xzdiff, xzgrep, and xzmore: Rewrite the man pages.

The main reason is a kind of silly one:

xz-man.pot contains strings from all man pages in XZ Utils.
The man pages of xzdiff, xzgrep, and xzmore were under GPLv2
and the rest under 0BSD. Thus xz-man.pot contained strings
under two licences. po4a creates the translated man pages
from the combined 0BSD+GPLv2 xz-man.pot.

I haven't liked this mixing in xz-man.pot but the
Translation Project requires that all man pages must be
in the same .pot file. So a separate xz-man-gpl.pot
wasn't an option.

Since these man pages are short, rewriting them was quick enough.
Now xz-man.pot is entirely under 0BSD and marking the per-file
licenses is simpler.

As a bonus, some wording hopefully is now slightly better
although it's perhaps a matter of taste.

NOTE: In xzgrep.1, the EXIT STATUS section was written by me
in the commit d796b6d7fdb8b7238b277056cf9146cce25db604 so that's
why that section could be taken as is from the old xzgrep.1.

3 files changed, 173 insertions, 116 deletions

diff --git a/src/scripts/xzdiff.1 b/src/scripts/xzdiff.1
index 21824118..5f556072 100644
--- a/src/scripts/xzdiff.1
+++ b/src/scripts/xzdiff.1
@@ -1,66 +1,89 @@
-.\" SPDX-License-Identifier: GPL-2.0-or-later
+.\" SPDX-License-Identifier: 0BSD
 .\"
-.\" Original zdiff.1 for gzip: Jean-loup Gailly
+.\" Authors: Lasse Collin
+.\"          Jia Tan
 .\"
-.\" Modifications for XZ Utils: Lasse Collin
-.\"                             Andrew Dudman
+.\" (Note that this file is not based on gzip's zdiff.1.)
 .\"
-.TH XZDIFF 1 "2021-06-04" "Tukaani" "XZ Utils"
+.TH XZDIFF 1 "2024-02-12" "Tukaani" "XZ Utils"
 .SH NAME
 xzcmp, xzdiff, lzcmp, lzdiff \- compare compressed files
+.
 .SH SYNOPSIS
 .B xzcmp
-.RI [ cmp_options "] " file1 " [" file2 ]
+.RI [ option... ]
+.I file1
+.RI [ file2 ]
 .br
 .B xzdiff
-.RI [ diff_options "] " file1 " [" file2 ]
+\&...
 .br
 .B lzcmp
-.RI [ cmp_options "] " file1 " [" file2 ]
+\&...
 .br
 .B lzdiff
-.RI [ diff_options "] " file1 " [" file2 ]
+\&...
+.
 .SH DESCRIPTION
 .B xzcmp
 and
 .B xzdiff
-invoke
+compare uncompressed contents of two files.
+Uncompressed data and options are passed to
 .BR cmp (1)
 or
 .BR diff (1)
-on files compressed with
+unless
+.B \-\-help
+or
+.B \-\-version
+is specified.
+.PP
+If both
+.I file1
+and
+.I file2
+are specified, they can be uncompressed files or files in formats that
 .BR xz (1),
-.BR lzma (1),
 .BR gzip (1),
 .BR bzip2 (1),
 .BR lzop (1),
 or
-.BR zstd (1).
-All options specified are passed directly to
-.BR cmp (1)
-or
-.BR diff (1).
-If only one file is specified, then the files compared are
+.BR zstd (1)
+can decompress.
+The required decompression commands are determined from
+the filename suffixes of
 .I file1
-(which must have a suffix of a supported compression format) and
+and
+.IR file2 .
+A file with an unknown suffix is assumed to be either uncompressed
+or in a format that
+.BR xz (1)
+can decompress.
+.PP
+If only one filename is provided,
 .I file1
-from which the compression format suffix has been stripped.
-If two files are specified,
-then they are uncompressed if necessary and fed to
-.BR cmp (1)
-or
-.BR diff (1).
-The exit status from
-.BR cmp (1)
-or
-.BR diff (1)
