<-n u> is not a valid option
usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
  file1             File name of the first HDF5 file
  file2             File name of the second HDF5 file
  [obj1]            Name of an HDF5 object, in absolute path
  [obj2]            Name of an HDF5 object, in absolute path

  OPTIONS
   -h, --help
         Print a usage message and exit.
   -V, --version
         Print version number and exit.
   -r, --report
         Report mode. Print differences.
   -v --verbose
         Verbose mode. Print differences information and list of objects.
   -vN --verbose=N
         Verbose mode with level. Print differences and list of objects.
         Level of detail depends on value of N:
          0 : Identical to '-v' or '--verbose'.
          1 : All level 0 information plus one-line attribute
              status summary.
          2 : All level 1 information plus extended attribute
              status report.
   -q, --quiet
         Quiet mode. Do not produce output.
   --enable-error-stack
                   Prints messages from the HDF5 error stack as they occur.
   --follow-symlinks
         Follow symbolic links (soft links and external links and compare the)
         links' target objects.
         If symbolic link(s) with the same name exist in the files being
         compared, then determine whether the target of each link is an existing
         object (dataset, group, or named datatype) or the link is a dangling
         link (a soft or external link pointing to a target object that does
         not yet exist).
         - If both symbolic links are dangling links, they are treated as being
           the same; by default, h5diff returns an exit code of 0.
           If, however, --no-dangling-links is used with --follow-symlinks,
           this situation is treated as an error and h5diff returns an
           exit code of 2.
         - If only one of the two links is a dangling link,they are treated as
           being different and h5diff returns an exit code of 1.
           If, however, --no-dangling-links is used with --follow-symlinks,
           this situation is treated as an error and h5diff returns an
           exit code of 2.
         - If both symbolic links point to existing objects, h5diff compares the
           two objects.
         If any symbolic link specified in the call to h5diff does not exist,
         h5diff treats it as an error and returns an exit code of 2.
   --no-dangling-links
         Must be used with --follow-symlinks option; otherwise, h5diff shows
         error message and returns an exit code of 2.
         Check for any symbolic links (soft links or external links) that do not
         resolve to an existing object (dataset, group, or named datatype).
         If any dangling link is found, this situation is treated as an error
         and h5diff returns an exit code of 2.
   -c, --compare
         List objects that are not comparable
   -N, --nan
         Avoid NaNs detection
   -n C, --count=C
         Print differences up to C. C must be a positive integer.
   -d D, --delta=D
         Print difference if (|a-b| > D). D must be a positive number. Where a
         is the data point value in file1 and b is the data point value in file2.
         Can not use with '-p' or '--use-system-epsilon'.
   -p R, --relative=R
         Print difference if (|(a-b)/b| > R). R must be a positive number. Where a
         is the data point value in file1 and b is the data point value in file2.
         Can not use with '-d' or '--use-system-epsilon'.
   --use-system-epsilon
         Print difference if (|a-b| > EPSILON), EPSILON is system defined value. Where a
         is the data point value in file1 and b is the data point value in file2.
         If the system epsilon is not defined,one of the following predefined
         values will be used:
           FLT_EPSILON = 1.19209E-07 for floating-point type
           DBL_EPSILON = 2.22045E-16 for double precision type
         Can not use with '-p' or '-d'.
   --exclude-path "path"
         Exclude the specified path to an object when comparing files or groups.
         If a group is excluded, all member objects will also be excluded.
         The specified path is excluded wherever it occurs.
         This flexibility enables the same option to exclude either objects that
         exist only in one file or common objects that are known to differ.

         When comparing files, "path" is the absolute path to the excluded;
         object; when comparing groups, "path" is similar to the relative
         path from the group to the excluded object. This "path" can be
         taken from the first section of the output of the --verbose option.
         For example, if you are comparing the group /groupA in two files and
         you want to exclude /groupA/groupB/groupC in both files, the exclude
         option would read as follows:
           --exclude-path "/groupB/groupC"

         If there are multiple paths to an object, only the specified path(s)
         will be excluded; the comparison will include any path not explicitly
         excluded.
         This option can be used repeatedly to exclude multiple paths.

 Modes of output:
  Default mode: print the number of differences found and where they occured
  -r Report mode: print the above plus the differences
  -v Verbose mode: print the above plus a list of objects and warnings
  -q Quiet mode: do not print output

 File comparison:
  If no objects [obj1[ obj2]] are specified, the h5diff comparison proceeds as
  a comparison of the two files' root groups.  That is, h5diff first compares
  the names of root group members, generates a report of root group objects
  that appear in only one file or in both files, and recursively compares
  common objects.

 Object comparison:
  1) Groups
      First compares the names of member objects (relative path, from the
      specified group) and generates a report of objects that appear in only
      one group or in both groups. Common objects are then compared recursively.
  2) Datasets
      Array rank and dimensions, datatypes, and data values are compared.
  3) Datatypes
      The comparison is based on the return value of H5Tequal.
  4) Symbolic links
      The paths to the target objects are compared.
      (The option --follow-symlinks overrides the default behavior when
       symbolic links are compared.).

 Exit code:
  0 if no differences, 1 if differences found, 2 if error

 Examples of use:
 1) h5diff file1 file2 /g1/dset1 /g1/dset2
    Compares object '/g1/dset1' in file1 with '/g1/dset2' in file2

 2) h5diff file1 file2 /g1/dset1
    Compares object '/g1/dset1' in both files

 3) h5diff file1 file2
    Compares all objects in both files

 Notes:
  file1 and file2 can be the same file.
  Use h5diff file1 file1 /g1/dset1 /g1/dset2 to compare
  '/g1/dset1' and '/g1/dset2' in the same file

EXIT CODE: 1
