Problems with os.system

[alexLIGO]

Hi,

I am trying to run a python script that executes several other programs
on the bash (under linux) and reads some of the output of those
programs. This works fine for a couple of os.system() calls, but then
it does not work anymore. os.system() returns always -1, but when
executing exactly the same program directly on the linux-bash it works!

Could this be a memory problem? It happens when there is much data
stored in a python list. How can I check the memory usage in my python
script? Can I force python to execute the program on the bash? What can
I do?

I would very appreciate help in that.

Alexander