Adding upstream version 1.10.upstream/1.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

8 files changed, 2360 insertions, 0 deletions

diff --git a/doc/zcat.1 b/doc/zcat.1
new file mode 100644
index 0000000..fbaf821
--- /dev/null
+++ b/doc/zcat.1
@@ -0,0 +1,103 @@
+.\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.16.
+.TH ZCAT "1" "January 2021" "zutils 1.10" "User Commands"
+.SH NAME
+zcat \- decompress and concatenate files to standard output
+.SH SYNOPSIS
+.B zcat
+[\fI\,options\/\fR] [\fI\,files\/\fR]
+.SH DESCRIPTION
+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.
+.PP
+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.
+.PP
+If no files are specified, recursive searches examine the current
+working directory, and nonrecursive searches read standard input.
+.PP
+The formats supported are bzip2, gzip, lzip, and xz.
+.PP
+Exit status is 0 if no errors occurred, 1 otherwise.
+.SH OPTIONS
+.TP
+\fB\-h\fR, \fB\-\-help\fR
+display this help and exit
+.TP
+\fB\-V\fR, \fB\-\-version\fR
+output version information and exit
+.TP
+\fB\-A\fR, \fB\-\-show\-all\fR
+equivalent to '\-vET'
+.TP
+\fB\-b\fR, \fB\-\-number\-nonblank\fR
+number nonblank output lines
+.TP
+\fB\-e\fR
+equivalent to '\-vE'
+.TP
+\fB\-E\fR, \fB\-\-show\-ends\fR
+display '$' at end of each line
+.TP
+\fB\-M\fR, \fB\-\-format=\fR<list>
+process only the formats in <list>
+.TP
+\fB\-n\fR, \fB\-\-number\fR
+number all output lines
+.TP
+\fB\-N\fR, \fB\-\-no\-rcfile\fR
+don't read runtime configuration file
+.TP
+\fB\-O\fR, \fB\-\-force\-format=\fR<fmt>
+force the format given (bz2, gz, lz, xz)
+.TP
+\fB\-q\fR, \fB\-\-quiet\fR
+suppress all messages
+.TP
+\fB\-r\fR, \fB\-\-recursive\fR
+operate recursively on directories
+.TP
+\fB\-R\fR, \fB\-\-dereference\-recursive\fR
+recursively follow symbolic links
+.TP
+\fB\-s\fR, \fB\-\-squeeze\-blank\fR
+never more than one single blank line
+.TP
+\fB\-t\fR
+equivalent to '\-vT'
+.TP
+\fB\-T\fR, \fB\-\-show\-tabs\fR
+display TAB characters as '^I'
+.TP
+\fB\-v\fR, \fB\-\-show\-nonprinting\fR
+use '^' and 'M\-' notation, except for LF and TAB
+.TP
+\fB\-\-verbose\fR
+verbose mode (show error messages)
+.TP
+\fB\-\-bz2=\fR<command>
+set compressor and options for bzip2 format
+.TP
+\fB\-\-gz=\fR<command>
+set compressor and options for gzip format
+.TP
+\fB\-\-lz=\fR<command>
+set compressor and options for lzip format
+.TP
+\fB\-\-xz=\fR<command>
+set compressor and options for xz format
+.SH "REPORTING BUGS"
+Report bugs to zutils\-bug@nongnu.org
+.br
+Zutils home page: http://www.nongnu.org/zutils/zutils.html
+.SH COPYRIGHT
+Copyright \(co 2021 Antonio Diaz Diaz.
+License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>
+.br
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
diff --git a/doc/zcmp.1 b/doc/zcmp.1
new file mode 100644
index 0000000..5ae5231
--- /dev/null
+++ b/doc/zcmp.1
@@ -0,0 +1,90 @@
+.\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.16.
+.TH ZCMP "1" "January 2021" "zutils 1.10" "User Commands"
+.SH NAME
+zcmp \- decompress and compare two files byte by byte
+.SH SYNOPSIS
+.B zcmp
+[\fI\,options\/\fR] \fI\,file1 \/\fR[\fI\,file2\/\fR]
+.SH DESCRIPTION
+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.
+.PP
+The formats supported are bzip2, gzip, lzip, and xz.
+.PP
+zcmp 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:
+.IP
+\- If file1 is compressed, compares its decompressed contents with
+the corresponding uncompressed file (the name of file1 with the
+extension removed).
+.IP
+\- If file1 is uncompressed, compares it with the decompressed
+contents of file1.[lz|bz2|gz|xz] (the first one that is found).
+.PP
+Exit status is 0 if inputs are identical, 1 if different, 2 if trouble.
+.SH OPTIONS
+.TP
+\fB\-h\fR, \fB\-\-help\fR
+display this help and exit
+.TP
+\fB\-V\fR, \fB\-\-version\fR
+output version information and exit
+.TP
+\fB\-b\fR, \fB\-\-print\-bytes\fR
+print differing bytes
+.TP
+\fB\-i\fR, \fB\-\-ignore\-initial=\fR<n>[:<n2>]
+ignore differences in the first <n> bytes
+.TP
+\fB\-l\fR, \fB\-\-list\fR
+list position, value of all differing bytes
+.TP
+\fB\-M\fR, \fB\-\-format=\fR<list>
+process only the formats in <list>
+.TP
+\fB\-n\fR, \fB\-\-bytes=\fR<n>
+compare at most <n> bytes
+.TP
+\fB\-N\fR, \fB\-\-no\-rcfile\fR
+don't read runtime configuration file
+.TP
+\fB\-O\fR, \fB\-\-force\-format\fR=\fI\,[\/\fR<f1>][,<f2>]
+force the formats given (bz2, gz, lz, xz)
+.TP
+\fB\-q\fR, \fB\-\-quiet\fR
+suppress all messages
+.TP
+\fB\-s\fR, \fB\-\-silent\fR
+(same as \fB\-\-quiet\fR)
+.TP
+\fB\-v\fR, \fB\-\-verbose\fR
+verbose mode (same as \fB\-\-list\fR)
+.TP
+\fB\-\-bz2=\fR<command>
+set compressor and options for bzip2 format
+.TP
+\fB\-\-gz=\fR<command>
+set compressor and options for gzip format
+.TP
+\fB\-\-lz=\fR<command>
+set compressor and options for lzip format
+.TP
+\fB\-\-xz=\fR<command>
+set compressor and options for xz format
+.PP
+Numbers may be followed by a multiplier: k = kB = 10^3 = 1000,
+Ki = KiB = 2^10 = 1024, M = 10^6, Mi = 2^20, G = 10^9, Gi = 2^30, etc...
