diff --git a/README.md b/README.md
index 407fc0a..55f82bf 100644
--- a/README.md
+++ b/README.md
@@ -153,91 +153,9 @@ concatenation is important.
have been created previously in the output file and their names must be the
same as the one used in '-k' option.
-## Sample input and output files
-* There are four sample input HDF5 files provided in folder `examples`.
- + examples/sample_r11981_s06.gz
- + examples/sample_r11981_s07.gz
- + examples/sample_r11981_s08.gz
- + examples/sample_r11981_s09.gz
-* These sample files are previously compressed. Run command 'make' will
- uncompress them into HDF5 files, or run command below to uncompress them.
- ```console
- % gzip -dc examples/sample_r11981_s06.gz > examples/sample_r11981_s06.h5
- % gzip -dc examples/sample_r11981_s07.gz > examples/sample_r11981_s07.h5
- % gzip -dc examples/sample_r11981_s08.gz > examples/sample_r11981_s08.h5
- % gzip -dc examples/sample_r11981_s09.gz > examples/sample_r11981_s09.h5
- ```
-* Sample run commands
- ```console
- % mpiexec -n 2 ./ph5_concat -i examples/sample_list.txt -o sample_output.h5
- % mpiexec -n 4 ./ph5_concat -i examples/sample_list.txt -o sample_output.h5 -k evt
- ```
- The output shown on screen is stored in `examples/sample_stdout.txt`.
-* Sample output files
- + The output files from concatenating the 4 sample files are available in
- `examples/sample_output.h5.gz` whose metadata dumped from command below is
- also available in `examples/sample_output.metadata`.
- ```console
- % gzip -dc examples/sample_output.h5.gz > sample_output.h5
- % h5dump -Hp sample_output.h5
- ```
-
-## An example timing output from a run on Cori using 128 MPI processes.
- ```console
- % srun -n 128 ./ph5_concat -i ./nd_list_128.txt -o /scratch1/FS_1M_128/nd_out.h5 -b 512 -k evt
-
- Number of input HDF5 files: 128
- Input directory name: /global/cscratch1/sd/wkliao/FS_1M_8
- Output file name: /global/cscratch1/sd/wkliao/FS_1M_128/nd_out.h5
- Output datasets are compressed with level 6
- Read metadata from input files takes 1.2776 seconds
- Create output file + datasets takes 25.7466 seconds
- Concatenating 1D datasets takes 158.8101 seconds
- Writ partition key datasets takes 14.0372 seconds
- Concatenating 2D datasets takes 114.4464 seconds
- Close input files takes 0.0037 seconds
- Close output files takes 0.4797 seconds
- -------------------------------------------------------------
- Input directory name: /scratch/FS_1M_8
- Number of input HDF5 files: 128
- Output HDF5 file name: /scratch1/FS_1M_128/nd_out.h5
- Parallel I/O strategy: 2
- Use POSIX I/O to open file: ON
- POSIX In-memory I/O: ON
- 1-process-create-followed-by-all-open: OFF
- Chunk caching for raw data: ON
- GZIP level: 6
- Internal I/O buffer size: 512.0 MiB
- Dataset used to produce partition key: evt
- Name of partition key datasets: evt.seq
- -------------------------------------------------------------
- Number of groups: 999
- Number of non-zero-sized groups: 108
- Number of groups have partition key: 108
- Total number of datasets: 17971
- Total number of non-zero datasets: 2795
- -------------------------------------------------------------
- Number of MPI processes: 128
- Number calls to MPI_Allreduce: 3
- Number calls to MPI_Exscan: 2
- -------------------------------------------------------------
- H5Dcreate: 25.6772
- H5Dread for 1D datasets: 1.8583
- H5Dwrite for 1D datasets: 170.2729
- H5Dread for 2D datasets: 19.9304
- H5Dwrite for 2D datasets: 93.9265
- H5Dclose for input datasets: 0.0737
- H5Dclose for output datasets: 0.0516
- -------------------------------------------------------------
- Read metadata from input files: 1.2782
- Create output file + datasets: 25.7466
- Concatenate small datasets: 158.8102
- Write to partition key datasets: 14.0372
- Concatenate large datasets: 114.4520
- Close input files: 0.0124
- Close output files: 0.4799
- End-to-end: 314.8095
- ```
+## Run example
+An example run with small input files for illustration is available in
+folder [examples](./examples).
## Publications
* Sunwoo Lee, Kai-yuan Hou, Kewei Wang, Saba Sehrish, Marc Paterno,
diff --git a/examples/README.md b/examples/README.md
new file mode 100644
index 0000000..0ed72a7
--- /dev/null
+++ b/examples/README.md
@@ -0,0 +1,122 @@
+# Examples of running 'ph5concat'
+
+This folder contains examples of running `ph5concat`, including a set of small
+input files, run commands, concatenated output file, and metadata of input and
+out files.
+
+# Input files
+* There are four input HDF5 files, each containing a small number of dataset
+ extracted from neutrino simulation data for illustrative purpose.
+ + sample_r11981_s06.gz
+ + sample_r11981_s07.gz
+ + sample_r11981_s08.gz
+ + sample_r11981_s09.gz
+
+* These input files are compressed. Run command 'make' will uncompress them
+ into HDF5 files. They can also be uncompressed manually by commands below.
