Added support for custom BASE_DIR and entrypoint commands in the Jupyter Notebooks container.

JupyterNotebook/files/entrypoint.sh

 #/bin/bash
 
-# Set port
+if [[ "x$@" == "x" ]] ; then
+
+    # Set port (defaults to 8888)
     if [ "x$BASE_PORT" == "x" ]; then
         BASE_PORT=8888
         echo "[INFO] using default Notebook server port (8888)"
@@ -8,15 +10,28 @@ else
         echo "[INFO] Setting Notebook server port to $BASE_PORT" 
     fi
     
-# Set password
+    # Set password (defaults to none)
     if [ "x$AUTH_PASS" == "x" ]; then
         echo "[INFO] Not using anyNotebook server password" 
     else
         echo "[INFO] Setting Notebook server password to $AUTH_PASS" 
     fi
     
-# Create Notebooks dir if not existent
-mkdir -p /home/metauser/notebooks
+    # Set base dir (defaults to root).
+    if [ "x$BASE_DIR" == "x" ]; then
+        BASE_DIR='/'
+    else
+        BASE_DIR="'$BASE_DIR'"
+    fi
     
     # Run the Jupyter Notebook server.  Use --allow-root if need to run as root. 
-exec jupyter notebook --ip=0.0.0.0 --port=$BASE_PORT --no-browser --NotebookApp.token=$AUTH_PASS --NotebookApp.notebook_dir='/home/metauser/notebooks'
+    exec jupyter notebook --ip=0.0.0.0 --port=$BASE_PORT --no-browser --NotebookApp.token=$AUTH_PASS --NotebookApp.notebook_dir=$BASE_DIR
+    
+else
+
+    ENTRYPOINT_COMMAND=$@
+    echo -n "Executing Docker entrypoint command: "
+    echo $ENTRYPOINT_COMMAND
+    exec /bin/bash -c "$ENTRYPOINT_COMMAND"
+    
+fi
\ No newline at end of file