What are the HDF4 command line utilities?

the HDF command line utilities are application programs that can be executed by entering them at the command level, just like UNIX commands.

There are HDF utilities to: 

• analyze and view HDF files ('hdp' being one of the more useful tools)
• convert from one format to another
• manipulate HDF files

They provide capabilities for doing things with HDF files for which you would normally have to write your own program.

The hdp utility is one of the more useful HDF utilities. Following is a description of its function:

It provides quick information about the contents and data objects in an HDF file. It can list the contents of hdf files at various levels with different details. It can also dump the data of one or more objects in the file in binary or ASCII format.

The other utilities are: 

• gif2hdf — converts GIF image into HDF GR image.
• hdf24to8 — converts a 24-bit image into an 8-bit image
• h4cc — compiles an HDF4 C program
• h4fc — compiles an HDF4 F90 program
• h4redeploy — Updates paths in h4cc/h4fc after the HDF4 pre-compiled binaries have been installed in a new location
• hdf2gif — converts HDF GR image into GIF image.
• hdf2jpeg — converts hdf raster images to jpeg images
• hdf8to24 — converts an 8-bit image into a 24-bit image
• hdfcomp — re-compresses an 8-bit raster hdf file
• hdfed — hdf file editor - requires advanced knowledge of HDF.
• hdfimport — imports ASCII or binary data into HDF
• hdfls — lists basic information about an hdf file
• hdfpack — compacts an hdf file by eliminating unused space that has been created due to file modifications.
• hdftopal — extracts a palette from an hdf file
• hdftor8 — extracts 8-bit raster images and palettes from an hdf file
• hdfunpac — unpacks an HDF file by exporting the scientific data elements (DFTAG_SD) to external object elements
• hdiff — compares two HDF files and reports the differences
• hrepack — copies an HDF file to a new file with/without compression and/or chunking
• jpeg2hdf — converts jpeg images to hdf raster images
• paltohdf — converts a raw palette to hdf
• r8tohdf — converts 8-bit raster images to hdf
• ristosds — converts a raster image into an SDS
• vmake — creates vsets
• vshow — dumps out vsets from an hdf file

In addition, the netCDF utilities, ncdump and ncgen, COMPILED with the HDF library, are included.