DVHTOOL(1M)                                                        DVHTOOL(1M)

NAME
     dvhtool - modify and obtain disk volume header information

SYNOPSIS
     /sbin/dvhtool [-b [ list ] [bootfile [rootpart [swappart]]]]
             [-v [creat unix_file dvh_file]
             [add unix_file dvh_file] [delete dvh_file]
             [get dvh_file unix_file] [list]] [header_filename]

DESCRIPTION
     Dvhtool allows modification of the disk volume header information, a
     block located at the beginning of all disk media. The disk volume header
     consists of three main parts:  the device parameters, the partition
     table, and the volume directory.  The volume directory is used to locate
     files kept in the volume header area of the disk for standalone use.  The
     partition table describes the logical device partitions.  The device
     parameters describe the specifics of a particular disk drive.

     Note that it is necessary to be superuser in order to use dvhtool.

     Invoked with no arguments (or just a volume header name), dvhtool allows
     the user to interactively examine and modify the disk volume header on
     the root drive.  The read command prompts for the name of the device file
     for the volume header to be worked on.  This may be /dev/rvh for the
     header of the root disk, or the header name of another disk in the
     /dev/rdsk directory.  See vh(7m).  It then reads the volume header from
     the specified device.
     The vd, pt, and dp commands first list their respective portions of the
     volume header and then prompt for modifications.  The write command
     writes the possibly modified volume header to the device.

     Note: use of dvhtool for changing partitions and parameters is not
     recommended. Parameters and partitions should be manipulated with fx(1m).

     Invoked with arguments, dvhtool reads the volume header, performs the
     specified operations, and then writes the volume header.  If no
     header_filename is specified on the command line, /dev/rvh is used.

     The following describes dvhtool's command line arguments.

     The -b flag allows you to set the current bootfile, root, and swap
     partitions. The list option displays their current settings.

     The -v flag provides five options for modifying and listing the contents
     of the volume directory information in the disk volume header: create,
     add, delete, get, and list.

     The creat option allows creation of a volume directory entry with the
     name dvh_file and the contents of unix_file. If an entry already exists
     with the name dvh_file, it is overwritten with the new contents.

                                                                        Page 1

DVHTOOL(1M)                                                        DVHTOOL(1M)

     The add option adds a volume directory entry with the name dvh_file and
     the contents of unix_file. Unlike the creat option, the add options will
     not overwrite an existing entry.

     The delete option removes the entry named dvh_file, if it exists, from
     the volume directory.

     The get option copies the requested file from the volume header to the
     file system.

     The list option lists the current volume directory contents.

SEE ALSO
     vh(7m)
     fx(1m)

NOTE
     Several Mbytes of disk space may be required in the /tmp directory when
     creating or adding files if the free space in the volume header is
     fragmented.  This also makes dvhtool run much slower, since all files
     must then be copied to /tmp, and then back to the volume header.

                                                                        Page 2