-is preserved unless a decompression error occurs; then exit status is 2.
+must have a suffix of a supported compression format and the name for
+.I file2
+is assumed to be
+.I file1
+with the compression format suffix removed.
 .PP
-The names
+The commands
 .B lzcmp
 and
 .B lzdiff
 are provided for backward compatibility with LZMA Utils.
+.
+.SH EXIT STATUS
+If a decompression error occurs, the exit status is
+.BR 2 .
+Otherwise the exit status of
+.BR cmp (1)
+or
+.BR diff (1)
+is used.
+.
 .SH "SEE ALSO"
 .BR cmp (1),
 .BR diff (1),
@@ -68,11 +91,4 @@ are provided for backward compatibility with LZMA Utils.
 .BR gzip (1),
 .BR bzip2 (1),
 .BR lzop (1),
-.BR zstd (1),
-.BR zdiff (1)
-.SH BUGS
-Messages from the
-.BR cmp (1)
-or
-.BR diff (1)
-programs refer to temporary filenames instead of those specified.
+.BR zstd (1)
diff --git a/src/scripts/xzgrep.1 b/src/scripts/xzgrep.1
index 0ace8502..d60a0516 100644
--- a/src/scripts/xzgrep.1
+++ b/src/scripts/xzgrep.1
@@ -1,18 +1,18 @@
-.\" SPDX-License-Identifier: GPL-2.0-or-later
+.\" SPDX-License-Identifier: 0BSD
 .\"
-.\" Original zgrep.1 for gzip: Jean-loup Gailly
-.\"                            Charles Levert <charles@comm.polymtl.ca>
+.\" Authors: Lasse Collin
+.\"          Jia Tan
 .\"
-.\" Modifications for XZ Utils: Lasse Collin
+.\" (Note that this file is not based on gzip's zgrep.1.)
 .\"
-.TH XZGREP 1 "2022-07-19" "Tukaani" "XZ Utils"
+.TH XZGREP 1 "2024-02-12" "Tukaani" "XZ Utils"
 .SH NAME
-xzgrep \- search compressed files for a regular expression
+xzgrep \- search possibly-compressed files for patterns
+.
 .SH SYNOPSIS
 .B xzgrep
-.RI [ grep_options ]
-.RB [ \-e ]
-.I pattern
+.RI [ option... ]
+.RI [ pattern_list ]
 .RI [ file... ]
 .br
 .B xzegrep
@@ -29,54 +29,83 @@ xzgrep \- search compressed files for a regular expression
 .br
 .B lzfgrep
 \&...
+.
 .SH DESCRIPTION
 .B xzgrep
 invokes
 .BR grep (1)
-on
+on uncompressed contents of files.
+The formats of the
 .I files
-which may be either uncompressed or compressed with
+are determined from the filename suffixes.
+Any
+.I file
+with a suffix supported by
 .BR xz (1),
-.BR lzma (1),
 .BR gzip (1),
 .BR bzip2 (1),
 .BR lzop (1),
 or
-.BR zstd (1).
-All options specified are passed directly to
-.BR grep (1).
+.BR zstd (1)
+will be decompressed;
+all other files are assumed to be uncompressed.
 .PP
 If no
+.I files
+are specified or
 .I file
-is specified, then standard input is decompressed if necessary
-and fed to
-.BR grep (1).
-When reading from standard input,
-.BR gzip (1),
-.BR bzip2 (1),
-.BR lzop (1),
-and
-.BR zstd (1)
-compressed files are not supported.
+is
+.B \-
+then standard input is read.
+When reading from standard input, only files supported by
+.BR xz (1)
+are decompressed.
+Other files are assumed to be in uncompressed form already.
+.PP
+Most
+.I options
+of
+.BR grep (1)
+are supported.
+However, the following options are not supported:
+.IP "" 4
+.BR \-r ,
+.B \-\-recursive
+.IP "" 4
+.BR \-R ,
+.B \-\-dereference\-recursive
+.IP "" 4
+.BR \-d ,
+.BI \-\-directories= action
+.IP "" 4
+.BR \-Z ,
+.B \-\-null
+.IP "" 4
+.BR \-z ,
+.B \-\-null\-data
+.IP "" 4
+.BI \-\-include= glob
+.IP "" 4
+.BI \-\-exclude= glob
+.IP "" 4