+.SH "REPORTING BUGS"
+Report bugs to zutils\-bug@nongnu.org
+.br
+Zutils home page: http://www.nongnu.org/zutils/zutils.html
+.SH COPYRIGHT
+Copyright \(co 2021 Antonio Diaz Diaz.
+License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>
+.br
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
diff --git a/doc/zdiff.1 b/doc/zdiff.1
new file mode 100644
index 0000000..65a34b7
--- /dev/null
+++ b/doc/zdiff.1
@@ -0,0 +1,121 @@
+.\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.16.
+.TH ZDIFF "1" "January 2021" "zutils 1.10" "User Commands"
+.SH NAME
+zdiff \- decompress and compare two files line by line
+.SH SYNOPSIS
+.B zdiff
+[\fI\,options\/\fR] \fI\,file1 \/\fR[\fI\,file2\/\fR]
+.SH DESCRIPTION
+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.
+.PP
+The formats supported are bzip2, gzip, lzip, and xz.
+.PP
+zdiff 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:
+.IP
+\- If file1 is compressed, compares its decompressed contents with
+the corresponding uncompressed file (the name of file1 with the
+extension removed).
+.IP
+\- If file1 is uncompressed, compares it with the decompressed
+contents of file1.[lz|bz2|gz|xz] (the first one that is found).
+.PP
+Exit status is 0 if inputs are identical, 1 if different, 2 if trouble.
+Some options only work if the diff program used supports them.
+.SH OPTIONS
+.TP
+\fB\-h\fR, \fB\-\-help\fR
+display this help and exit
+.TP
+\fB\-V\fR, \fB\-\-version\fR
+output version information and exit
+.TP
+\fB\-a\fR, \fB\-\-text\fR
+treat all files as text
+.TP
+\fB\-b\fR, \fB\-\-ignore\-space\-change\fR
+ignore changes in the amount of white space
+.TP
+\fB\-B\fR, \fB\-\-ignore\-blank\-lines\fR
+ignore changes whose lines are all blank
+.TP
+\fB\-c\fR
+use the context output format
+.TP
+\fB\-C\fR, \fB\-\-context=\fR<n>
+same as \fB\-c\fR but use <n> lines of context
+.TP
+\fB\-d\fR, \fB\-\-minimal\fR
+try hard to find a smaller set of changes
+.TP
+\fB\-E\fR, \fB\-\-ignore\-tab\-expansion\fR
+ignore changes due to tab expansion
+.TP
+\fB\-i\fR, \fB\-\-ignore\-case\fR
+ignore case differences in file contents
+.TP
+\fB\-M\fR, \fB\-\-format=\fR<list>
+process only the formats in <list>
+.TP
+\fB\-N\fR, \fB\-\-no\-rcfile\fR
+don't read runtime configuration file
+.TP
+\fB\-O\fR, \fB\-\-force\-format\fR=\fI\,[\/\fR<f1>][,<f2>]
+force the formats given (bz2, gz, lz, xz)
+.TP
+\fB\-p\fR, \fB\-\-show\-c\-function\fR
+show which C function each change is in
+.TP
+\fB\-q\fR, \fB\-\-brief\fR
+output only whether files differ
+.TP
+\fB\-s\fR, \fB\-\-report\-identical\-files\fR
+report when two files are identical
+.TP
+\fB\-t\fR, \fB\-\-expand\-tabs\fR
+expand tabs to spaces in output
+.TP
+\fB\-T\fR, \fB\-\-initial\-tab\fR
+make tabs line up by prepending a tab
+.TP
+\fB\-u\fR
+use the unified output format
+.TP
+\fB\-U\fR, \fB\-\-unified=\fR<n>
+same as \fB\-u\fR but use <n> lines of context
+.TP
+\fB\-w\fR, \fB\-\-ignore\-all\-space\fR
+ignore all white space
+.TP
+\fB\-W\fR, \fB\-\-width=\fR<n>
+output at most <n> print columns
+.TP
+\fB\-y\fR, \fB\-\-side\-by\-side\fR
+output in two columns
+.TP
+\fB\-\-bz2=\fR<command>
+set compressor and options for bzip2 format
+.TP
+\fB\-\-gz=\fR<command>
+set compressor and options for gzip format
+.TP
+\fB\-\-lz=\fR<command>
+set compressor and options for lzip format
+.TP
+\fB\-\-xz=\fR<command>
+set compressor and options for xz format
+.SH "REPORTING BUGS"
+Report bugs to zutils\-bug@nongnu.org
+.br
+Zutils home page: http://www.nongnu.org/zutils/zutils.html
+.SH COPYRIGHT
+Copyright \(co 2021 Antonio Diaz Diaz.
