title: Git: fetch a specific object from a remote
body: <p>At work we have to cope with a very huge git repository (90Go).
  After having tried to tweak some things on my local copy (I had errors with a pack file, tried to unpack it), I might have deleted some object files.
  For instance:</p>
  <blockquote>
  <p>&gt; git gc</p>
  <p>error: Could not read af9ed8[:snip:]</p>
  <p>fatal: bad tree object af9ed8[:snip:]</p>
  <p>error: failed to run repack</p>
  </blockquote>
  <p>How can I fetch a specific object (in that case the one with the hash af9ed8...) from a remote repository?</p>