+.BI \-\-exclude\-from= file
+.IP "" 4
+.BI \-\-exclude\-dir= glob
 .PP
-If
-.B xzgrep
-is invoked as
 .B xzegrep
-or
+is an alias for
+.BR "xzgrep \-E" .
 .B xzfgrep
-then
-.B grep \-E
-or
-.B grep \-F
-is used instead of
-.BR grep (1).
-The same applies to names
+is an alias for
+.BR "xzgrep \-F" .
+.PP
+The commands
 .BR lzgrep ,
 .BR lzegrep ,
 and
-.BR lzfgrep ,
-which are provided for backward compatibility with LZMA Utils.
+.B lzfgrep
+are provided for backward compatibility with LZMA Utils.
+.
 .SH EXIT STATUS
 .TP
 0
@@ -90,18 +119,19 @@ No errors occurred.
 >1
 One or more errors occurred.
 It is unknown if matches were found.
+.
 .SH ENVIRONMENT
 .TP
 .B GREP
-If the
+If
 .B GREP
-environment variable is set,
-.B xzgrep
-uses it instead of
-.BR grep (1),
+is set to a non-empty value,
+it is used instead of
+.BR "grep" ,
 .BR "grep \-E" ,
 or
 .BR "grep \-F" .
+.
 .SH "SEE ALSO"
 .BR grep (1),
 .BR xz (1),
diff --git a/src/scripts/xzmore.1 b/src/scripts/xzmore.1
index 8a402808..8099be35 100644
--- a/src/scripts/xzmore.1
+++ b/src/scripts/xzmore.1
@@ -1,52 +1,63 @@
-.\" SPDX-License-Identifier: GPL-2.0-or-later
+.\" SPDX-License-Identifier: 0BSD
 .\"
-.\" Original zdiff.1 for gzip: Jean-loup Gailly
-.\" Modifications for XZ Utils: Lasse Collin
+.\" Authors: Andrew Dudman
+.\"          Lasse Collin
 .\"
-.TH XZMORE 1 "2013-06-30" "Tukaani" "XZ Utils"
+.\" (Note that this file is based on xzless.1 instead of gzip's zmore.1.)
+.\"
+.TH XZMORE 1 "2024-02-12" "Tukaani" "XZ Utils"
 .SH NAME
 xzmore, lzmore \- view xz or lzma compressed (text) files
+.
 .SH SYNOPSIS
 .B xzmore
-.RI [ file... ]
+.RI [ file ...]
 .br
 .B lzmore
-.RI [ file... ]
+.RI [ file ...]
+.
 .SH DESCRIPTION
-.B  xzmore
-is a filter which allows examination of
+.B xzmore
+displays text from compressed files to a terminal using
+.BR more (1).
+Files supported by
 .BR xz (1)
-or
-.BR lzma (1)
-compressed text files one screenful at a time
-on a soft-copy terminal.
+are decompressed;
+other files are assumed to be in uncompressed form already.
+If no
+.I files
+are given,
+.B xzmore
+reads from standard input.
+See the
+.BR more (1)
+manual for the keyboard commands.
 .PP
-To use a pager other than the default
-.B more,
-set environment variable
-.B PAGER
-to the name of the desired program.
-The name
+Note that scrolling backwards might not be possible
+depending on the implementation of
+.BR more (1).
+This is because
+.B xzmore
+uses a pipe to pass the decompressed data to
+.BR more (1).
+.BR xzless (1)
+uses
+.BR less (1)
+which provides more advanced features.
+.PP
+The command
 .B lzmore
 is provided for backward compatibility with LZMA Utils.
+.
+.SH ENVIRONMENT
 .TP
-.BR e " or " q
-When the prompt \-\-More\-\-(Next file:
-.IR file )
-is printed, this command causes
-.B xzmore
-to exit.
-.TP
-.B s
-When the prompt \-\-More\-\-(Next file:
-.IR file )
-is printed, this command causes
-.B xzmore
-to skip the next file and continue.
-.PP
-For list of keyboard commands supported while actually viewing the
-content of a file, refer to manual of the pager you use, usually
+.B PAGER
+If
+.B PAGER
+is set,
+it's value is used as the pager instead of
 .BR more (1).
+.
 .SH "SEE ALSO"
 .BR more (1),
 .BR xz (1),