The -h option controls various data file header options.

FMT: Normally the input data format is detected automatically based on the filename or looking at the first few bytes of the file. The output file format is set by default to the format named in the global environment variable FSCANOUTFORMAT (which can be set to one of the output formats listed below.) The default format for saving images of interactively displayed windows is TIFF format. These defaults can be overridden by explicitly specifying the FMT argument to be one of the following character strings:

Input formats:
genesis - images in GE's GENESIS format
dicom - DICOM image format
epirt - GE's epiRT pulse sequence data
epigems - GE's console epi pulse sequence data
epiduke - Duke's custom EPI pulse sequence data
epiraw - raw data from GE's epiBOLD pulse sequence
apd2 - ANMR's APD2 image format
spiral - Duke's custom spiral pulse sequence data
raw - raw MR data
newhdr - force the header to reread the scanner subheader
(this may be useful if a newer software version tries
to read from an old data file)
realhdr - use the actual DMOD header, without updating based on the
scanner subheader. Normally the header would be reread
automatically if a newer software version is reading
from an old data file. This option suppresses that.
Output formats:
2files - put header and data in 2 separate files (default if no args)

dataonly - output data file only, no header
dmod - Pittsburgh MR Ctr file format (default)
olddmod - same as 'dmod' but with simpler header for compatibility
pmri - Pittsburgh MRI format
allhdrs - save header from every image in header file (assumes 2files
slicehdrs - save 1 header from each slice in header file (assumes 2files
regrid - output raw data regridded to uniform k-space
hdronly - a new header file is created, which points to the data
in the input file
mrgray - data file will have header appropriate for 'mrGray'
software (Wandell et al.). This generates separate
header and data files; the 'header' is in DMOD format
the 'data' file also includes a mrGray type header. So
the 2 files can be used together as DMOD or the data file
can be used alone for mrGray.
NOTE: for mrGray the output should be in bytes (see -p -s)
HDRFILE: Specifying the header file name here avoids the program trying
to figure out the header file name on its own