OnWorks favicon

h5jam - Online in the Cloud

Run h5jam in OnWorks free hosting provider over Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

This is the command h5jam that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator



h5jam - Add a user block to a HDF5 file


h5jam -u user_block -i in_file.h5 [-o out_file.h5] [--clobber]


h5jam concatenates a user_block file and an HDF5 file to create an HDF5 file with a user
block. The user block can be either binary or text. The output file is padded so that the
HDF5 header begins on byte 512, 1024, etc.. (See the HDF5 File Format.)

If out_file.h5 is given, a new file is created with the user_block followed by the
contents of in_file.h5. In this case, infile.h5 is unchanged.

If out_file.h5 is not specified, the user_block is added to in_file.h5.

If in_file.h5 already has a user block, the contents of user_block will be added to the
end of the existing user block, and the file shifted to the next boundary. If --clobber is
set, any existing user block will be overwritten.


Create new file, newfile.h5, with the text in file mytext.txt as the user block for the
HDF5 file file.h5.

h5jam -u mytext.txt -i file.h5 -o newfile.h5

Add text in file mytext.txt to front of HDF5 dataset, file.h5.

h5jam -u mytext.txt -i file.h5

Overwrite the user block (if any) in file.h5 with the contents of mytext.txt.

h5jam -u mytext.txt -i file.h5 --clobber


h5jam returns the size of the output file, or -1 if an error occurs.


This tool copies all the data (sequentially) in the file(s) to new offsets. For a large
file, this copy will take a long time.

The most efficient way to create a user block is to create the file with a user block (see
H5Pset_user_block), and write the user block data into that space from a program.

The user block is completely opaque to the HDF5 library and to the h5jam and h5unjam
tools. The user block is simply read or written as a string of bytes, which could be text
or any kind of binary data. It is up to the user to know what the contents of the user
block means and how to process it.

When the user block is extracted, all the data is written to the output, including any
padding or unwritten data.

This tool moves the HDF5 file through byte copies, i.e., it does not read or interpret the
HDF5 objects.

Use h5jam online using onworks.net services

Free Servers & Workstations

Download Windows & Linux apps

  • 1
    Modular headtracking program that
    supports multiple face-trackers, filters
    and game-protocols. Among the trackers
    are the SM FaceAPI, AIC Inertial Head
    Tracker ...
    Download facetracknoir
  • 2
    PHP QR Code
    PHP QR Code
    PHP QR Code is open source (LGPL)
    library for generating QR Code,
    2-dimensional barcode. Based on
    libqrencode C library, provides API for
    creating QR Code barc...
    Download PHP QR Code
  • 3
    Freeciv is a free turn-based
    multiplayer strategy game, in which each
    player becomes the leader of a
    civilization, fighting to obtain the
    ultimate goal: to bec...
    Download Freeciv
  • 4
    Cuckoo Sandbox
    Cuckoo Sandbox
    Cuckoo Sandbox uses components to
    monitor the behavior of malware in a
    Sandbox environment; isolated from the
    rest of the system. It offers automated
    analysis o...
    Download Cuckoo Sandbox
  • 5
    Play YouTube video on LMS (porting of
    Triode's to YouTbe API v3) This is
    an application that can also be fetched
    Download LMS-YouTube
  • 6
    Windows Presentation Foundation
    Windows Presentation Foundation
    Windows Presentation Foundation (WPF)
    is a UI framework for building Windows
    desktop applications. WPF supports a
    broad set of application development
    Download Windows Presentation Foundation
  • More »

Linux commands