Can I execute shell script from MQTT?

[fribse]

Hi All

I have the MQTTBridge module set up, and it works very very well.
I can restart MM, reboot, turn the HDMI on and off and everything.
What I would like was to add a way to run a shell script.
I looked into the Remote Control module, and it has some customcommands, but I think that is just for already defined commands.
So what else can I do?
The ideal would be to just set a MQTT topic, and it starts a shell script I’ve made.