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       hdfed - edit the contents of an HDF File


       hdfed [-nobackup] [-batch] hdf_file


       hdfed allows experienced HDF users to manipulate the elements of an HDF
       file. These manipulations include

       *      Selecting groups and showing information about them.

       *      Dumping group information to output files.

       *      Writing group data to output files.

       *      Deleting groups from HDF files.

       *      Inserting groups in HDF files.

       *      Replacing elements of HDF files.

       *      Editing the labels and descriptions of any  element  in  an  HDF

       hdfed  is designed primarily for users who need to know about HDF files
       at the level of individual data elements. It is not designed to provide
       a  comprehensive high-level view of the contents of an HDF file - other
       tools and utilities should be used for that purpose. To use  hdfed  one
       should  be  familiar  with the components of an HDF file covered in the
       HDF Specifications manual.

       The hdfed utility is loosely modeled on ed(1), the  UNIX  line  editor.
       When  hdfed  is  invoked, it prompts the user for commands, as does ed.
       Also, basic command syntax and description information is available  to
       the  user  through  hdfed.  The  most common hdfed commands are used to
       control the position in the HDF file and the format of the  information

       The  initial  view  of  the  file  under  hdfed  consists  of  a set of
       tag/reference number pairs. Although hdfed allows modification of  tags
       and  reference numbers within strict constraints, it will not allow the
       user to arbitrarily modify binary data in the file.

       The following terms and concepts must be understood  in  order  to  use
       hdfed  correctly  and  will  be  used in the following discussion about

       *      The data object or object refers to an HDF data object  and  the
              data  descriptor of that object. (i.e., tags, reference numbers,
              offsets, or lengths.)

       *      The data or data element refers to  the  record  that  the  data
              descriptor  points to. For a precise definition of the data that
              is associated with a given tag consult  the  HDF  Specifications
              and  Developer’s  Guide  v3.2  from  the  HDF  WWW  home page at

       *      The group refers to a predefined collection of data objects that
              correspond  to  a  particular application. For example, a raster
              image group refers to the collection of objects that are used to
              store all of the information in a raster image set.

       Once an HDF file has been opened by hdfed, the following operations can
       be performed on the data file, among others:

       *      Select an HDF object to examine more closely.

       *      Move forward or backward within the HDF file.

       *      Get information about an object. (tag, reference  number,  size,

       *      Display a raster image using the ICR protocol.

       *      Display the contents of any object.

       *      Delete an object.

       *      Annotate an object with a label or description.

       *      Write an object to a second HDF file.

       *      Write data elements in binary form to a non-HDF file.

       *      Close the file and exit, or open a new file.

       hdfed  commands  are  documented in the Users Guide section on Command-
       line Utilities.


              Make no backup file. If this option is omitted, a backup file is
              automatically created.

       -batch Input  to  hdfed  is  a  stream  of  hdfed commands, rather than
              interactively.  The -batch  flag  is  useful  when  a  group  of
              commonly-used  commands are included in a UNIX shell script. The
              following is an example of such a  script,  using  the  C-shell,
              that lists information about the groups in a specified HDF file.

                      #!/bin/csh -f
                      set file=$1
                      hdfed -batch $file -nobackup << EOF
                      info -all group $*
                      echo ""

       -help  Output usage information, as well as a quick list of the  hdfedj


       hdf(5),  ed(1),  The  HDF  Users  Guide:  /usr/share/doc/libhdf4g/html-

                               October 31, 1999