When I do a pip freeze I see large number of Python packages that I didn't explicitly install, e.g.
$ pip freeze
Cheetah==2.4.3
GnuPGInterface==0.3.2
Landscape-Client==11.01
M2Crypto==0.20.1
PAM==0.4.2
PIL==1.1.7
PyYAML==3.09
Twisted-Core==10.2.0
Twisted-Web==10.2.0
(etc.)
The pip show
command will show what packages are required for the specified package (note that the specified package must already be installed):
$ pip show specloud
Package: specloud
Version: 0.4.4
Requires:
nose
figleaf
pinocchio
pip show
was introduced in pip version 1.4rc5