Tweak mdconfig(8) manual page, in particular revise the EXAMPLES

section.  This removes stuff that doesn't really belong there,
and simplifies examples for the basic operations.

Reviewed by:	wblock@
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D3198

sbin/mdconfig/mdconfig.8

@@ -37,12 +37,12 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 30, 2013
+.Dd August 6, 2015
 .Dt MDCONFIG 8
 .Os
 .Sh NAME
 .Nm mdconfig
-.Nd configure and enable memory disks
+.Nd create and control memory disks
 .Sh SYNOPSIS
 .Nm
 .Fl a
@@ -75,7 +75,7 @@
 .Sh DESCRIPTION
 The
 .Nm
-utility configures and enables
+utility creates and controls
 .Xr md 4
 devices.
 .Pp
@@ -103,7 +103,7 @@ If the
 .Fl o Cm reserve
 option is not set, creating and filling a large
 malloc-backed memory disk is a very easy way to
-panic a system.
+panic the system.
 .It Cm vnode
 A file specified with
 .Fl f Ar file
@@ -164,7 +164,9 @@ or
 .Cm t
 which
 denotes byte, kilobyte, megabyte, gigabyte and terabyte respectively.
-The
+When used without the
+.Fl r
+option, the
 .Fl a
 and
 .Fl t Ar swap
@@ -206,6 +208,11 @@ Enable/disable compression features to reduce memory usage.
 .It Oo Cm no Oc Ns Cm force
 Disable/enable extra sanity checks to prevent the user from doing something
 that might adversely affect the system.
+This can be used with the
+.Fl u
+flag to forcibly destroy an
+.Xr md 4
+disk that is still in use.
 .It Oo Cm no Oc Ns Cm readonly
 Enable/disable readonly mode.
 .El
@@ -227,66 +234,58 @@ is provided for convenience as an abbreviation of
 .Fl t Ar vnode
 .Fl f Ar file .
 .Sh EXAMPLES
-Create a 4 megabyte
-.Xr malloc 9
-backed memory disk.
-The name of the allocated unit will be printed on stdout, such as
-.Dq Li md3 :
-.Pp
-.Dl mdconfig -a -t malloc -s 4m
-.Pp
-Create a disk named
-.Pa /dev/md4
-with
+Create a disk with
 .Pa /tmp/boot.flp
-as backing storage:
+as backing storage.
+The name of the allocated unit will be printed on stdout, such as
+.Dq Li md0 :
+.Bd -literal -offset indent
+mdconfig /tmp/boot.flp
+.Ed
 .Pp
-.Dl mdconfig -a -t vnode -f /tmp/boot.flp -u md4
+Create a 1 gigabyte swap backed memory disk named
+.Dq Li md3 :
+.Bd -literal -offset indent
+mdconfig -s 1g -u md3
+.Ed
 .Pp
 Detach and free all resources used by
-.Pa /dev/md4 :
+.Pa /dev/md3 :
+.Bd -literal -offset indent
+mdconfig -du md3
+.Ed
 .Pp
-.Dl mdconfig -d -u md4
+Show detailed information on current memory disks:
+.Bd -literal -offset indent
+mdconfig -lv
+.Ed
 .Pp
-Create a 128MByte swap backed disk, initialize an
+Resize the
+.Dq Li md3
+memory disk to 2 gigabytes:
+.Bd -literal -offset indent
+mdconfig -rs 2g -u md3
+.Ed
+.Pp
+Create a 1 gigabyte swap backed disk, initialize an
 .Xr ffs 7
 file system on it, and mount it on
 .Pa /tmp :
 .Bd -literal -offset indent
-mdconfig -a -t swap -s 128M -u md10
+mdconfig -s 1g -u md10
 newfs -U /dev/md10
 mount /dev/md10 /tmp
 chmod 1777 /tmp
 .Ed
 .Pp
-Create a 5MB file-backed disk
-.Po Fl a
-and
-.Fl t Ar vnode
-are implied
-.Pc :
-.Bd -literal -offset indent
-dd if=/dev/zero of=somebackingfile bs=1k count=5k
-mdconfig -f somebackingfile -u md0
-bsdlabel -w md0 auto
-newfs md0c
-mount /dev/md0c /mnt
-.Ed
-.Pp
-Create an
+Create a memory disk out of an ISO 9660 CD image file,
+using the first available
 .Xr md 4
-device out of an ISO 9660 CD image file
-.Po Fl a
-and
-.Fl t Ar vnode
-are implied
-.Pc , using the first available
-.Xr md 4
-device, and then mount the new memory disk:
+device, and then mount it:
 .Bd -literal -offset indent
 mount -t cd9660 /dev/`mdconfig -f cdimage.iso` /mnt
-.Pp
 .Ed
+.Pp
 Create a file-backed device from a hard disk image that begins
 with 512K of raw header information.
 .Xr gnop 8
@@ -294,7 +293,7 @@ is used to skip over the header information, positioning
 .Pa md1.nop
 to the start of the filesystem in the image.
 .Bd -literal -offset indent
-mdconfig -f diskimage.img -u md1
+mdconfig -u md1 -f diskimage.img
 gnop create -o 512K md1
 mount /dev/md1.nop /mnt
 .Ed