HDFFV-9995 Clarify help text

10 files changed, 120 insertions, 90 deletions

diff --git a/tools/test/h5diff/testfiles/h5diff_10.txt b/tools/test/h5diff/testfiles/h5diff_10.txt
index a699f00..0a0ee22 100644
--- a/tools/test/h5diff/testfiles/h5diff_10.txt
+++ b/tools/test/h5diff/testfiles/h5diff_10.txt
@@ -1,4 +1,4 @@
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -59,19 +59,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -106,15 +109,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).
diff --git a/tools/test/h5diff/testfiles/h5diff_600.txt b/tools/test/h5diff/testfiles/h5diff_600.txt
index 3c3ad9f..4362711 100644
--- a/tools/test/h5diff/testfiles/h5diff_600.txt
+++ b/tools/test/h5diff/testfiles/h5diff_600.txt
@@ -1,4 +1,4 @@
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -59,19 +59,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -106,15 +109,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).
diff --git a/tools/test/h5diff/testfiles/h5diff_603.txt b/tools/test/h5diff/testfiles/h5diff_603.txt
index 087764a..9ab3204 100644
--- a/tools/test/h5diff/testfiles/h5diff_603.txt
+++ b/tools/test/h5diff/testfiles/h5diff_603.txt
@@ -1,5 +1,5 @@
 <-d -4> is not a valid option
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -60,19 +60,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -107,15 +110,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).
diff --git a/tools/test/h5diff/testfiles/h5diff_606.txt b/tools/test/h5diff/testfiles/h5diff_606.txt
index c31a67e..afe0e72 100644
--- a/tools/test/h5diff/testfiles/h5diff_606.txt
+++ b/tools/test/h5diff/testfiles/h5diff_606.txt
@@ -1,5 +1,5 @@
 <-d 0x1> is not a valid option
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -60,19 +60,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -107,15 +110,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).
diff --git a/tools/test/h5diff/testfiles/h5diff_612.txt b/tools/test/h5diff/testfiles/h5diff_612.txt
index 05318bd..97a1747 100644
--- a/tools/test/h5diff/testfiles/h5diff_612.txt
+++ b/tools/test/h5diff/testfiles/h5diff_612.txt
@@ -1,5 +1,5 @@
 <-p -4> is not a valid option
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -60,19 +60,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -107,15 +110,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).
diff --git a/tools/test/h5diff/testfiles/h5diff_615.txt b/tools/test/h5diff/testfiles/h5diff_615.txt
index fd756b3..78770f0 100644
--- a/tools/test/h5diff/testfiles/h5diff_615.txt
+++ b/tools/test/h5diff/testfiles/h5diff_615.txt
@@ -1,5 +1,5 @@
 <-p 0x1> is not a valid option
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -60,19 +60,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -107,15 +110,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).
diff --git a/tools/test/h5diff/testfiles/h5diff_621.txt b/tools/test/h5diff/testfiles/h5diff_621.txt
index fd8c680..b2a5881 100644
--- a/tools/test/h5diff/testfiles/h5diff_621.txt
+++ b/tools/test/h5diff/testfiles/h5diff_621.txt
@@ -1,5 +1,5 @@
 <-n -4> is not a valid option
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -60,19 +60,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -107,15 +110,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).
diff --git a/tools/test/h5diff/testfiles/h5diff_622.txt b/tools/test/h5diff/testfiles/h5diff_622.txt
index f0d38af..66a3025 100644
--- a/tools/test/h5diff/testfiles/h5diff_622.txt
+++ b/tools/test/h5diff/testfiles/h5diff_622.txt
@@ -1,5 +1,5 @@
 <-n 0> is not a valid option
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -60,19 +60,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -107,15 +110,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).
diff --git a/tools/test/h5diff/testfiles/h5diff_623.txt b/tools/test/h5diff/testfiles/h5diff_623.txt
index 4ab66a5..f9258d1 100644
--- a/tools/test/h5diff/testfiles/h5diff_623.txt
+++ b/tools/test/h5diff/testfiles/h5diff_623.txt
@@ -1,5 +1,5 @@
 <-n u> is not a valid option
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -60,19 +60,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -107,15 +110,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).
diff --git a/tools/test/h5diff/testfiles/h5diff_624.txt b/tools/test/h5diff/testfiles/h5diff_624.txt
index f5e7ee3..57a4ddd 100644
--- a/tools/test/h5diff/testfiles/h5diff_624.txt
+++ b/tools/test/h5diff/testfiles/h5diff_624.txt
@@ -1,5 +1,5 @@
 <-n 0x1> is not a valid option
-usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]] 
+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
@@ -60,19 +60,22 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
    -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.
+         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.
+         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.
+         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-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.
@@ -107,15 +110,15 @@ usage: h5diff [OPTIONS] file1 file2 [obj1[ obj2]]
   common objects.
 
  Object comparison:
-  1) Groups 
+  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 
+  2) Datasets
       Array rank and dimensions, datatypes, and data values are compared.
-  3) Datatypes 
+  3) Datatypes
       The comparison is based on the return value of H5Tequal.
-  4) Symbolic links 
+  4) Symbolic links
       The paths to the target objects are compared.
       (The option --follow-symlinks overrides the default behavior when
        symbolic links are compared.).