Update README.md

README.md

@@ -5,6 +5,8 @@ Un docker per jupyter notebooks basato su jupyter/datascience-notebook e con qua
 Operazioni preliminari da eseguire su una VM ubuntu 18.04 appena istanziata:
 
 ```
+export $DATA_DIR=/mnt/jupyter
+
 sudo apt update
 sudo apt -y upgrade
 sudo apt -y install wget apt-transport-https ca-certificates curl software-properties-common aptitude
@@ -12,14 +14,14 @@ sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add
 sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu bionic stable"
 sudo apt update
 sudo apt -y install docker-ce git
-sudo mkdir /mnt/jupyter
-sudo chown 1000 /mnt/jupyter
+sudo mkdir $DATA_DIR
+sudo chown 1000 $DATA_DIR
 sudo /usr/bin/docker run -d \
     --name jupyter \
     --rm \
     --user root \
     -p 443:8888 \
-    -v /mnt/jupyter:/home/jovyan/work \
+    -v $DATA_DIR:/home/jovyan/work \
     -e GEN_CERT=yes \
     -e GRANT_SUDO=yes \
     -e JUPYTER_ENABLE_LAB=yes \