+License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>
+.br
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
diff --git a/doc/zgrep.1 b/doc/zgrep.1
new file mode 100644
index 0000000..69ed0cd
--- /dev/null
+++ b/doc/zgrep.1
@@ -0,0 +1,153 @@
+.\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.16.
+.TH ZGREP "1" "January 2021" "zutils 1.10" "User Commands"
+.SH NAME
+zgrep \- search compressed files for a regular expression
+.SH SYNOPSIS
+.B zgrep
+[\fI\,options\/\fR] \fI\,<pattern> \/\fR[\fI\,files\/\fR]
+.SH DESCRIPTION
+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.
+.PP
+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.
+.PP
+If no files are specified, recursive searches examine the current
+working directory, and nonrecursive searches read standard input.
+.PP
+The formats supported are bzip2, gzip, lzip, and xz.
+.PP
+Exit status is 0 if match, 1 if no match, 2 if trouble.
+Some options only work if the grep program used supports them.
+.SH OPTIONS
+.TP
+\fB\-\-help\fR
+display this help and exit
+.TP
+\fB\-V\fR, \fB\-\-version\fR
+output version information and exit
+.TP
+\fB\-a\fR, \fB\-\-text\fR
+treat all files as text
+.TP
+\fB\-A\fR, \fB\-\-after\-context=\fR<n>
+print <n> lines of trailing context
+.TP
+\fB\-b\fR, \fB\-\-byte\-offset\fR
+print the byte offset of each line
+.TP
+\fB\-B\fR, \fB\-\-before\-context=\fR<n>
+print <n> lines of leading context
+.TP
+\fB\-c\fR, \fB\-\-count\fR
+only print a count of matching lines per file
+.TP
+\fB\-C\fR, \fB\-\-context=\fR<n>
+print <n> lines of output context
+.TP
+\fB\-\-color[=\fR<when>]
+show matched strings in color
+.TP
+\fB\-e\fR, \fB\-\-regexp=\fR<pattern>
+use <pattern> as the pattern to match
+.TP
+\fB\-E\fR, \fB\-\-extended\-regexp\fR
+<pattern> is an extended regular expression
+.TP
+\fB\-f\fR, \fB\-\-file=\fR<file>
+obtain patterns from <file>
+.TP
+\fB\-F\fR, \fB\-\-fixed\-strings\fR
+<pattern> is a set of newline\-separated strings
+.TP
+\fB\-h\fR, \fB\-\-no\-filename\fR
+suppress the prefixing filename on output
+.TP
+\fB\-H\fR, \fB\-\-with\-filename\fR
+print the filename for each match
+.TP
+\fB\-i\fR, \fB\-\-ignore\-case\fR
+ignore case distinctions
+.TP
+\fB\-I\fR
+ignore binary files
+.TP
+\fB\-l\fR, \fB\-\-files\-with\-matches\fR
+only print names of files containing matches
+.TP
+\fB\-L\fR, \fB\-\-files\-without\-match\fR
+only print names of files containing no matches
+.TP
+\fB\-m\fR, \fB\-\-max\-count=\fR<n>
+stop after <n> matches
+.TP
+\fB\-M\fR, \fB\-\-format=\fR<list>
+process only the formats in <list>
+.TP
+\fB\-n\fR, \fB\-\-line\-number\fR
+print the line number of each line
+.TP
+\fB\-N\fR, \fB\-\-no\-rcfile\fR
+don't read runtime configuration file
+.TP
+\fB\-o\fR, \fB\-\-only\-matching\fR
+show only the part of a line matching <pattern>
+.TP
+\fB\-O\fR, \fB\-\-force\-format=\fR<fmt>
+force the format given (bz2, gz, lz, xz)
+.TP
+\fB\-q\fR, \fB\-\-quiet\fR
+suppress all messages
+.TP
+\fB\-r\fR, \fB\-\-recursive\fR
+operate recursively on directories
+.TP
+\fB\-R\fR, \fB\-\-dereference\-recursive\fR
+recursively follow symbolic links
+.TP
+\fB\-s\fR, \fB\-\-no\-messages\fR
+suppress error messages
+.TP
+\fB\-v\fR, \fB\-\-invert\-match\fR
+select non\-matching lines
+.TP
+\fB\-\-verbose\fR
+verbose mode (show error messages)
+.TP
+\fB\-w\fR, \fB\-\-word\-regexp\fR
+match only whole words
+.TP
+\fB\-x\fR, \fB\-\-line\-regexp\fR
+match only whole lines
+.TP
+\fB\-\-bz2=\fR<command>
+set compressor and options for bzip2 format
+.TP
+\fB\-\-gz=\fR<command>
+set compressor and options for gzip format
+.TP
+\fB\-\-lz=\fR<command>
+set compressor and options for lzip format
+.TP
+\fB\-\-xz=\fR<command>
+set compressor and options for xz format
+.PP
+Numbers may be followed by a multiplier: k = kB = 10^3 = 1000,
+Ki = KiB = 2^10 = 1024, M = 10^6, Mi = 2^20, G = 10^9, Gi = 2^30, etc...
+.SH "REPORTING BUGS"
+Report bugs to zutils\-bug@nongnu.org
+.br
+Zutils home page: http://www.nongnu.org/zutils/zutils.html
+.SH COPYRIGHT
+Copyright \(co 2021 Antonio Diaz Diaz.
+License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>
+.br
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
diff --git a/doc/ztest.1 b/doc/ztest.1
new file mode 100644
index 0000000..45cda27
--- /dev/null
+++ b/doc/ztest.1
@@ -0,0 +1,82 @@
+.\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.16.
