Add chown to Docker script

Author: szarnyasg

README.md

@@ -57,10 +57,11 @@ To configure the amount of memory available, set the `HADOOP_CLIENT_OPTS` variab
 
 In order to run the container, a `params.ini` file is required. For reference, please see the `params*.ini` files in the repository. The file will be mounted in the container by the `--mount type=bind,source="$(pwd)/params.ini,target="/opt/ldbc_snb_datagen/params.ini"` option. If required, the source path can be set to a different path.
 
-The container outputs its results in the `/opt/ldbc_snb_datagen/out/` directory which contains two sub-directories, `social_network/` and `subsitution_parameters`. In order to save the results of the generation, a directory must be mounted in the container from the host. The driver requires the results be in the datagen repository directory.
+The container outputs its results in the `/opt/ldbc_snb_datagen/out/` directory which contains two sub-directories, `social_network/` and `subsitution_parameters`. In order to save the results of the generation, a directory must be mounted in the container from the host. The driver requires the results be in the datagen repository directory. To generate the data, run the following command which includes changing the owner (`chown`) of the Docker-mounted volumes:
 
 ```bash
-docker run --rm --mount type=bind,source="$(pwd)/",target="/opt/ldbc_snb_datagen/out" --mount type=bind,source="$(pwd)/params.ini",target="/opt/ldbc_snb_datagen/params.ini" ldbc/datagen
+docker run --rm --mount type=bind,source="$(pwd)/",target="/opt/ldbc_snb_datagen/out" --mount type=bind,source="$(pwd)/params.ini",target="/opt/ldbc_snb_datagen/params.ini" ldbc/datagen && \
+  sudo chown -R $USER:$USER social_network/ substitution_parameters/
 ```
 
 If you need to raise the memory limit, use the `-e HADOOP_CLIENT_OPTS="-Xmx..."` parameter to override the default value (`-Xmx8G`).