Python, Linux, default search places.

Thu Apr 7 07:02:46 EDT 2016

Hello.
I run a third party program that can use a system installation of Python. 
I have to modify environment variables: 
PYTHONPATH,
PATH,
LD_LIBRARY_PATH.
All these environment variables are empty at the beginning but Python uses 
a default or initial places to search for modules, libraries or 
executables.
Q1. Could anybody tell me where I could find default search places for 
environment variables PYTHONPATH, PATH, LD_LIBRARY_PATH?
OS: SUSE Linux Enterprise Server 11. 
HW: HP DL160 Gen8 SFF CTO.
Python 2.6.
Frantisek