os.system easy question

[Huw Lynes]

Hi all,

I'm writing a script that will run an external program over
a list of files such that:

os.system("program %s" % filename)

which would be fine if the program exited after running,
however it doesn't. So the script stops when program is run
for the first time. So the question is how to kill the 
external program after it has run. Or alternatively how to
run an external program in such a way that the script will
not halt.

This is running on linux BTW.

Thanks in advance,
Huw Lynes

To reply you know what "dot" should really be.