+ ```console
+ % gzip -dc sample_r11981_s06.gz > sample_r11981_s06.h5
+ % gzip -dc sample_r11981_s07.gz > sample_r11981_s07.h5
+ % gzip -dc sample_r11981_s08.gz > sample_r11981_s08.h5
+ % gzip -dc sample_r11981_s09.gz > sample_r11981_s09.h5
+ ```
+
+* Metadata of input files
+ * Metadata of individual files can be retrieved by running command 'h5ls -r'
+ or 'h5dump -H'.
+ * The metadata of files 'sample_r11981_s06.h5' and 'sample_r11981_s07.h5' is
+ shown below.
+
+ 
+
+ * In these examples, each file contains 4 groups at the root level, namely
+ 'neutrino', 'rec.me.trkkalman', 'rec.training.cvnmaps', and 'spill'. The
+ number of groups and their names must be identical among all input files to
+ be concatenated.
+ * In an input file, the number of datasets in a group can be different from
+ another group.
+ * Given a group, the number of datasets and their names it contains must be
+ identical among all input files. However, the size of first dimension of
+ datasets can be different.
+
+
+* Run commands
+ ```console
+ % mpiexec -n 2 ../ph5_concat -i sample_list.txt -o sample_output.h5
+ % mpiexec -n 4 ../ph5_concat -i sample_list.txt -o sample_output.h5 -k evt
+ ```
+ When completed, the output shown on screen is available in
+ [sample_stdout.txt](./sample_stdout.txt).
+
+* Concatenated output file
+ + The concatenated output file is provided in `sample_output.h5.gz`.
+ + The metadata retrieved from 'h5dump' command is also available in
+ `sample_output.metadata`.
+ ```console
+ % gzip -dc sample_output.h5.gz > sample_output.h5
+ % h5dump -Hp sample_output.h5
+ ```
+ * A short version of the metadata is shown below.
+
+ 
+
+
+## An example output from a run concatenating 128 files
+Below is an example timing output from a larger run on Cori using 128 MPI
+processes.
+```console
+ % srun -n 128 ./ph5_concat -i ./nd_list_128.txt -o /scratch1/FS_1M_128/nd_out.h5 -b 512 -k evt
+
+ Number of input HDF5 files: 128
+ Input directory name: /global/cscratch1/sd/wkliao/FS_1M_8
+ Output file name: /global/cscratch1/sd/wkliao/FS_1M_128/nd_out.h5
+ Output datasets are compressed with level 6
+ Read metadata from input files takes 1.2776 seconds
+ Create output file + datasets takes 25.7466 seconds
+ Concatenating 1D datasets takes 158.8101 seconds
+ Write partition key datasets takes 14.0372 seconds
+ Concatenating 2D datasets takes 114.4464 seconds
+ Close input files takes 0.0037 seconds
+ Close output files takes 0.4797 seconds
+ -------------------------------------------------------------
+ Input directory name: /scratch/FS_1M_8
+ Number of input HDF5 files: 128
+ Output HDF5 file name: /scratch1/FS_1M_128/nd_out.h5
+ Parallel I/O strategy: 2
+ Use POSIX I/O to open file: ON
+ POSIX In-memory I/O: ON
+ 1-process-create-followed-by-all-open: OFF
+ Chunk caching for raw data: ON
+ GZIP level: 6
+ Internal I/O buffer size: 512.0 MiB
+ Dataset used to produce partition key: evt
+ Name of partition key datasets: evt.seq
+ -------------------------------------------------------------
+ Number of groups: 999
+ Number of non-zero-sized groups: 108
+ Number of groups have partition key: 108
+ Total number of datasets: 17971
+ Total number of non-zero datasets: 2795
+ -------------------------------------------------------------
+ Number of MPI processes: 128
+ Number calls to MPI_Allreduce: 3
+ Number calls to MPI_Exscan: 2
+ -------------------------------------------------------------
+ H5Dcreate: 25.6772
+ H5Dread for 1D datasets: 1.8583
+ H5Dwrite for 1D datasets: 170.2729
+ H5Dread for 2D datasets: 19.9304
+ H5Dwrite for 2D datasets: 93.9265
+ H5Dclose for input datasets: 0.0737
+ H5Dclose for output datasets: 0.0516
+ -------------------------------------------------------------
+ Read metadata from input files: 1.2782
+ Create output file + datasets: 25.7466
+ Concatenate small datasets: 158.8102
+ Write to partition key datasets: 14.0372
+ Concatenate large datasets: 114.4520
+ Close input files: 0.0124
+ Close output files: 0.4799
+ End-to-end: 314.8095
+```
+
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diff --git a/examples/sample_stdout.txt b/examples/sample_stdout.txt
index 0e5b884..8a40687 100644
--- a/examples/sample_stdout.txt
+++ b/examples/sample_stdout.txt
@@ -5,7 +5,7 @@ Output datasets are compressed with level 6
Read metadata from input files takes 0.0096 seconds
Create output file + datasets takes 0.0149 seconds
Concatenating 1D datasets takes 0.0480 seconds
-Writ partition key datasets takes 0.0240 seconds
+Write partition key datasets takes 0.0240 seconds
Concatenating 2D datasets takes 0.0081 seconds
Close input files takes 0.0005 seconds
Close output files takes 0.0010 seconds