+.TH ZTEST "1" "January 2021" "zutils 1.10" "User Commands"
+.SH NAME
+ztest \- verify the integrity of compressed files
+.SH SYNOPSIS
+.B ztest
+[\fI\,options\/\fR] [\fI\,files\/\fR]
+.SH DESCRIPTION
+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.
+.PP
+If no files are specified, recursive searches examine the current
+working directory, and nonrecursive searches read standard input.
+.PP
+The formats supported are bzip2, gzip, lzip, and xz.
+.PP
+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.
+.PP
+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.
+.SH OPTIONS
+.TP
+\fB\-h\fR, \fB\-\-help\fR
+display this help and exit
+.TP
+\fB\-V\fR, \fB\-\-version\fR
+output version information and exit
+.TP
+\fB\-M\fR, \fB\-\-format=\fR<list>
+process only the formats in <list>
+.TP
+\fB\-N\fR, \fB\-\-no\-rcfile\fR
+don't read runtime configuration file
+.TP
+\fB\-O\fR, \fB\-\-force\-format=\fR<fmt>
+force the format given (bz2, gz, lz, xz)
+.TP
+\fB\-q\fR, \fB\-\-quiet\fR
+suppress all messages
+.TP
+\fB\-r\fR, \fB\-\-recursive\fR
+operate recursively on directories
+.TP
+\fB\-R\fR, \fB\-\-dereference\-recursive\fR
+recursively follow symbolic links
+.TP
+\fB\-v\fR, \fB\-\-verbose\fR
+be verbose (a 2nd \fB\-v\fR gives more)
+.TP
+\fB\-\-bz2=\fR<command>
+set compressor and options for bzip2 format
+.TP
+\fB\-\-gz=\fR<command>
+set compressor and options for gzip format
+.TP
+\fB\-\-lz=\fR<command>
+set compressor and options for lzip format
+.TP
+\fB\-\-xz=\fR<command>
+set compressor and options for xz format
+.SH "REPORTING BUGS"
+Report bugs to zutils\-bug@nongnu.org
+.br
+Zutils home page: http://www.nongnu.org/zutils/zutils.html
+.SH COPYRIGHT
+Copyright \(co 2021 Antonio Diaz Diaz.
+License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>
+.br
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
diff --git a/doc/zupdate.1 b/doc/zupdate.1
new file mode 100644
index 0000000..dcd3d24
--- /dev/null
+++ b/doc/zupdate.1
@@ -0,0 +1,91 @@
+.\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.16.
+.TH ZUPDATE "1" "January 2021" "zutils 1.10" "User Commands"
+.SH NAME
+zupdate \- recompress bzip2, gzip, xz files to lzip format
+.SH SYNOPSIS
+.B zupdate
+[\fI\,options\/\fR] [\fI\,files\/\fR]
+.SH DESCRIPTION
+zupdate recompresses files from bzip2, gzip, and xz 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. The lzip format
+is chosen as destination because it is the most appropriate for
+long\-term data archiving.
+.PP
+If no files are specified, recursive searches examine the current
+working directory, and nonrecursive searches do nothing.
+.PP
+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.
+.PP
+The names of the original files must have one of the following extensions:
+\&'.bz2', '.gz', or '.xz', which are recompressed to '.lz';
+\&'.tbz', '.tbz2', '.tgz', or '.txz', which are recompressed to '.tlz'.
+.PP
+Exit status is 0 if all the compressed files were successfully recompressed
+(if needed), compared, and deleted (if requested). Non\-zero otherwise.
+.SH OPTIONS
+.TP
+\fB\-h\fR, \fB\-\-help\fR
+display this help and exit
+.TP
+\fB\-V\fR, \fB\-\-version\fR
+output version information and exit
+.TP
+\fB\-f\fR, \fB\-\-force\fR
+don't skip a file even if the .lz exists
+.TP
+\fB\-k\fR, \fB\-\-keep\fR
+keep (don't delete) input files
+.TP
+\fB\-l\fR, \fB\-\-lzip\-verbose\fR
+pass one option \fB\-v\fR to the lzip compressor
+.TP
+\fB\-M\fR, \fB\-\-format=\fR<list>
+process only the formats in <list>
+.TP
+\fB\-N\fR, \fB\-\-no\-rcfile\fR
+don't read runtime configuration file
+.TP
+\fB\-q\fR, \fB\-\-quiet\fR
+suppress all messages
+.TP
+\fB\-r\fR, \fB\-\-recursive\fR
+operate recursively on directories
+.TP
+\fB\-R\fR, \fB\-\-dereference\-recursive\fR
+recursively follow symbolic links
+.TP
+\fB\-v\fR, \fB\-\-verbose\fR
+be verbose (a 2nd \fB\-v\fR gives more)
+.TP
+\fB\-0\fR .. \fB\-9\fR
+set compression level [default 9]
+.TP
+\fB\-\-bz2=\fR<command>
+set compressor and options for bzip2 format
+.TP
+\fB\-\-gz=\fR<command>
+set compressor and options for gzip format
+.TP
+\fB\-\-lz=\fR<command>
+set compressor and options for lzip format
+.TP
+\fB\-\-xz=\fR<command>
+set compressor and options for xz format
+.SH "REPORTING BUGS"
+Report bugs to zutils\-bug@nongnu.org
+.br
+Zutils home page: http://www.nongnu.org/zutils/zutils.html
+.SH COPYRIGHT
+Copyright \(co 2021 Antonio Diaz Diaz.
+License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>
+.br
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
diff --git a/doc/zutils.info b/doc/zutils.info
new file mode 100644
index 0000000..854100f
--- /dev/null
+++ b/doc/zutils.info
@@ -0,0 +1,838 @@
+This is zutils.info, produced by makeinfo version 4.13+ from zutils.texi.
