Notebook: library path not work in notebook

[ZlodeiBaal]

Probably it's my fault and not a bug, but i can't find reason of it.
I install fresh version of Ubunta to work with Caffe framework. Install Caffe, it worked fine. Try to open my project which I used few days ago on old version of Ubunta in notebook (both Ubunta 14.04).
But when I try:
import caffe
It give me: "_ImportError: libcudart.so.7.5: cannot open shared object file: No such file or directory_".
Same code work well in python and in ipython when i start them in same terminal.
I have:
os.system('export LD_LIBRARY_PATH=/usr/local/cuda-7.5/lib64:$LD_LIBRARY_PATH')
in code and few day ago it's work fine.
I have tryed few different way to load LD_LIBRARY_PATH, but none of them work. I think the problem in notebook loadin, but can't find where.

Simple test that i done:

os.environ['LD_LIBRARY_PATH'] = '/usr/local/cuda-7.5/lib64:$LD_LIBRARY_PATH'
os.system('python Test2.py')

Where Test2.py:

import sys 
caffe_root = '../'  # this file is expected to be in {caffe_root}/examples
sys.path.append(caffe_root + 'python')
import caffe 

Work fine in notebook.
But this not working:

os.environ['LD_LIBRARY_PATH'] = '/usr/local/cuda-7.5/lib64:$LD_LIBRARY_PATH'
import sys 
caffe_root = '../'  # this file is expected to be in {caffe_root}/examples
sys.path.append(caffe_root + 'python')
import caffe 

[ZlodeiBaal]

Ok, i found solution, but still think that it's some problem with notebook: it's not take system variables and not using the ones that i load in code.
Solution:
Generate config file:
jupyter notebook --generate-config
It will be stored i:
jupyter --config-dir
Add this code at start:

import os
c = get_config()
os.environ['LD_LIBRARY_PATH'] = '/usr/local/cuda-7.5/lib64:usr/local/cuda-7.5/lib64/libcudart.so.7.5'
c.Spawner.env.update('LD_LIBRARY_PATH')

And everything work

[takluyver]

This line isn't going to do what you think:

os.system('export LD_LIBRARY_PATH=/usr/local/cuda-7.5/lib64:$LD_LIBRARY_PATH')

os.system() starts a new process to run the system command. You're changing the environment variable in the new process, and then it's immediately getting closed. Child processes can't affect environment variables in their parent. To change an environment variable inside a Python process, you have to use os.environ, as you found.

I don't think the Spawner config is relevant to you - spawners are part of Jupyterhub, an extra layer on top of the notebook to support multiple users. If you're using regular jupyter notebook, that line is probably having no effect.