How to change current directory in Python shell

Basically, you can't use os.system('cd ...') directly. But you can use os.chdir('path') instead.
For example:

os.chdir('..')    # Move up
os.chdir('./')    # Current dir
os.chdir('path')  # Go to folder name 'path'

More detail at: http://docs.python.org/library/os.html