+
+INFO-DIR-SECTION Data 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 1.10, 5 January 2021).
+
+* 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) 2009-2021 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, and xz.
+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. *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:
+'zgrep foo -r --format=bz2,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.
+
+'-M FORMAT_LIST'
+'--format=FORMAT_LIST'
+     Process only the formats listed in the comma-separated FORMAT_LIST.
+     Valid formats are 'bz2', 'gz', 'lz', 'xz', 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
+     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'
+     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 other three 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', 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', or 'xz'.
+
+
+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', and 'xz'. 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|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', and 'xz'. 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|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', and 'xz'. 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.
+
+'-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', and 'xz'. 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.
+
+'-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.
+
+   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', and 'xz'. 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, and xz 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', or '.xz', which are recompressed to '.lz';
+'.tbz', '.tbz2', '.tgz', or '.txz', which are recompressed to '.tlz'.
+Keeping the combined extensions ('.tgz' -> '.tlz') may be useful when
+recompressing Slackware packages, for example.
+
+   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
+*************
+
+
+* 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: Top222
+Node: Introduction1151
+Node: Common options3776
+Ref: compressor-requirements5847
+Node: The zutilsrc file6219
+Node: Zcat7180
+Node: Zcmp9743
+Node: Zdiff12233
+Node: Zgrep14973
+Node: Ztest19218
+Node: Zupdate21725
+Node: Problems25409
+Node: Concept index25943
+
+End Tag Table
+
+
+Local Variables:
+coding: iso-8859-15
+End:
diff --git a/doc/zutils.texi b/doc/zutils.texi
new file mode 100644
index 0000000..c494185
--- /dev/null
+++ b/doc/zutils.texi
@@ -0,0 +1,882 @@
+\input texinfo @c -*-texinfo-*-
+@c %**start of header
+@setfilename zutils.info
+@documentencoding ISO-8859-15
+@settitle Zutils Manual
+@finalout
+@c %**end of header
+
+@set UPDATED 5 January 2021
+@set VERSION 1.10
+
+@dircategory Data Compression
+@direntry
+* Zutils: (zutils).             Utilities dealing with compressed files
+@end direntry
+
+
+@ifnothtml
+@titlepage
+@title Zutils
+@subtitle Utilities dealing with compressed files
+@subtitle for Zutils version @value{VERSION}, @value{UPDATED}
+@author by Antonio Diaz Diaz
+
+@page
+@vskip 0pt plus 1filll
+@end titlepage
+
+@contents
+@end ifnothtml
+
+@ifnottex
+@node Top
+@top
+
+This manual is for Zutils (version @value{VERSION}, @value{UPDATED}).
+
+@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
+@end menu
+
+@sp 1
+Copyright @copyright{} 2009-2021 Antonio Diaz Diaz.
+
+This manual is free documentation: you have unlimited permission to copy,
+distribute, and modify it.
+@end ifnottex
+
+
+@node Introduction
+@chapter Introduction
+@cindex introduction
+
+@uref{http://www.nongnu.org/zutils/zutils.html,,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 @samp{--recursive} is very efficient in
+those utilities supporting it.
+
+@noindent
+The utilities provided are zcat, zcmp, zdiff, zgrep, ztest, and zupdate.@*
+The formats supported are bzip2, gzip, lzip, and xz.@*
+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.
+@xref{compressor-requirements}.
+
+FORMAT NOTE 1: The option @samp{--format} allows the processing of a subset
+of formats in recursive mode and when trying compressed file names:
+@w{@samp{zgrep foo -r --format=bz2,lz somedir somefile.tar}}.
+
+FORMAT NOTE 2: If the option @samp{--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:
+@w{@samp{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.
+
+@sp 1
+Numbers given as arguments to options (positions, sizes) may be followed
+by a multiplier and an optional @samp{B} for "byte".
+
+Table of SI and binary prefixes (unit multipliers):
+
+@multitable {Prefix} {kilobyte  (10^3 = 1000)} {|} {Prefix} {kibibyte (2^10 = 1024)}
+@item Prefix @tab Value               @tab | @tab Prefix @tab Value
+@item k @tab kilobyte  (10^3 = 1000)  @tab | @tab Ki @tab kibibyte (2^10 = 1024)
+@item M @tab megabyte  (10^6)         @tab | @tab Mi @tab mebibyte (2^20)
+@item G @tab gigabyte  (10^9)         @tab | @tab Gi @tab gibibyte (2^30)
+@item T @tab terabyte  (10^12)        @tab | @tab Ti @tab tebibyte (2^40)
+@item P @tab petabyte  (10^15)        @tab | @tab Pi @tab pebibyte (2^50)
+@item E @tab exabyte   (10^18)        @tab | @tab Ei @tab exbibyte (2^60)
+@item Z @tab zettabyte (10^21)        @tab | @tab Zi @tab zebibyte (2^70)
+@item Y @tab yottabyte (10^24)        @tab | @tab Yi @tab yobibyte (2^80)
+@end multitable
+
+
+@node Common options
+@chapter Common options
+@cindex common options
+
+The following
+@uref{http://www.nongnu.org/arg-parser/manual/arg_parser_manual.html#Argument-syntax,,options}:
+are available in all the utilities. Rather than writing identical
+descriptions for each of the programs, they are described here.
+@ifnothtml
+@xref{Argument syntax,,,arg_parser}.
+@end ifnothtml
+
+@table @code
+@item -h
+@itemx --help
+Print an informative help message describing the options and exit. zgrep
+only supports the @samp{--help} form of this option.
