title: Making changes to a file that has been git added and then git committed seems to work just fine
body: <p>I'm finally learning git and I'm a bit confused. From what I have read, and probably misunderstood, you have to "git add" after making changes to a file (saving the file locally in your ide?) before then "git committing".</p>
  
  <p>When I "git add" all my files in the working  directory, make changes and save them in the ide, then "git commit", all the changes are committed just fine. Why do I need to restage with "git add" between the save and commit? It doesn't seem to make any difference and I'm confused why I've read that you need to given that it seems to make no differences. Apologies if this is a duplicate, I did look and couldn't find an answer to my question.</p>
  
  <p>Oh also, I would understand if I were making a new file, as this would need to be added with "git add" as it isn't already known, but I don't understand when I'm changing files I've already added.</p>
  
  <p>My test for this is running "git add" changing a file and saving it, trying a commit to see if it registers changes without a new "git add", which it does as it outputs a  message informing of the changes I have made. I must be missing something in my understanding. Thanks for any help.</p>