title: How to access a file with a particular name in a folder at a certain depth of a directory in Python 2.7 on Windows?
body: <p>I have a directory tree structure as follows:</p>
  
  <pre><code>C:\Users\Win-8.1\Desktop\gangotri\images\smb\1998\05_06_1998\LT51460391998156XXX02.tar\LT51460391998156XXX02\ReflectanceB3.tif
  </code></pre>
  
  <p>Firstly, I want to come to the following depth (=6):</p>
  
  <pre><code>C:\Users\Win-8.1\Desktop\gangotri\images\smb
  </code></pre>
  
  <p>which contains two folders.</p>
  
  <p>Secondly, I want to "recursively" come to the following depth (=7):</p>
  
  <pre><code>C:\Users\Win-8.1\Desktop\gangotri\images\smb\1998
  </code></pre>
  
  <p>which has folders containing data of particular years.</p>
  
  <p>Thirdly, I want to come to the following depth (=11):</p>
  
  <pre><code>C:\Users\Win-8.1\Desktop\gangotri\images\smb\1998\05_06_1998\LT51460391998156XXX02.tar\LT51460391998156XXX02\ReflectanceB3.tif
  </code></pre>
  
  <p>which has a lot of files. However, I want to locate precisely two, each with a particular name (=ReflectanceB3.tif, =ReflectanceB4.tif) and multiply a constant to each one of them.</p>
  
  <p>Lastly, I want to come back to depth (=6), enter the other folder and start the second and third process again.</p>