+
+@item -V
+@itemx --version
+Print the version number on the standard output and exit.
+This version number should be included in all bug reports.
+
+@item -M @var{format_list}
+@itemx --format=@var{format_list}
+Process only the formats listed in the comma-separated
+@var{format_list}. Valid formats are @samp{bz2}, @samp{gz}, @samp{lz},
+@samp{xz}, and @samp{un} for @samp{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 @var{format_list} enables file names with the following
+extensions:
+
+@multitable {bz2} {enables} {any other file name}
+@item bz2 @tab enables @tab .bz2 .tbz .tbz2
+@item gz  @tab enables @tab .gz .tgz
+@item lz  @tab enables @tab .lz .tlz
+@item xz  @tab enables @tab .xz .txz
+@item un  @tab enables @tab any other file name
+@end multitable
+
+@item -N
+@itemx --no-rcfile
+Don't read the runtime configuration file @samp{zutilsrc}.
+
+@item --bz2=@var{command}
+@itemx --gz=@var{command}
+@itemx --lz=@var{command}
+@itemx --xz=@var{command}
+Set program to be used as (de)compressor for the corresponding format.
+@var{command} may include arguments. For example
+@w{@samp{--lz='plzip --threads=2'}}. The program set with @samp{--lz} is
+used for both compression and decompression. The other three are used only
+for decompression. The name of the program can't begin with @samp{-}. These
+options override the values set in @file{zutilsrc}. The compression program
+used must meet three requirements:
+
+@anchor{compressor-requirements}
+@enumerate
+@item
+When called with the option @samp{-d}, it must read compressed data from
+the standard input and produce decompressed data on the standard output.
+@item
+If the option @samp{-q} is passed to zutils, the compression program must
+also accept it.
+@item
+It must return 0 if no errors occurred, and a non-zero value otherwise.
+@end enumerate
+
+@end table
+
+
+@node The zutilsrc file
+@chapter The zutils configuration file 'zutilsrc'
+@cindex zutilsrc
+
+@file{zutilsrc} is the runtime configuration file for zutils. In it you
+may define the compressor name and options to be used for each format.
+@file{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 @file{zutilsrc}.
+
+You may copy the system @file{zutilsrc} file @file{$@{sysconfdir@}/zutilsrc}
+to @file{$HOME/.zutilsrc} and customize these options as you like. The file
+syntax is fairly obvious (and there are further instructions in it):
+
+@enumerate
+@item
+Any line beginning with @samp{#} is a comment line.
+@item
+Each non-comment line defines the command to be used for the corresponding
+format, with the syntax:
+@example
+<format> = <compressor> [options]
+@end example
+where <format> is one of @samp{bz2}, @samp{gz}, @samp{lz}, or @samp{xz}.
+@end enumerate
+
+
+@node Zcat
+@chapter Zcat
+@cindex zcat
+
+zcat copies each @var{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 @samp{-}, 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:
+
+@example
+zcat [@var{options}] [@var{files}]
+@end example
+
+@noindent
+Exit status is 0 if no errors occurred, 1 otherwise.
+
+zcat supports the following options:
+
+@table @code
+@item -A
+@itemx --show-all
+Equivalent to @samp{-vET}.
+
+@item -b
+@itemx --number-nonblank
+Number all nonblank output lines, starting with 1. The line count is
+unlimited.
+
+@item -e
+Equivalent to @samp{-vE}.
+
+@item -E
+@itemx --show-ends
+Print a @samp{$} after the end of each line.
+
+@item -n
+@itemx --number
+Number all output lines, starting with 1. The line count is unlimited.
+
+@item -O @var{format}
+@itemx --force-format=@var{format}
+Force the compressed format given. Valid values for @var{format} are
+@samp{bz2}, @samp{gz}, @samp{lz}, and @samp{xz}. 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.
+
+@item -q
+@itemx --quiet
+Quiet operation. Suppress all messages.
+
+@item -r
+@itemx --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.
+
+@item -R
+@itemx --dereference-recursive
+For each directory operand, read and process all files in that directory,
+recursively, following all symbolic links.
+
+@item -s
+@itemx --squeeze-blank
+Replace multiple adjacent blank lines with a single blank line.
+
+@item -t
+Equivalent to @samp{-vT}.
+
+@item -T
+@itemx --show-tabs
+Print TAB characters as @samp{^I}.
+
+@item -v
+@itemx --show-nonprinting
+Print control characters except for LF (newline) and TAB using @samp{^}
+notation and precede characters larger than 127 with @samp{M-} (which
+stands for "meta").
+
+@item --verbose
+Verbose mode. Show error messages.
+
+@end table
+
+
+@node Zcmp
+@chapter Zcmp
+@cindex 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 @samp{-} used as a @var{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:
+
+@example
+zcmp [@var{options}] @var{file1} [@var{file2}]
+@end example
+
+@noindent
+This compares @var{file1} to @var{file2}. The standard input is used only if
+@var{file1} or @var{file2} refers to standard input. If @var{file2} is
+omitted zcmp tries the following:
+
+@itemize -
+@item
+If @var{file1} is compressed, compares its decompressed contents with
+the corresponding uncompressed file (the name of @var{file1} with the
+extension removed).
+@item
+If @var{file1} is uncompressed, compares it with the decompressed
+contents of @var{file1}.[lz|bz2|gz|xz] (the first one that is found).
+@end itemize
+
+@noindent
+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:
+
+@table @code
+@item -b
+@itemx --print-bytes
+Print the differing bytes. Print control bytes as a @samp{^} followed by
+a letter, and precede bytes larger than 127 with @samp{M-} (which stands
+for "meta").
