title: Stage files with specific extension, and only those that show as modified in git status
body: <p>In git on the command prompt, I would like to simply add <code>*.cpp</code> and <code>*.h</code> files, but ONLY those that are showing up as modified, when I run the command <code>git status</code>.</p>
  
  <p>For example, if, after I run the command <code>git status</code> I get:</p>
  
  <p>Changes not staged for commit: </p>
  
  <ul>
  <li>modified: file1.cpp </li>
  <li>modified: file2.cpp </li>
  <li>modified: file1.h </li>
  <li>modified: file2.h</li>
  </ul>
  
  <p>Untracked files:</p>
  
  <ul>
  <li>file3.cpp </li>
  <li>file3.h </li>
  <li>dontAddMe.blah </li>
  <li>dontAddMeEither.foo</li>
  </ul>
  
  <p>Then I want to stage everything, (all the cpps and h files), except for the last two. How do I do that? Thanks</p>