title: What does git log show me?
body: <p>I'm missing something.  I used to use Mercurial and would look at the revision history of the repo with <code>hg log</code>.  Simple: <strong>all</strong> changesets ever made in the repo are shown.</p>
  
  <p>Now I'm using git.  I'm pretty excited about learning the new tool, but I'm confused by what I'm seeing with <code>git log</code>.  I've done some changes and made some commits.  Another person has created a revision and committed as well.  I pulled from his repository.  I do a <code>git log</code> and his changeset (maybe it's called "commit" in git) isn't in the list.  If I explicitly list his hash number (ie, <code>git log &lt;hash&gt;</code>), it shows up at the top.  So it <strong>is</strong> in my repo, but I don't understand how git is deciding to show me what it does when I call <code>git log</code>.</p>
  
  <p>I look at the <code>git help log</code>, but it says in the description that it "shows the commit logs."  From my perspective, that's incorrect.  Or perhaps incomplete because in reality it shows some subset of them.  But I don't know what subset nor how it determines what to show.</p>
  
  <p>Can someone explain <code>git log</code> to me?</p>
  
  <p>Update</p>
  
  <p>btw: One of the first things I had tried was --all, and I see now that many people suggest it.  But that doesn't show it either:</p>
  
  <pre><code>$ git log | grep fb2a17c5fb08498e7f2ab364931fddc379be106f 
  $ git log --all | grep fb2a17c5fb08498e7f2ab364931fddc379be106f 
  $ git log fb2a17c5fb08498e7f2ab364931fddc379be106f  | grep fb2a17c5fb08498e7f2ab364931fddc379be106f 
  commit fb2a17c5fb08498e7f2ab364931fddc379be106f
  </code></pre>