+
+@item -i @var{size}
+@itemx --ignore-initial=@var{size}
+Ignore any differences in the first @var{size} bytes of the input files.
+Treat files with fewer than @var{size} bytes as if they were empty. If
+@var{size} is in the form @samp{@var{size1}:@var{size2}}, ignore the
+first @var{size1} bytes of the first input file and the first
+@var{size2} bytes of the second input file.
+
+@item -l
+@itemx -v
+@itemx --list
+@itemx --verbose
+Print the byte numbers (in decimal) and values (in octal) of all
+differing bytes.
+
+@item -n @var{count}
+@itemx --bytes=@var{count}
+Compare at most @var{count} input bytes.
+
+@item -O [@var{format1}][,@var{format2}]
+@itemx --force-format=[@var{format1}][,@var{format2}]
+Force the compressed formats given. Any of @var{format1} or
+@var{format2} may be omitted and the corresponding format will be
+automatically detected. Valid values for @var{format} are @samp{bz2},
+@samp{gz}, @samp{lz}, and @samp{xz}. 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
+@var{file1} and @var{file2} must be given. Other names won't be tried.
+
+@item -q
+@itemx -s
+@itemx --quiet
+@itemx --silent
+Don't print anything; only return an exit status indicating whether the
+files differ.
+
+@end table
+
+
+@node Zdiff
+@chapter Zdiff
+@cindex zdiff
+
+zdiff compares two files and, if they differ, writes to standard output the
+differences line by line. A hyphen @samp{-} used as a @var{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:
+
+@example
+zdiff [@var{options}] @var{file1} [@var{file2}]
+@end example
+
+@noindent
+This compares @var{file1} to @var{file2}. The standard input is used only if
+@var{file1} or @var{file2} refers to standard input. If @var{file2} is
+omitted zdiff tries the following:
+
+@itemize -
+@item
+If @var{file1} is compressed, compares its decompressed contents with
+the corresponding uncompressed file (the name of @var{file1} with the
+extension removed).
+@item
+If @var{file1} is uncompressed, compares it with the decompressed
+contents of @var{file1}.[lz|bz2|gz|xz] (the first one that is found).
+@end itemize
+
+@noindent
+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):
+
+@table @code
+@item -a
+@itemx --text
+Treat all files as text.
+
+@item -b
+@itemx --ignore-space-change
+Ignore changes in the amount of white space.
+
+@item -B
+@itemx --ignore-blank-lines
+Ignore changes whose lines are all blank.
+
+@itemx -c
+Use the context output format.
+
+@item -C @var{n}
+@itemx --context=@var{n}
+Same as -c but use @var{n} lines of context.
+
+@item -d
+@itemx --minimal
+Try hard to find a smaller set of changes.
+
+@item -E
+@itemx --ignore-tab-expansion
+Ignore changes due to tab expansion.
+
+@item -i
+@itemx --ignore-case
+Ignore case differences in file contents.
+
+@item -O [@var{format1}][,@var{format2}]
+@itemx --force-format=[@var{format1}][,@var{format2}]
+Force the compressed formats given. Any of @var{format1} or
+@var{format2} may be omitted and the corresponding format will be
+automatically detected. Valid values for @var{format} are @samp{bz2},
+@samp{gz}, @samp{lz}, and @samp{xz}. 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
+@var{file1} and @var{file2} must be given. Other names won't be tried.
+
+@item -p
+@itemx --show-c-function
+Show which C function each change is in.
+
+@item -q
+@itemx --brief
+Output only whether files differ.
+
+@item -s
+@itemx --report-identical-files
+Report when two files are identical.
+
+@item -t
+@itemx --expand-tabs
+Expand tabs to spaces in output.
+
+@item -T
+@itemx --initial-tab
+Make tabs line up by prepending a tab.
+
+@item -u
+Use the unified output format.
+
+@item -U @var{n}
+@itemx --unified=@var{n}
+Same as -u but use @var{n} lines of context.
+
+@item -w
+@itemx --ignore-all-space
+Ignore all white space.
+
+@end table
+
+
+@node Zgrep
+@chapter Zgrep
+@cindex 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 @samp{-}, 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:
+
+@example
+zgrep [@var{options}] @var{pattern} [@var{files}]
+@end example
+
+@noindent
+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):
+
+@table @code
+@item -a
+@itemx --text
+Treat all files as text.
+
+@item -A @var{n}
+@itemx --after-context=@var{n}
+Print @var{n} lines of trailing context.
+
+@item -b
+@itemx --byte-offset
+Print the byte offset of each line.
+
+@item -B @var{n}
+@itemx --before-context=@var{n}
+Print @var{n} lines of leading context.
+
+@item -c
+@itemx --count
+Only print a count of matching lines per file.
+
+@item -C @var{n}
+@itemx --context=@var{n}
+Print @var{n} lines of output context.
+
+@item --color[=@var{when}]
+Show matched strings in color. @var{when} is @samp{never}, @samp{always},
+or @samp{auto}.
+
+@item -e @var{pattern}
+@itemx --regexp=@var{pattern}
+Use @var{pattern} as the pattern to match.
+
+@item -E
+@itemx --extended-regexp
+Treat @var{pattern} as an extended regular expression.
+
+@item -f @var{file}
+@itemx --file=@var{file}
+Obtain patterns from @var{file}, one per line.@*
+When searching in several files at once, command substitution can be
+used with @samp{-e} to read @var{file} only once, for example if
+@var{file} is not a regular file:
+@w{@samp{zgrep -e "$(cat @var{file})" file1.lz file2.gz}}
+
+@item -F
+@itemx --fixed-strings
+Treat @var{pattern} as a set of newline-separated strings.
