Python and Unix Commands

[timdoyle05]

Hi,

   I have a question relating to how Unix commands can be issued from 
Python programs. Im am currently writing a large test script in python 
and I need this script to call three other separate Python scripts, 
where each one executes in it own thread of control. I would like to 
use a Unix command to get each script to run in its own shell. I have 
tried using the "Commands" module but after I issue the 
first "command", execution blocks until I kill the called script. Is 
there a way around this?? 

Thanks for your time,
I would really appreciate any assistance,

Tim.