title: Git ignore local changes to portions of tracked files
body: <p>Specifically, I maintain a git repository of my dotfiles. I recently started working on a new machine and cloned my repository on the same.</p>
  
  <p>Now, I wish to make some changes to my dotfiles which are specific to this system only. These changes I wish to ignore in my repository.</p>
  
  <p>Other changes that I make, should continue to be tracked and committed. </p>
  
  <p>For example, in my .gitconfig, I have a setting as:</p>
  
  <pre><code>[push]
     default = simple
  </code></pre>
  
  <p>Now, on my new machine, the version of git being used it very old. It still not not support the setting <code>simple</code> for push. So, I'd like to change this, but only locally.</p>
  
  <p>However, if I make any other changes to my .gitconfig, I'd like to keep track of those. Anyway I can achieve this?</p>
  
  <p>EDIT:<br>
  I know of <code>git update-index --assume-unchanged</code>. The problem with it is that git will no longer track my file at all, until I reverse it. And then, it will track all changes.<br>
  I wish to ignore certain changes and track the rest.</p>