+
+@item -h
+@itemx --no-filename
+Suppress the prefixing of file names on output when multiple files are
+searched.
+
+@item -H
+@itemx --with-filename
+Print the file name for each match.
+
+@item -i
+@itemx --ignore-case
+Ignore case distinctions.
+
+@item -I
+Ignore binary files.
+
+@item -l
+@itemx --files-with-matches
+Only print names of files containing at least one match.
+
+@item -L
+@itemx --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.
+
+@item -m @var{n}
+@itemx --max-count=@var{n}
+Stop after @var{n} matches.
+
+@item -n
+@itemx --line-number
+Prefix each matched line with its line number in the input file.
+
+@item -o
+@itemx --only-matching
+Show only the part of matching lines that actually matches @var{pattern}.
+
+@item -O @var{format}
+@itemx --force-format=@var{format}
+Force the compressed format given. Valid values for @var{format} are
+@samp{bz2}, @samp{gz}, @samp{lz}, and @samp{xz}. 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.
+
+@item -q
+@itemx --quiet
+Suppress all messages. Exit immediately with zero status if any match is
+found, even if an error was detected.
+
+@item -r
+@itemx --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.
+
+@item -R
+@itemx --dereference-recursive
+For each directory operand, read and process all files in that directory,
+recursively, following all symbolic links.
+
+@item -s
+@itemx --no-messages
+Suppress error messages about nonexistent or unreadable files.
+
+@item -v
+@itemx --invert-match
+Select non-matching lines.
+
+@item --verbose
+Verbose mode. Show error messages.
+
+@item -w
+@itemx --word-regexp
+Match only whole words.
+
+@item -x
+@itemx --line-regexp
+Match only whole lines.
+
+@end table
+
+
+@node Ztest
+@chapter Ztest
+@cindex ztest
+
+ztest verifies the integrity of the compressed files specified.
+Uncompressed files are ignored. If a file is specified as @samp{-}, 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.
+
+Note that error detection in the xz format is broken. First, some xz
+files lack integrity information. Second, not all xz decompressors can
+@uref{http://www.nongnu.org/lzip/xz_inadequate.html#fragmented,,verify the integrity}
+of all xz files. Third, section 2.1.1.2 'Stream Flags' of the
+@uref{http://tukaani.org/xz/xz-file-format.txt,,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.
+@c We can only hope that xz is soon abandoned.
+
+The format for running ztest is:
+
+@example
+ztest [@var{options}] [@var{files}]
+@end example
+
+@noindent
+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:
+
+@table @code
+@item -O @var{format}
+@itemx --force-format=@var{format}
+Force the compressed format given. Valid values for @var{format} are
+@samp{bz2}, @samp{gz}, @samp{lz}, and @samp{xz}. 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, @samp{--force-format=gz} can test gzipped (.gz) and
+compress'd (.Z) files if the compressor used is GNU gzip.
+
+@item -q
+@itemx --quiet
+Quiet operation. Suppress all messages.
+
+@item -r
+@itemx --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.
+
+@item -R
+@itemx --dereference-recursive
+For each directory operand, read and process all files in that directory,
+recursively, following all symbolic links.
+
+@item -v
+@itemx --verbose
+Verbose mode. Show the verify status for each file processed.@*
+Further -v's increase the verbosity level.
+
+@end table
+
+
+@node Zupdate
+@chapter Zupdate
+@cindex zupdate
+
+zupdate recompresses files from bzip2, gzip, and xz 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 @samp{--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 @samp{--force} and @samp{--keep}, as in
+@w{@samp{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:@*
+@samp{.bz2}, @samp{.gz}, or @samp{.xz}, which are recompressed to
+@samp{.lz};@*
+@samp{.tbz}, @samp{.tbz2}, @samp{.tgz}, or @samp{.txz}, which are
+recompressed to @samp{.tlz}.@*
+Keeping the combined extensions (@samp{.tgz} --> @samp{.tlz}) may be useful
+when recompressing Slackware packages, for example.
+
+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 @samp{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:
+
+@example
+zupdate [@var{options}] [@var{files}]
+@end example
+
+@noindent
+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:
+
+@table @code
+@item -f
+@itemx --force
+Don't skip a file for which a lzip compressed version already exists.
+@samp{--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.
+
+@item -k
+@itemx --keep
+Keep (don't delete) the input file after comparing it with the lzip file.
+
+@item -l
+@itemx --lzip-verbose
+Pass one option @samp{-v} to the lzip compressor so that it shows the
+compression ratio for each file processed. Using lzip 1.15 or newer, a
+second @samp{-l} shows the progress of compression. Use it together with
+@samp{-v} to see the name of the file.
+
+@item -q
+@itemx --quiet
+Quiet operation. Suppress all messages.
+
+@item -r
+@itemx --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.
+
+@item -R
+@itemx --dereference-recursive
+For each directory operand, read and process all files in that directory,
+recursively, following all symbolic links.
+
+@item -v
+@itemx --verbose
+Verbose mode. Show the files being processed. A second @samp{-v} also
+shows the files being ignored.
+
+@item -0 .. -9
+Set the compression level of lzip. By default zupdate passes @samp{-9} to
+lzip. Custom compression options can be passed to lzip with the option
+@samp{--lz}. For example @w{@samp{--lz='lzip -9 -s64MiB'}}.
+
+@end table
+
+
+@node Problems
+@chapter Reporting bugs
+@cindex bugs
+@cindex getting help
+
+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
+@email{zutils-bug@@nongnu.org}. Include the version number, which you can
+find by running @w{@samp{zupdate --version}}.
+
+
+@node Concept index
+@unnumbered Concept index
+
+@printindex cp
+
+@bye