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|
This is zutils.info, produced by makeinfo version 4.13+ from zutils.texi.
INFO-DIR-SECTION Compression
START-INFO-DIR-ENTRY
* Zutils: (zutils). Utilities dealing with compressed files
END-INFO-DIR-ENTRY
File: zutils.info, Node: Top, Next: Introduction, Up: (dir)
Zutils Manual
*************
This manual is for Zutils (version 1.11, 25 January 2022).
* Menu:
* Introduction:: Purpose and features of zutils
* Common options:: Options common to all utilities
* The zutilsrc file:: The zutils configuration file
* Zcat:: Concatenating compressed files
* Zcmp:: Comparing compressed files byte by byte
* Zdiff:: Comparing compressed files line by line
* Zgrep:: Searching inside compressed files
* Ztest:: Testing the integrity of compressed files
* Zupdate:: Recompressing files to lzip format
* Problems:: Reporting bugs
* Concept index:: Index of concepts
Copyright (C) 2009-2022 Antonio Diaz Diaz.
This manual is free documentation: you have unlimited permission to copy,
distribute, and modify it.
File: zutils.info, Node: Introduction, Next: Common options, Prev: Top, Up: Top
1 Introduction
**************
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.
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 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.
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
values, making them less reliable back ends for zutils. Zstd currently does
not even document its exit status in its man page. *Note
compressor-requirements::.
FORMAT NOTE 1: The option '--format' allows the processing of a subset
of formats in recursive mode and when trying compressed file names. For
example, use the following command to search for the string 'foo' in gzip
and lzip files only: 'zgrep foo -r --format=gz,lz somedir somefile.tar'.
FORMAT NOTE 2: If the option '--force-format' is given, the files are
passed to the corresponding decompressor without verifying their format,
allowing for example the processing of compress'd (.Z) files with gzip:
'zcmp --force-format=gz file.Z file.lz'.
LANGUAGE NOTE: Uncompressed = not compressed = plain data; it may never
have been compressed. Decompressed is used to refer to data which have
undergone the process of decompression.
Numbers given as arguments to options (positions, sizes) 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: Common options, Next: The zutilsrc file, Prev: Introduction, Up: Top
2 Common options
****************
The following options: are available in all the utilities. Rather than
writing identical descriptions for each of the programs, they are described
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.
'-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.
'-M FORMAT_LIST'
'--format=FORMAT_LIST'
Process only the formats listed in the comma-separated FORMAT_LIST.
Valid formats are 'bz2', 'gz', 'lz', 'xz', 'zst', and 'un' for
'uncompressed', meaning "any file name without a known extension".
This option excludes files based on extension, instead of format,
because it is more efficient. The exclusion only applies to names
generated automatically (for example when adding extensions to a file
name or when operating recursively on directories). Files given in the
command line are always processed.
Each format in FORMAT_LIST enables file names with the following
extensions:
bz2 enables .bz2 .tbz .tbz2
gz enables .gz .tgz
lz enables .lz .tlz
xz enables .xz .txz
zst enables .zst .tzst
un enables any other file name
'-N'
'--no-rcfile'
Don't read the runtime configuration file 'zutilsrc'.
'--bz2=COMMAND'
'--gz=COMMAND'
'--lz=COMMAND'
'--xz=COMMAND'
'--zst=COMMAND'
Set program to be used as (de)compressor 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:
1. When called with the option '-d' and without file names, it must
read compressed data from the standard input and produce
decompressed data on the standard output.
2. If the option '-q' is passed to zutils, the compression program
must also accept it.
3. It must return 0 if no errors occurred, and a non-zero value
otherwise.
File: zutils.info, Node: The zutilsrc file, Next: Zcat, Prev: Common options, Up: Top
3 The zutils configuration file 'zutilsrc'
******************************************
'zutilsrc' 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.
The compressors specified in the command line override those specified
in 'zutilsrc'.
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):
1. Any line beginning with '#' is a comment line.
2. Each non-comment line defines the command to be used for the
corresponding format, with the syntax:
<format> = <compressor> [options]
where <format> is one of 'bz2', 'gz', 'lz', 'xz', or 'zst'.
File: zutils.info, Node: Zcat, Next: Zcmp, Prev: The zutilsrc file, 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.
If a file is specified as '-', data are read from standard input,
decompressed if needed, and sent to standard output. Data read from
standard input must 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 zcat is:
zcat [OPTIONS] [FILES]
Exit status is 0 if no errors occurred, 1 otherwise.
zcat supports the following options:
'-A'
'--show-all'
Equivalent to '-vET'.
'-b'
'--number-nonblank'
Number all nonblank output lines, starting with 1. The line count is
unlimited.
'-e'
Equivalent to '-vE'.
'-E'
'--show-ends'
Print a '$' after the end of each line.
'-n'
'--number'
Number all output lines, starting with 1. The line count is unlimited.
'-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.
'-q'
'--quiet'
Quiet operation. Suppress all messages.
'-r'
'--recursive'
For each directory operand, read and process all files in that
directory, recursively. Follow symbolic links given in the command
line, but skip symbolic links that are encountered recursively.
