fscat_vxfs(1M)                                               fscat_vxfs(1M)




 NAME    [Toc]    [Back]
      fscat_vxfs: fscat - cat a VxFS file system

 SYNOPSIS    [Toc]    [Back]
      fscat [-F vxfs] [-f output-file] [-o offset] [-l length]
           [-b block_size] special

 DESCRIPTION    [Toc]    [Back]
      fscat provides an interface to a VxFS snapshot file system, similar to
      that provided by dd, invoked on the block or character special file of
      regular VxFS file systems.  fscat works when executed on the special
      device of any VxFS file system.

      On most VxFS file systems, the block or character special file for the
      file system provides access to a raw image of the file system to back
      up the file system to tape.  On a snapshot file system, access to the
      corresponding block or character special file provides little useful
      information.  fscat provides a stream of bytes representing the file
      system snapshot.  This datastream is written by default to standard
      output, although the -f output-file option can be used to specify
      another destination.  The datastream on standard output can be
      processed several ways, such as in a pipeline, or written to a tape.

      By default, the output is a stream of bytes that starts at the
      beginning of the file system and continues to the last byte.  On a
      snapshot file system, data is read from the file system using special
      ioctls on the mount point.  On other VxFS file systems, data is read
      from the specified special file.  Unless otherwise specified, data is
      written to standard output.

      All numbers entered as option arguments can have 0 as a prefix to
      indicate octal, or 0x as a prefix to indicate hexadecimal.  A b or B
      can be appended to indicate the value is in 512-byte blocks, a k or K
      to indicate the value is in kilobytes, an m or M to indicate the value
      is in megabytes, or a g or G to indicate the value is in gigabytes.
      An appended letter can be separated from the number by a space, in
      which case the letter and number should be enclosed in a set of
      quotes. For example:

           "512 b"

      All numbers entered as options must be in multiples of 512 bytes.  For
      example, a value of 5713 as an offset is rejected.

    Options    [Toc]    [Back]
      fscat recognizes the following options:

      -b block_size  Specify the output block size, in bytes.  block_size
                     must be less than or equal to 1 megabyte.





 Hewlett-Packard Company            - 1 -   HP-UX 11i Version 2: August 2003






 fscat_vxfs(1M)                                               fscat_vxfs(1M)




      -F vxfs        Specify the VxFS file system type.

      -f output-file Specify an output file in which to write the
                     datastream.

      -l length      Specify the transfer length, in bytes.  A length of 0
                     includes the remainder of the file system after the
                     specified offset.

      -o offset      Specify the starting offset in bytes.

    Operands    [Toc]    [Back]
      fscat recognizes the following operand:

           special        Name of the special device from which the VxFS
                          file system is accessed.

    Notes    [Toc]    [Back]
      Snapshot file systems are only available with the HP OnLineJFS
      product.

      A snapshot file system cannot be written to.

      A snapshot file system exists only as long as it is mounted; once
      unmounted, the special file no longer contains a snapshot file system.

      When fscat is run on a mounted VxFS snapshot, the content of free
      blocks (that is, blocks not allocated to any file or metadata) is
      undefined.  The content of free blocks can change after additional
      data is written to the primary (snapped) file system, but blocks
      associated with files always display the content they had when the
      snapshot was created.

      fscat does not work with Storage Checkpoints.

 SEE ALSO    [Toc]    [Back]
      dd(1), fs_vxfs(4), vxfsio(7).


 Hewlett-Packard Company            - 2 -   HP-UX 11i Version 2: August 2003