title: How can I get changes in remote server conveniently
body: <p>I know how to check the changes in local:<br>
  Get changes <strong>before commit</strong>:</p>
  
  <pre><code>git diff master
  </code></pre>
  
  <p>Get changes <strong>after commit</strong> &amp;&amp; <strong>before push</strong>:</p>
  
  <pre><code>git diff origin/master
  or
  git diff remotes/origin/master 
  </code></pre>
  
  <hr>
  
  <p>What I want is:</p>
  
  <ol>
  <li>git clone the latest version from remote server, for example, the local version is <strong>v1</strong></li>
  <li>Change the remote server from the aother side, for example, the remote version is <strong>v2</strong>, (<strong>local version is still v1</strong>)</li>
  <li>get the different from remote server</li>
  </ol>
  
  <p>And, I know how to get changes in remote server by the following steps:</p>
  
  <pre><code>git remote foo git@github.com:user/foo.git
  git fetch foo
  git diff master foo/master
  </code></pre>
  
  <p>However, I want to alias one command to check the changes in remote server, for example:</p>
  
  <pre><code>git rdiff master
  or something else
  </code></pre>
  
  <p>is that possible to get changes in remote server by one comment? Thanks.</p>
  
  <hr>
  
  <p>By the way, I found that, there are an <strong>origin</strong> has been <strong>fetched</strong> in local repo, how can I use it without fetch it again?</p>
  
  <pre><code>$ git remote -v
  origin  git@github.com:Marslo/VimConfig.git (fetch)
  origin  git@github.com:Marslo/VimConfig.git (push)
  </code></pre>