add passive launch option

Dockerfile

@@ -8,5 +8,4 @@ RUN tar xvfz gotty_linux_amd64.tar.gz
 ENV TERM=xterm
 COPY run.sh ./run.sh
 RUN chmod +x ./run.sh
-RUN tmux new-session -d -A -s netdiscover netdiscover
 ENTRYPOINT ["/run.sh"]

docker-compose.yml

@@ -10,3 +10,4 @@ services:
 #     - port=1234
 #     - userpass=user:pass
 #     - title=1234
+#     - passive=true

run.sh

@@ -9,5 +9,8 @@ fi
 if [[ -z "$title" ]];then
 	title=netdiscover-docker
 fi
+if [[ "$passive" == "true" ]];then
+	passivearg="-p"
+fi
 
-./gotty -p "$port" $creds --title-format "$title" tmux new-session -A -s netdiscover netdiscover
+./gotty -p "$port" $creds --title-format "$title" tmux new-session -A -s netdiscover netdiscover $passivearg