"""
Dir and File

Node


Root (Root Node)
Leaf Node

Every Node has 0 or multiple Children Nodes

Every Child Node has only one Parent Node


Binary Tree
Normal Tree

file copy
file rename
file move
file delete
file create

dir copy
dir rename
dir move
dir create
dir remove/delete

file path
1. absolute path
2. relative path

Absolute path
Windows
C:\Users\Issa\Desktop\1.jpg
D:\workspace\pycharm201803\stem1401python_student\py200912f_python2m7\day09_201114\tree.py

Linux
/home/issa/resource/image/1.jpg

Relative path
current path  .
parent path   ..

start menu -> cmd (Command Prompt) ->
py200912f_python2m7/day09_201114/tree.py

d0 -> d1
cd d1 [Enter]


"""