hdfed - edit the contents of an HDF File
] [ -batch
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 file.
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
utility is loosely modeled on ed(1), the UNIX line editor. When
is invoked, it prompts the user for commands, as does ed. Also,
basic command syntax and description information is available to the user
. 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 hdfed
- 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
- 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 http://hdf.ncsa.uiuc.edu/.
- 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, label)
- 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.
commands are documented in the Users Guide section on Command-line
- Make no backup file. If this option is omitted, a backup file is
- 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.
hdfed -batch $file -nobackup << EOF
info -all group $*
- Output usage information, as well as a quick list of the hdfedj
(1), The HDF Users Guide: