Subscribing to topics

[Ulf Holt]

I am not very deep into Mosquitto, and I have been trying to find out how this is done, but it looks like most people know much more than me and take things for granted that I don't know much about.

I have installe Mosquitto on RPi, and want to use it as a broker. I have some DTH22 Devices sending data to the Mosquitto broker, and if I use the command mosquitto_sub  -v -h 127.0.0.1  1883 -t "#" I will see all Things that are published from my DTH22 Devices (hooked up to ESP8266 / ESPEasy). This information will also be picked up by Node-Red, subsrcibing to this data from the Mosquitto server.

I have to emphasize that Mosquitto is running on a dedicated RPi while  the Node-Red implemetation is running on another RPi

Problem is twofold.

1. I don't want to log in and issue a command to be able to read the information (which, by the way is picked up by another RPi using Node-Red).

2. I would like to subscribe only to certain topics.

My question is:

1. What file must be edited?

2. What is the syntax? 

Best regards

Ulf