I am learning python from learnpythonthehardway. in the windows I had no issues with going through a lots of exercises because the setup was easier but I want to learn linux as well and ubuntu seemed to me the nicest choice. 
now I am having trouble with setting up. I can get access to the terminal and then usr/lib/python.2.7 but I don't know if to save the script in this directory? if I try to make a directory inside this through mkdir I can't as permission is denied. I also tried to do chmod but didn't know how or if to do it. 
any help regarding how to save my script in what libary? how to do that? and how to run it in terminal as: user@user$ python sampleexcercise.py
using ubuntu 12.04 lts
skill = newbie
thanks in advance.
As an absolute beginner, don't worry right now about where to install libraries.  Simple example scripts that you're trying out for learning purposes don't belong being installed in any lib directory such as under /usr/lib/python.'
On Linux you want to do most work in your home directory, so just cd ~ to make sure you're there and create files there with an editor of your choice.  You might want to organize your files hierarchically too.  For example create a directory called src/ using the mkdir command in your home directory.  And and then mdkir src/lpthw, for example, as a place to store all your samples from "Learn Python the Hard Way".  Then simply fun python <path/to/py/file> to execute the script.  Or you can cd ~/src/lpthw and run your scripts by filename only.
python library access in ubuntu 12.04