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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 14:28:01 +0000
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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 1.12, 7 January 2023).
+
+* Menu:
+
+* Introduction:: Purpose and features of zutils
+* Common options:: Options common to all utilities
+* Configuration:: The configuration file zutils.conf
+* 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) 2009-2023 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. 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 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: The standard POSIX compress format (.Z) is obsolete and is
+only supported through gzip. For this to work, the gzip program used (for
+example GNU gzip) must be able to decompress .Z files.
+
+ 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: Configuration, 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. 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'
+ 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 .Z
+ 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 'zutils.conf'.
+
+'--bz2=COMMAND'
+'--gz=COMMAND'
+'--lz=COMMAND'
+'--xz=COMMAND'
+'--zst=COMMAND'
+ Set program to be used as decompressor for the corresponding format.
+ COMMAND may include arguments. For example '--lz='plzip --threads=2''.
+ '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
+ 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: Configuration, Next: Zcat, Prev: Common options, Up: Top
+
+3 The configuration file 'zutils.conf'
+**************************************
+
+'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.
+'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 'zutils.conf'.
+
+ 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 '$HOME/.config'). The file syntax is fairly
+obvious (and there are further instructions in it):
+
+ 1. Any line beginning with '#' is a comment line.
+
+ 2. Each non-comment line defines the command to be used for the
+ corresponding format, with the syntax:
+ <format> = <compressor> [options]
+ where <format> is one of 'bz2', 'gz', 'lz', 'xz', or 'zst'.
+
+
+File: zutils.info, Node: Zcat, Next: Zcmp, Prev: Configuration, Up: Top
+
+4 Zcat
+******
+
+'zcat' copies each FILE argument to standard output in sequence. If any
+file given is compressed, its decompressed content is copied. If a file
+given does not exist, and its name does not end with one of the known
+extensions, 'zcat' tries the compressed file names corresponding to the
+formats supported. If a file fails to decompress, 'zcat' continues copying
+the rest of the files.
+
+ If a file is specified as '-', data are read from standard input,
+decompressed if needed, and sent to standard output. Data read from
+standard input must be of the same type; all uncompressed or all in the
+same compressed format.
+
+ If no files are specified, recursive searches examine the current working
+directory, and nonrecursive searches read standard input.
+
+ The format for running 'zcat' is:
+
+ zcat [OPTIONS] [FILES]
+
+Exit status is 0 if no errors occurred, 1 otherwise.
+
+ 'zcat' supports the following options:
+
+'-A'
+'--show-all'
+ Equivalent to '-vET'.
+
+'-b'
+'--number-nonblank'
+ Number all nonblank output lines, starting with 1. The line count is
+ unlimited.
+
+'-e'
+ Equivalent to '-vE'.
+
+'-E'
+'--show-ends'
+ Print a '$' 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', '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'
+ 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. Repeating it increases the verbosity
+ level. *Note version::.
+
+
+
+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 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'
+ 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'
+'--list'
+ 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'
+ 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', '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'
+'--quiet'
+'--silent'
+ 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
+
+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', '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'
+ 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. Further -v's increase the verbosity level. *Note
+ version::.
+
+'-w'
+'--ignore-all-space'
+ Ignore all white space.
+
+'-W COLUMNS'
+'--width=COLUMNS'
+ Output at most the specified number of print columns per line in side
+ by side format.
+
+'-y'
+'--side-by-side'
+ Use the side by side output format.
+
+
+
+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.
+
+ 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):
+
+'-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'
+ Interpret PATTERN as an extended regular expression (ERE).
+
+'-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'
+ Interpret PATTERN as a set of newline-separated strings.
+
+'-G'
+'--basic-regexp'
+ Interpret PATTERN as a basic regular expression (BRE). This is the
+ default.
+
+'-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. Stop reading
+ each file on the first match.
+
+'-L'
+'--files-without-match'
+ 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
+ GNU grep 3.5.
+
+'--label=LABEL'
+ Display input actually coming from standard input as input coming from
+ file LABEL.
+
+'--line-buffered'
+ Use line buffering on output. This may cause a performance penalty.
+
+'-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', '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'
+ Interpret PATTERN as a Perl-compatible regular expression (PCRE).
+
+'-q'
+'--quiet'
+'--silent'
+ 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.
+
+'-T'
+'--initial-tab'
+ Make sure that the first character of actual line content lies on a tab
+ stop, so that the alignment of tabs looks normal.
+
+'-U'
+'--binary'
+ Use binary I/O on platforms affected by the bug known as "text mode
+ I/O". (MS-DOS, MS-Windows, OS/2).
+
+'-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. Repeating it increases the
+ verbosity level. *Note version::.
+
+'-w'
+'--word-regexp'
+ Match only whole words.
+
+'-x'
+'--line-regexp'
+ Match only whole lines.
+
+'-Z'
+'--null'
+ Output a zero byte (the ASCII NUL character) instead of the character
+ that normally follows a file name. For example, 'zgrep -lZ' outputs a
+ zero byte after each file name instead of the usual newline. This
+ option makes the output unambiguous, even in the presence of file
+ names containing unusual characters like newlines.
+
+
+
+File: zutils.info, Node: Ztest, Next: Zupdate, Prev: Zgrep, Up: Top
+
+8 Ztest
+*******
+
+'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.
+
+ 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]
+
+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:
+
+'-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.
+
+'-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. *Note version::.
+
+
+
+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.
+
+ 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', '.zst', or '.Z', 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, 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:
+
+ 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 (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'
+ Expand combined file name extensions; recompress '.tbz', '.tbz2',
+ '.tgz', '.txz', and '.tzst' to 'tar.lz'.
+
+'-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.
+
+'-i'
+'--ignore-errors'
+ Ignore non-fatal errors. (See exit status above).
+
+'-k'
+'--keep'
+ Keep (don't delete) the input file after comparing it with the lzip
+ file. Use it when recompressing files from a read-only file system.
+ (See option '--destdir' above).
+
+'-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 and increases the verbosity level. *Note
+ version::.
+
+'-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''.
+
+'--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
+
+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
+*************
+
+
+* 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)
+* zutils.conf: Configuration. (line 6)
+
+
+
+Tag Table:
+Node: Top217
+Node: Introduction1151
+Node: Common options3998
+Ref: version4484
+Ref: compressor-requirements6435
+Node: Configuration6830
+Node: Zcat7863
+Node: Zcmp10563
+Node: Zdiff14820
+Node: Zgrep18003
+Node: Ztest24111
+Node: Zupdate26910
+Ref: lz-compressor32325
+Node: Problems33026
+Node: Concept index33560
+
+End Tag Table
+
+
+Local Variables:
+coding: iso-8859-15
+End: