Issue command line command remotely

I have a robot car running ROS on TX2. For some reasons, I need to start a ROS launch file from command line at a particular moment, without monitor or keyboard. What is the best way to run a command in terminal without monitor or keyboard? The way acceptable to me are something like press a button on TX2, ssh into TX2 from iphone, etc.

For that you’d want a virtual X server (and this could be connected with via virtual desktop software). I don’t have any particular recommendations, but I’ve seen mention of RealVNC and TurboVNC. You’d need one which has a client capable of running on your iPhone if you want to access that desktop as a GUI. In the case of ssh command line you won’t need anything special on the iPhone other than ssh (the virtual server is just a plain X server on the Jetson side…but it is capable of connecting to a client instead of display hardware…computations remain on the Jetson).