docs/162438: du(1) man page improvements

[Alexander Best]

here's another revised version of my patch. this now also includes changes
to du.c:usage() to reflect the man page changes.

cheers.
alex
-------------- next part --------------
diff --git a/usr.bin/du/du.1 b/usr.bin/du/du.1
index ef8b5ac..66bdefe 100644
--- a/usr.bin/du/du.1
+++ b/usr.bin/du/du.1
@@ -28,7 +28,7 @@
 .\"	@(#)du.1	8.2 (Berkeley) 4/1/94
 .\" $FreeBSD$
 .\"
-.Dd November 6, 2008
+.Dd November 11, 2011
 .Dt DU 1
 .Os
 .Sh NAME
@@ -36,15 +36,12 @@
 .Nd display disk usage statistics
 .Sh SYNOPSIS
 .Nm
-.Op Fl A
+.Op Fl Achklmnx
 .Op Fl H | L | P
-.Op Fl a | s | d Ar depth | Fl t Ar threshold
-.Op Fl c
-.Op Fl l
-.Op Fl h | k | m | B Ar blocksize
-.Op Fl n
-.Op Fl x
+.Op Fl a | s | d Ar depth
+.Op Fl B Ar blocksize
 .Op Fl I Ar mask
+.Op Fl t Ar threshold
 .Op Ar
 .Sh DESCRIPTION
 The
@@ -65,7 +62,9 @@ Calculate block counts in
 .Ar blocksize
 byte blocks.
 This is different from the
-.Fl k, m
+.Fl h, k
+and
+.Fl  m
 options or setting
 .Ev BLOCKSIZE
 and gives an estimate of how much space the examined file hierarchy would
@@ -79,48 +78,31 @@ is rounded up to the next multiple of 512.
 .It Fl H
 Symbolic links on the command line are followed, symbolic links in file
 hierarchies are not followed.
-.It Fl L
-Symbolic links on the command line and in file hierarchies are followed.
 .It Fl I Ar mask
 Ignore files and directories matching the specified
 .Ar mask .
+.It Fl L
+Symbolic links on the command line and in file hierarchies are followed.
 .It Fl P
 No symbolic links are followed.
 This is the default.
 .It Fl a
 Display an entry for each file in a file hierarchy.
-.It Fl h
-"Human-readable" output.
-Use unit suffixes: Byte, Kilobyte, Megabyte,
-Gigabyte, Terabyte and Petabyte.
-.It Fl r
-Generate messages about directories that cannot be read, files
-that cannot be opened, and so on.
-This is the default case.
-This option exists solely for conformance with
-.St -xpg4 .
-.It Fl s
-Display an entry for each specified file.
-(Equivalent to
-.Fl d Li 0 )
-.It Fl t Ar threshold
-Display only entries for which size exceeds
-.Ar threshold .
-If
-.Ar threshold
-is negative, display only entries for which size is less than the absolute
-value of
-.Ar threshold .
+.It Fl c
+Display a grand total.
 .It Fl d Ar depth
 Display an entry for all files and directories
 .Ar depth
 directories deep.
-.It Fl c
-Display a grand total.
+.It Fl h
+.Dq Human-readable
+output.
+Use unit suffixes: Byte, Kilobyte, Megabyte,
+Gigabyte, Terabyte and Petabyte.
 .It Fl k
 Display block counts in 1024-byte (1-Kbyte) blocks.
 .It Fl l
-If a file has multiple hard links, count its size many times.
+If a file has multiple hard links, count its size multiple times.
 The default behavior of
 .Nm
 is to count files with multiple hard links only once.
@@ -136,6 +118,24 @@ Ignore files and directories with user
 flag
 .Pq Dv UF_NODUMP
 set.
+.It Fl r
+Generate messages about directories that cannot be read, files
+that cannot be opened, and so on.
+This is the default case.
+This option exists solely for conformance with
+.St -xpg4 .
+.It Fl s
+Display an entry for each specified file.
+(Equivalent to
+.Fl d Li 0 )
+.It Fl t Ar threshold
+Display only entries for which size exceeds
+.Ar threshold .
+If
+.Ar threshold
+is negative, display only entries for which size is less than the absolute
+value of
+.Ar threshold .
 .It Fl x
 File system mount points are not traversed.
 .El
@@ -152,25 +152,32 @@ If either the
 .Fl H
 or
 .Fl L
-options are specified, storage used by any symbolic links which are
-followed is not counted or displayed.
+option is specified, storage used by any symbolic links which are
+followed is not counted (or displayed).
+.Pp
+The
+.Fl h, k
+and
+.Fl m
+options all override each other; the last one specified determines
+the block counts used.
 .Sh ENVIRONMENT
 .Bl -tag -width BLOCKSIZE
 .It Ev BLOCKSIZE
 If the environment variable
 .Ev BLOCKSIZE
 is set, and the
-.Fl k, m
+.Fl h, k
 or
-.Fl h
+.Fl m
 options are not specified, the block counts will be displayed in units of
 that block size.
 If
 .Ev BLOCKSIZE
 is not set, and the
-.Fl k, m
+.Fl h, k
 or
-.Fl h
+.Fl m
 options are not specified, the block counts will be displayed in 512-byte
 blocks.
 .El
diff --git a/usr.bin/du/du.c b/usr.bin/du/du.c
index 5c670d4..2dfd05b 100644
--- a/usr.bin/du/du.c
+++ b/usr.bin/du/du.c
@@ -499,9 +499,8 @@ static void
 usage(void)
 {
 	(void)fprintf(stderr,
-		"usage: du [-A] [-H | -L | -P] [-a | -s | -d depth] [-c] "
-		"[-l] [-h | -k | -m | -B bsize] [-n] [-x] [-I mask] "
-		"[file ...]\n");
+		"usage: du [-Achklmnx] [-H | -L | -P] [-a | -s | -d depth] "
+		"[-B blocksize] [-I mask] [-t threshold] [file ...]\n");
 	exit(EX_USAGE);
 }