Page tree

The license could not be verified: License Certificate has expired!

Versions Compared


  • This line was added.
  • This line was removed.
  • Formatting was changed.


h5unjamExtracts a user block from an HDF5 file
h5dumpThe -B (--superblock) option displays the size of the user block in an HDF5 file


The Add or Remove User Block from File tutorial topic discusses the use of the h5jam and h5unjam utilities for adding or removing a user block from a file. An input HDF5 file (-i), output HDF5 file (-o), and user block text file (-u) can be specified with these tools. You can use the h5unjam tool to extract and view the user block in a JPSS file:


The h5dump utility has the -B (--superblock) option for displaying the superblock in an HDF5 file. The superblock contains information about the file such as the file signature, file consistency flags, the number of bytes to store addresses and size of an object, as well as the size of the user block:


The -s option may be familiar as one of the options that was described in the Dataset Subset tutorial topic. The other subsetting options are not included, indicating that the default values are used.