python - Can't install pillow under virtualenv on Ubuntu 14 -

i using virtualenv. when run pip install pillow under following:

oserror: [errno 1] operation not permitted: '/windows/code/linux/cups/lib/python2.7/site-packages/pil/gimpgradientfile.py' 

when use sudo pip install pillow installed globally, , pip freeze under virtualenv don't display (global does)

how can install pillow under virtualenv?

solved:

used sudo -i root, activated virtualenv, , pip install pillow worked correctly.

try su, no sudo.

su 

enter virtualenv and:

pip install pillow