title: Git checkout effect on local workspace
body: <p>I'm just starting to wrap my head around git but am confused about different commands affect my local workspace. From what I understand, your git directory is volatile in the sense that performing commands like <code>checkout</code> and <code>pull</code> will actually change the files in your git directory on your machine if it is necessary.</p>
  
  <p>If I have a file open in an editor then perform one of these commands in terminal that changes my workspace, what happens exactly? For example, I have a file on one branch, then I checkout to master which doesn't have that file same file, and when I try save the file in the editor I get error: <code>The location of the document “blahFile” cannot be determined.</code></p>