usage: hrepack -i input -o output [-V] [-h] [-v] [-t 'comp_info'] [-c 'chunk_info'] [-f cfile] [-m size]
  -i input          input HDF File
  -o output         output HDF File
  [-V]              prints version of the HDF4 library and exits
  [-h]              prints this usage
  [-v]              verbose mode
  [-t 'comp_info']  compression type: 'comp_info' is a string with the format
		     <object list>:<type of compression><parameters>
		     <object list> is a comma separated list of object names
		        meaning apply compression only to those objects
		        '*' means all objects
		     <type of compression> can be:
		       RLE, for RLE compression
		       HUFF, for Huffman
		       GZIP, for gzip
		       JPEG, for JPEG (for images only)
		       SZIP, for szip
		       NONE, to uncompress
		     <parameters> is optional compression info
		       RLE, no parameter
		       HUFF, the skip-size
		       GZIP, the deflation level
		       JPEG, the quality factor
		       SZIP, pixels per block, compression mode (NN or EC)
  [-c 'chunk_info'] apply chunking. 'chunk_info' is a string with the format
		     <object list>:<chunk information>
		       <object list> is a comma separated list of object names
		         meaning apply chunking only to those objects
		         '*' means all objects
		       <chunk information> is the chunk size of each dimension:
		        <dim_1 x dim_2 x ... dim_n> or
		        NONE, to unchunk a previous chunked object
  [-f cfile]      file with compression information -t and -c
  [-m size]       do not compress objects smaller than size (bytes)

Examples:

1) hrepack -v -i file1.hdf -o file2.hdf -t '*:RLE'
   compresses all objects in the file file1.hdf, using RLE compression

2) hrepack -v -i file1.hdf -o file2.hdf -t '/group1/A,/group2/B,C:HUFF 1'
   applies Skipping Huffman compression with skip factor of 1,
   for objects /group1/A, /group2/B and C

2) hrepack -v -i file1.hdf -o file2.hdf -t '/group1/D:RLE' -c 'D,E:10x10'
   applies RLE compression for object /group1/D
   applies chunking to objects D and E using a chunk size of 10 for the 2 dimensions

3) hrepack -v -i file1.hdf -o file2.hdf -t 'A:NONE'
   uncompresses object A

4) hrepack -v -i file1.hdf -o file2.hdf -t 'A:SZIP 8,NN'
   applies SZIP compression to object A, with parameters 8 and NN

Note: the use of the verbose option -v is recommended