NAME

       h5jam - Add a user block to a HDF5 file

SYNOPSIS

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

DESCRIPTION

       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.

EXAMPLE USAGE

       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

RETURN VALUE

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

CAVEATS

       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.

SEE ALSO

       h5dump(1), h5ls(1), h5diff(1), h5import(1), gif2h5(1), h52gif(1), h5perf(1), h5unjam(1).

                                                                                         h5jam(1)