dvhtool(1M)                                                        dvhtool(1M)


NAME
     dvhtool - modify and obtain disk volume header information

SYNOPSIS
     dvhtool [-v [creat unix_file dvh_file]
          [add unix_file dvh_file] [delete dvh_file]
          [get dvh_file unix_file] [list]] [header_filename]

DESCRIPTION
     dvhtool is used to copy files to and from the volume header of disks.
     Formerly it had other functions also, but these have long been deprecated
     and have been removed.

     The disk volume header consists of two main parts:  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.

     You must be superuser to use dvhtool.

     Invoked with no arguments (or just a volume header name,
     header_filename), dvhtool allows you to examine and modify the disk
     volume header on the root drive interactively.  The read command prompts
     for the name of the device file for the volume header to be worked on.
     This can 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 write command writes the possibly modified volume header to the
     device.

     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 command-line arguments.

     -v   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.

     creat
          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.

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


     delete
          Removes the entry named dvh_file, if it exists, from the volume
          directory.

     get  Copies the requested file from the volume header to the filesystem.

     list Lists the current volume directory contents.

SEE ALSO
     fx(1M), prtvtoc(1M), vh(7M).

NOTE
     Several megabytes 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.


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