'-R'
'--dereference-recursive'
For each directory operand, read and process all files in that
directory, recursively, following all symbolic links.
'-s'
'--squeeze-blank'
Replace multiple adjacent blank lines with a single blank line.
'-t'
Equivalent to '-vT'.
'-T'
'--show-tabs'
Print TAB characters as '^I'.
'-v'
'--show-nonprinting'
Print control characters except for LF (newline) and TAB using '^'
notation and precede characters larger than 127 with 'M-' (which
stands for "meta").
'--verbose'
Verbose mode. Show error messages.
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.
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
following:
- If FILE1 is compressed, compares its decompressed contents with the
corresponding uncompressed file (the name of FILE1 with the extension
removed).
- If FILE1 is uncompressed, compares it with the decompressed contents
of FILE1.[lz|bz2|gz|zst|xz] (the first one that is found).
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:
'-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").
'-i SIZE'
'--ignore-initial=SIZE'
Ignore any differences in the first SIZE bytes of the input files.
Treat files with fewer than SIZE bytes as if they were empty. If SIZE
is in the form 'SIZE1:SIZE2', ignore the first SIZE1 bytes of the
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.
'-n COUNT'
'--bytes=COUNT'
Compare at most COUNT input bytes.
'-O [FORMAT1][,FORMAT2]'
'--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.
'-q'
'-s'
'--quiet'
'--silent'
Don't print anything; only return an exit status indicating whether the
files differ.
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
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
that messages from diff refer to temporary file names instead of those
specified.
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
following:
- If FILE1 is compressed, compares its decompressed contents with the
corresponding uncompressed file (the name of FILE1 with the extension
removed).
- If FILE1 is uncompressed, compares it with the decompressed contents
of FILE1.[lz|bz2|gz|zst|xz] (the first one that is found).
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):
'-a'
'--text'
Treat all files as text.
'-b'
'--ignore-space-change'
Ignore changes in the amount of white space.
'-B'
'--ignore-blank-lines'
Ignore changes whose lines are all blank.
'-c'
Use the context output format.
'-C N'
'--context=N'
Same as -c but use N lines of context.
'-d'
'--minimal'
Try hard to find a smaller set of changes.
'-E'
'--ignore-tab-expansion'
Ignore changes due to tab expansion.
'-i'
'--ignore-case'
Ignore case differences in file contents.
'-O [FORMAT1][,FORMAT2]'
'--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.
'-p'
'--show-c-function'
Show which C function each change is in.
'-q'
'--brief'
Output only whether files differ.
'-s'
'--report-identical-files'
Report when two files are identical.
'-t'
'--expand-tabs'
Expand tabs to spaces in output.
'-T'
'--initial-tab'
Make tabs line up by prepending a tab.
'-u'
Use the unified output format.
'-U N'
'--unified=N'
Same as -u but use N lines of context.
'-v'
'--verbose'
When specified before '--version', print the version of the diff
program used.
'-w'
'--ignore-all-space'
Ignore all white space.
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
tries the compressed file names corresponding to the formats supported. If
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
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:
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):
'-a'
'--text'
Treat all files as text.
'-A N'
'--after-context=N'
Print N lines of trailing context.
'-b'
'--byte-offset'
Print the byte offset of each line.
'-B N'
'--before-context=N'
Print N lines of leading context.
'-c'
'--count'
Only print a count of matching lines per file.
'-C N'
'--context=N'
Print N lines of output context.
'--color[=WHEN]'
Show matched strings in color. WHEN is 'never', 'always', or 'auto'.
'-e PATTERN'
'--regexp=PATTERN'
Use PATTERN as the pattern to match.
'-E'
'--extended-regexp'
Treat PATTERN as an extended regular expression.
'-f FILE'
'--file=FILE'
Obtain patterns from FILE, one per line.
When searching in several files at once, command substitution can be
used with '-e' to read FILE only once, for example if FILE is not a
regular file: 'zgrep -e "$(cat FILE)" file1.lz file2.gz'
'-F'
'--fixed-strings'
Treat PATTERN as a set of newline-separated strings.
'-h'
'--no-filename'
Suppress the prefixing of file names on output when multiple files are
searched.
'-H'
'--with-filename'
Print the file name for each match.
'-i'
'--ignore-case'
Ignore case distinctions.
'-I'
Ignore binary files.
'-l'
'--files-with-matches'
Only print names of files containing at least one match.
'-L'
'--files-without-match'
Only print names of files not containing any matches.
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
GNU grep 3.5.
'-m N'
'--max-count=N'
Stop after N matches.
'-n'
'--line-number'
Prefix each matched line with its line number in the input file.
'-o'
'--only-matching'
Show only the part of matching lines that actually matches PATTERN.
'-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.
'-q'
'--quiet'
Suppress all messages. Exit immediately with zero status if any match
is found, even if an error was detected.
'-r'
'--recursive'
For each directory operand, read and process all files in that
directory, recursively. Follow symbolic links given in the command
line, but skip symbolic links that are encountered recursively.
'-R'
'--dereference-recursive'
For each directory operand, read and process all files in that
directory, recursively, following all symbolic links.
