asks for confirmation when purging

purge.sh

-#! /bin/bash
+#! /bin/sh
 #
 
-set -o allexport;
-source .env;
-set +o allexport
+if [ -f "${PWD}/.env" ]
+then
+    set -o allexport
+    . "${PWD}/.env"
+    set +o allexport
+else
+    echo "Missing .env file"
+    exit 1
+fi
 
-docker-compose stop
-docker network disconnect $DOCKER_PREFIX $TRAEFIK_NETWORK_NAME
-docker network rm $DOCKER_PREFIX
-docker rm $DOCKER_PREFIX-adminer
-docker rm $DOCKER_PREFIX-web
-docker rm $DOCKER_PREFIX-db
-docker volume rm $DOCKER_PREFIX-web
-docker volume rm $DOCKER_PREFIX-db
+read -p "Confirmation (YyOo) ? " REPLY
+if [ `echo ${REPLY} | grep -i ^[yo]$` ]
+then
+    docker-compose stop
+    docker network disconnect $DOCKER_PREFIX $TRAEFIK_NETWORK_NAME
+    docker network rm $DOCKER_PREFIX
+    docker rm $DOCKER_PREFIX-adminer
+    docker rm $DOCKER_PREFIX-web
+    docker rm $DOCKER_PREFIX-db
+    docker volume rm $DOCKER_PREFIX-web
+    docker volume rm $DOCKER_PREFIX-db
+fi;