Control software with WebIOPi?

Hello everyone,
I have been trying to interface ServoBlaster on my pi, and have ran into an issue. I am a a beginner with Python, and so that may be the reason, but what my issue is: I can't find/figure out how to write a script for controlling software! All i find is how to control GPIO Pins via a python script for WebIOPi. With all the looking i have done, i haven't seen a guide, tutorial, or project involving interfacing software. All i find is how to write a program for the pins themselves, and not a command. What i would need to do, is instead of turning on or off a pin, the python script would run a command.  So, how would i write a script in python for WebIOPi that doesn't make a GPIO pin high or low, but instead runs a command such as 'echo P1-12=120 > /dev/servoblaster'?