'-s'
'--no-messages'
Suppress error messages about nonexistent or unreadable files.
'-v'
'--invert-match'
Select non-matching lines.
'--verbose'
Verbose mode. Show error messages. When specified before '--version',
print the version of the grep program used.
'-w'
'--word-regexp'
Match only whole words.
'-x'
'--line-regexp'
Match only whole lines.
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.
If no files are specified, recursive searches examine the current working
directory, and nonrecursive searches read standard input.
Bzip2, gzip, and lzip are the primary formats. Xz and zstd are optional.
If the decompressor for the xz or zstd formats is not found, the
corresponding files are ignored.
Note that error detection in the xz format is broken. First, some xz
files lack integrity information. Second, not all xz decompressors can
verify the integrity of all xz files. Third, section 2.1.1.2 'Stream Flags'
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:
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.
ztest supports the following options:
'-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 any files in a format that the decompressor can't
understand will fail. For example, '--force-format=gz' can test
gzipped (.gz) and compress'd (.Z) files if the compressor used is GNU
gzip.
'-q'
'--quiet'
Quiet operation. Suppress all messages.
'-r'
'--recursive'
For each directory operand, read and process all files in that
directory, recursively. Follow symbolic links given in the command
line, but skip symbolic links that are encountered recursively.
'-R'
'--dereference-recursive'
For each directory operand, read and process all files in that
directory, recursively, following all symbolic links.
'-v'
'--verbose'
Verbose mode. Show the verify status for each file processed.
Further -v's increase the verbosity level.
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
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
rest of the files. The lzip format is chosen as destination because it is
the most appropriate for long-term data archiving.
If no files are specified, recursive searches examine the current working
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
safe and not cause any data loss. Therefore, existing lzip compressed files
are never overwritten nor deleted.
Recompressing files from a read-only file system to another place can be
done by first linking the files from the destination directory and then
compressing the links: 'ln -s /src/foo.gz . && zupdate foo.gz'
Combining the options '--force' and '--keep', as in
'zupdate -f -k *.gz', verifies that there are no differences between each
pair of files in a multiformat set of files.
The names of the original files must have one of the following
extensions:
'.bz2', '.gz', '.xz', or '.zst', which are recompressed to '.lz';
'.tbz', '.tbz2', '.tgz', '.txz', or '.tzst', which are recompressed to
'.tlz'.
Keeping the combined extensions ('.tgz' -> '.tlz') may be useful when
recompressing Slackware packages, for example.
Bzip2, gzip, and lzip are the primary formats. Xz and zstd are optional.
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, 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).
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). Non-zero otherwise.
zupdate supports the following options:
'-f'
'--force'
Don't skip a file for which a lzip compressed version already exists.
'--force' compares the content of the input file with the content of
the existing lzip file and deletes the input file if both contents are
identical.
'-k'
'--keep'
Keep (don't delete) the input file after comparing it with the lzip
file.
'-l'
'--lzip-verbose'
Pass one option '-v' to the lzip compressor so that it shows the
compression ratio for each file processed. Using lzip 1.15 or newer, a
second '-l' shows the progress of compression. Use it together with
'-v' to see the name of the file.
'-q'
'--quiet'
Quiet operation. Suppress all messages.
'-r'
'--recursive'
For each directory operand, read and process all files in that
directory, recursively. Follow symbolic links given in the command
line, but skip symbolic links that are encountered recursively.
'-R'
'--dereference-recursive'
For each directory operand, read and process all files in that
directory, recursively, following all symbolic links.
'-v'
'--verbose'
Verbose mode. Show the files being processed. A second '-v' also shows
the files being ignored.
'-0 .. -9'
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''.
File: zutils.info, Node: Problems, Next: Concept index, Prev: Zupdate, Up: Top
10 Reporting bugs
*****************
There are probably bugs in zutils. There are certainly errors and omissions
in this manual. If you report them, they will get fixed. If you don't, no
one will ever know about them and they will remain unfixed for all
eternity, if not longer.
If you find a bug in zutils, please send electronic mail to
<zutils-bug@nongnu.org>. Include the version number, which you can find by
running 'zupdate --version'.
File: zutils.info, Node: Concept index, Prev: Problems, Up: Top
Concept index
*************
[index ]
* Menu:
* bugs: Problems. (line 6)
* common options: Common options. (line 6)
* getting help: Problems. (line 6)
* introduction: Introduction. (line 6)
* zcat: Zcat. (line 6)
* zcmp: Zcmp. (line 6)
* zdiff: Zdiff. (line 6)
* zgrep: Zgrep. (line 6)
* ztest: Ztest. (line 6)
* zupdate: Zupdate. (line 6)
* zutilsrc: The zutilsrc file. (line 6)
Tag Table:
Node: Top217
Node: Introduction1147
Node: Common options3947
Ref: compressor-requirements6181
Node: The zutilsrc file6576
Node: Zcat7544
Node: Zcmp10119
Node: Zdiff12620
Node: Zgrep15478
Node: Ztest19819
Node: Zupdate22513
Node: Problems26607
Node: Concept index27141
End Tag Table
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