On my local machine, I run a python script which contains this line
bashCommand = \"cwm --rdf test.rdf --ntriples > test.nt\" os.system(bashCommand)
You can use subprocess, but I always felt that it was not a 'Pythonic' way of doing it. So I created Sultan (shameless plug) that makes it easy to run command line functions.
subprocess
https://github.com/aeroxis/sultan