is compared with the new file and then deleted. Only
regular files with standard file name extensions are recompressed, other
files are ignored. Compressed files are decompressed and then recompressed
on the fly; no temporary files are created. If an error happens while
-recompressing a file, zupdate exits immediately without recompressing the
+recompressing a file, 'zupdate' exits immediately without recompressing the
rest of the files. The lzip format is chosen as destination because it is
the most appropriate for long-term data archiving.
@@ -763,7 +821,7 @@ directory, and nonrecursive searches do nothing.
If the lzip compressed version of a file already exists, the file is
skipped unless the option '--force' is given. In this case, if the
comparison with the existing lzip version fails, an error is returned and
-the original file is not deleted. The operation of zupdate is meant to be
+the original file is not deleted. The operation of 'zupdate' is meant to be
safe and not cause any data loss. Therefore, existing lzip compressed files
are never overwritten nor deleted.
@@ -787,23 +845,40 @@ recompressing Slackware packages, for example.
If the decompressor for the xz or zstd formats is not found, the
corresponding files are ignored.
- Recompressing a file is much like copying or moving it. Therefore zupdate
-preserves the access and modification dates, permissions, and, if you have
-appropriate privileges, 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).
+ Recompressing a file is much like copying or moving it. Therefore
+'zupdate' preserves the access and modification dates, permissions, and, if
+you have appropriate privileges, 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).
- The format for running zupdate is:
+ The format for running 'zupdate' is:
zupdate [OPTIONS] [FILES]
Exit status is 0 if all the compressed files were successfully recompressed
(if needed), compared, and deleted (if requested). 1 if a non-fatal error
occurred (file not found or not regular, or has invalid format, or can't be
-deleted). 2 if a fatal error occurred (compressor can't be run, or
-comparison fails).
-
- zupdate supports the following options:
+deleted). 2 if a fatal error occurred (invalid command line options,
+compressor can't be run, or comparison fails).
+
+ 'zupdate' supports the following options:
+
+'-d DIR'
+'--destdir=DIR'
+ Write recompressed files to another directory, using DIR as base
+ directory, instead of writing them in the same directory as the
+ original files. In recursive mode, this is done by replacing each
+ directory specified in the command line with DIR to produce the
+ recompressed file names. For example, 'zupdate -r -d DIR ../a'
+ recompresses a file named '../a/b/c.gz' to 'DIR/b/c.lz'. Regular files
+ specified in the command line are recompressed directly into DIR. For
+ example, 'zupdate -d DIR ../a/b/c.gz' writes the recompressed file to
+ 'DIR/c.lz'.
+
+ This option allows recompressing files from a read-only file system to
+ another place without the need to copy or link them to the destination
+ directory first. (Remember to use option '--keep' when recompressing
+ read-only files to avoid warnings about files that can't be deleted).
'-e'
'--expand-extensions'
@@ -851,13 +926,26 @@ comparison fails).
'-v'
'--verbose'
Verbose mode. Show the files being processed. A second '-v' also shows
- the files being ignored.
+ the files being ignored and increases the verbosity level. *Note
+ version::.
'-0 .. -9'
- Set the compression level of lzip. By default zupdate passes '-9' to
+ Set the compression level of lzip. By default 'zupdate' passes '-9' to
lzip. Custom compression options can be passed to lzip with the option
'--lz'. For example '--lz='lzip -9 -s64MiB''.
+'--lz=COMMAND'
+ Set compression command. COMMAND may include arguments. For example
+ '--lz='plzip --threads=2''. The name of the program can't begin with
+ '-'. This option overrides the value set in 'zutils.conf'. The
+ compression program used does not need to implement decompression
+ (*note compressor-requirements::), but it must implement at least the
+ compression level option '-9' and the option '-o FILE' to write the
+ compressed output to FILE. tarlz meets these requirements, and
+ therefore can be used to recompress POSIX tar archives by using a
+ command like 'zupdate --lz='tarlz -9 -z --no-solid' archive.tar.gz'.
+ *Note tarlz manual: (tarlz)Top.
+

File: zutils.info, Node: Problems, Next: Concept index, Prev: Zupdate, Up: Top
@@ -893,24 +981,26 @@ Concept index
* zgrep: Zgrep. (line 6)
* ztest: Ztest. (line 6)
* zupdate: Zupdate. (line 6)
-* zutilsrc: The zutilsrc file. (line 6)
+* zutils.conf: Configuration. (line 6)

Tag Table:
Node: Top217
-Node: Introduction1150
-Node: Common options3897
-Ref: compressor-requirements6134
-Node: The zutilsrc file6529
-Node: Zcat7497
-Node: Zcmp10072
-Node: Zdiff12573
-Node: Zgrep15623
-Node: Ztest21115
-Node: Zupdate23681
-Node: Problems28191
-Node: Concept index28725
+Node: Introduction1156
+Node: Common options4003
+Ref: version4489
+Ref: compressor-requirements6440
+Node: Configuration6835
+Node: Zcat7868
+Node: Zcmp10568
+Node: Zdiff14825
+Node: Zgrep18008
+Node: Ztest24116
+Node: Zupdate26915
+Ref: lz-compressor32442
+Node: Problems33143
+Node: Concept index33677

End Tag Table