So I have a custom node I have made that has a button that when pressed, I would like to launch a render on my machine using the hrender command. Unfortunately I haven't been able to figure out how this is supposed to be done from within a python script. Any tips?

maybe sth like this

define the filename as variable:

filename = hou.hscriptExpression(“$HIPFILE”)
subprocess.Popen()

this should work