doc: fix order of du options in usage and texinfo manual

* src/du.c (usage): Bring options into alphabetical order.
* doc/coreutils.texi (du invocation): Likewise.
Furthermore, use the @itemx macro for the long options
--max-depth and --threshold instead of @item.

doc/coreutils.texi

@@ -10887,6 +10887,8 @@ The program accepts the following options.  Also see @ref{Common options}.
 
 @table @samp
 
+@optNull{du}
+
 @item -a
 @itemx --all
 @opindex -a
@@ -10912,12 +10914,6 @@ dd bs=1 seek=2GiB if=/dev/null of=big
 has an apparent size of 2 GiB, yet on most modern
 systems, it actually uses almost no disk space.
 
-@item -b
-@itemx --bytes
-@opindex -b
-@opindex --bytes
-Equivalent to @code{--apparent-size --block-size=1}.
-
 @item -B @var{size}
 @itemx --block-size=@var{size}
 @opindex -B
@@ -10926,6 +10922,12 @@ Equivalent to @code{--apparent-size --block-size=1}.
 Scale sizes by @var{size} before printing them (@pxref{Block size}).
 For example, @option{-BG} prints sizes in units of 1,073,741,824 bytes.
 
+@item -b
+@itemx --bytes
+@opindex -b
+@opindex --bytes
+Equivalent to @code{--apparent-size --block-size=1}.
+
 @item -c
 @itemx --total
 @opindex -c
@@ -10944,15 +10946,24 @@ Does not affect other symbolic links.  This is helpful for finding
 out the disk usage of directories, such as @file{/usr/tmp}, which
 are often symbolic links.
 
+@item -d @var{depth}
+@itemx --max-depth=@var{depth}
+@opindex -d @var{depth}
+@opindex --max-depth=@var{depth}
+@cindex limiting output of @command{du}
+Show the total for each directory (and file if --all) that is at
+most MAX_DEPTH levels down from the root of the hierarchy.  The root
+is at level 0, so @code{du --max-depth=0} is equivalent to @code{du -s}.
+
 @c --files0-from=FILE
 @filesZeroFromOption{du,, with the @option{--total} (@option{-c}) option}
 
-@optHumanReadable
-
 @item -H
 @opindex -H
 Equivalent to @option{--dereference-args} (@option{-D}).
 
+@optHumanReadable
+
 @item -k
 @opindex -k
 @cindex kibibytes for file sizes
@@ -10960,14 +10971,6 @@ Print sizes in 1024-byte blocks, overriding the default block size
 (@pxref{Block size}).
 This option is equivalent to @option{--block-size=1K}.
 
-@item -l
-@itemx --count-links
-@opindex -l
-@opindex --count-links
-@cindex hard links, counting in @command{du}
-Count the size of all files, even if they have appeared already (as a
-hard link).
-
 @item -L
 @itemx --dereference
 @opindex -L
@@ -10977,6 +10980,14 @@ Dereference symbolic links (show the disk space used by the file
 or directory that the link points to instead of the space used by
 the link).
 
+@item -l
+@itemx --count-links
+@opindex -l
+@opindex --count-links
+@cindex hard links, counting in @command{du}
+Count the size of all files, even if they have appeared already (as a
+hard link).
+
 @item -m
 @opindex -m
 @cindex mebibytes for file sizes
@@ -10992,25 +11003,6 @@ This option is equivalent to @option{--block-size=1M}.
 For each symbolic links encountered by @command{du},
 consider the disk space used by the symbolic link.
 
-@item -d @var{depth}
-@item --max-depth=@var{depth}
-@opindex -d @var{depth}
-@opindex --max-depth=@var{depth}
-@cindex limiting output of @command{du}
-Show the total for each directory (and file if --all) that is at
-most MAX_DEPTH levels down from the root of the hierarchy.  The root
-is at level 0, so @code{du --max-depth=0} is equivalent to @code{du -s}.
-
-@optNull{du}
-
-@optSi
-
-@item -s
-@itemx --summarize
-@opindex -s
-@opindex --summarize
-Display only a total for each argument.
-
 @item -S
 @itemx --separate-dirs
 @opindex -S
@@ -11022,8 +11014,16 @@ With @option{--separate-dirs}, the size reported for a directory name,
 @var{d}, is merely the @code{stat.st_size}-derived size of the directory
 entry, @var{d}.
 
+@optSi
+
+@item -s
+@itemx --summarize
+@opindex -s
+@opindex --summarize
+Display only a total for each argument.
+
 @item -t @var{size}
-@item --threshold=@var{size}
+@itemx --threshold=@var{size}
 @opindex -t
 @opindex --threshold
 Exclude entries based on a given @var{size} (@pxref{Block size}).
@@ -11124,21 +11124,6 @@ the newline and any later characters are ignored; if @env{TIME_STYLE}
 begins with @samp{posix-} the @samp{posix-} is ignored; and if
 @env{TIME_STYLE} is @samp{locale} it is ignored.
 
