asks for confirmation when purging

purge.sh

@@ -1,10 +1,19 @@
-#! /bin/bash
+#! /bin/sh
 #
 
-set -o allexport;
-source .env;
+if [ -f "${PWD}/.env" ]
+then
+    set -o allexport
+    . "${PWD}/.env"
     set +o allexport
+else
+    echo "Missing .env file"
+    exit 1
+fi
 
+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
@@ -13,3 +22,4 @@ docker rm $DOCKER_PREFIX-web
     docker rm $DOCKER_PREFIX-db
     docker volume rm $DOCKER_PREFIX-web
     docker volume rm $DOCKER_PREFIX-db
+fi;