Linux subprocess question

[garf]

I want to check if an external movie file is being used by another process before continuing with a script.

If I run this in the terminal it returns 1 (which I think is correct as it is being used by rv)

lsof -t /mydirectory/mymovie.mov | wc -w

 

if I run this in a python script in houdini it returns 0.
subprocess.call(' lsof -t /mydirectory/mymovie.mov | wc -w', shell=True)

Any idea as to why this is the case?

Truth be told - I don't really know what I'm doing here.....

 

 

[garf]

for future reference this does work:

subprocess.check_output('/usr/sbin/lsof -t /mydirectory/mymovie.mov | wc -w', shell=True)