-@item -x
-@itemx --one-file-system
-@opindex -x
-@opindex --one-file-system
-@cindex one file system, restricting @command{du} to
-Skip directories that are on different file systems from the one that
-the argument being processed is on.
-
-@item --exclude=@var{pattern}
-@opindex --exclude=@var{pattern}
-@cindex excluding files from @command{du}
-When recursing, skip subdirectories or files matching @var{pattern}.
-For example, @code{du --exclude='*.o'} excludes files whose names
-end in @samp{.o}.
-
 @item -X @var{file}
 @itemx --exclude-from=@var{file}
 @opindex -X @var{file}
@@ -11148,6 +11133,21 @@ Like @option{--exclude}, except take the patterns to exclude from @var{file},
 one per line.  If @var{file} is @samp{-}, take the patterns from standard
 input.
 
+@item --exclude=@var{pattern}
+@opindex --exclude=@var{pattern}
+@cindex excluding files from @command{du}
+When recursing, skip subdirectories or files matching @var{pattern}.
+For example, @code{du --exclude='*.o'} excludes files whose names
+end in @samp{.o}.
+
+@item -x
+@itemx --one-file-system
+@opindex -x
+@opindex --one-file-system
+@cindex one file system, restricting @command{du} to
+Skip directories that are on different file systems from the one that
+the argument being processed is on.
+
 @end table
 
 @cindex NFS mounts from BSD to HP-UX

src/du.c

@@ -278,6 +278,7 @@ Summarize disk usage of each FILE, recursively for directories.\n\
       emit_mandatory_arg_note ();
 
       fputs (_("\
+  -0, --null            end each output line with 0 byte rather than newline\n\
   -a, --all             write counts for all files, not just directories\n\
       --apparent-size   print apparent sizes, rather than disk usage; although\
 \n\
@@ -293,6 +294,10 @@ Summarize disk usage of each FILE, recursively for directories.\n\
   -c, --total           produce a grand total\n\
   -D, --dereference-args  dereference only symlinks that are listed on the\n\
                           command line\n\
+  -d, --max-depth=N     print the total for a directory (or file, with --all)\n\
+                          only if it is N or fewer levels below the command\n\
+                          line argument;  --max-depth=0 is the same as\n\
+                          --summarize\n\
 "), stdout);
       fputs (_("\
       --files0-from=F   summarize disk usage of the NUL-terminated file\n\
@@ -301,32 +306,22 @@ Summarize disk usage of each FILE, recursively for directories.\n\
   -H                    equivalent to --dereference-args (-D)\n\
   -h, --human-readable  print sizes in human readable format (e.g., 1K 234M 2G)\
 \n\
-      --si              like -h, but use powers of 1000 not 1024\n\
 "), stdout);
       fputs (_("\
   -k                    like --block-size=1K\n\
+  -L, --dereference     dereference all symbolic links\n\
   -l, --count-links     count sizes many times if hard linked\n\
   -m                    like --block-size=1M\n\
 "), stdout);
       fputs (_("\
-  -L, --dereference     dereference all symbolic links\n\
   -P, --no-dereference  don't follow any symbolic links (this is the default)\n\
-  -0, --null            end each output line with 0 byte rather than newline\n\
   -S, --separate-dirs   do not include size of subdirectories\n\
+      --si              like -h, but use powers of 1000 not 1024\n\
   -s, --summarize       display only a total for each argument\n\
 "), stdout);
       fputs (_("\
-  -x, --one-file-system    skip directories on different file systems\n\
-  -X, --exclude-from=FILE  exclude files that match any pattern in FILE\n\
-      --exclude=PATTERN    exclude files that match PATTERN\n\
-  -d, --max-depth=N     print the total for a directory (or file, with --all)\n\
-                          only if it is N or fewer levels below the command\n\
-                          line argument;  --max-depth=0 is the same as\n\
-                          --summarize\n\
   -t, --threshold=SIZE  exclude entries smaller than SIZE if positive,\n\
                           or entries greater than SIZE if negative\n\
-"), stdout);
-      fputs (_("\
       --time            show time of the last modification of any file in the\n\
                           directory, or any of its subdirectories\n\
       --time=WORD       show time as WORD instead of modification time:\n\
@@ -334,6 +329,11 @@ Summarize disk usage of each FILE, recursively for directories.\n\
       --time-style=STYLE  show times using style STYLE:\n\
                           full-iso, long-iso, iso, +FORMAT\n\
                           FORMAT is interpreted like 'date'\n\
+"), stdout);
+      fputs (_("\
+  -X, --exclude-from=FILE  exclude files that match any pattern in FILE\n\
+      --exclude=PATTERN    exclude files that match PATTERN\n\
+  -x, --one-file-system    skip directories on different file systems\n\
 "), stdout);
       fputs (HELP_OPTION_DESCRIPTION, stdout);
       fputs (VERSION_OPTION_DESCRIPTION, stdout);