title: Passing variable to command in git filter-branch (when reducing repo size by removing old binaries)
body: <p>I am looking into ways of reducing repo size by removing binary files. I am writing script that will do this for me, based on <a href="http://help.github.com/remove-sensitive-data/" rel="nofollow">http://help.github.com/remove-sensitive-data/</a>  </p>
  
  <p>It seems that I have solution working, but somehow I can't pass parameter into nested git command. 
  Script with hardcoded file works:  </p>
  
  <pre><code>git filter-branch --index-filter 'git rm --cached --ignore-unmatch /*selenium-server-standalone-2.16.0.jar' --prune-empty -- --all 
  git push origin master --force 
  rm -rf .git/refs/original/ 
  git reflog expire --expire=now --all 
  git gc --prune=now 
  git gc --aggressive --prune=now 
  git status
  git pull
  </code></pre>
  
  <p>this gives me output</p>
  
  <pre><code>Rewrite f9a33e41dd6da4630773272ec18d194d14935a83 (10/10)rm 'bin/selenium-server-standalone-2.16.0.jar'
  rm 'selenium-server-standalone-2.16.0.jar'
  
  Ref 'refs/heads/master' was rewritten
  Ref 'refs/remotes/origin/master' was rewritten
  WARNING: Ref 'refs/remotes/origin/master' is unchanged
  </code></pre>
  
  <p>but when I try to parametrize this, like below, whole procedure doesn't work</p>
  
  <pre><code>fileOLD=selenium-server-standalone-2.16.0.jar
  git filter-branch --index-filter 'git rm --cached --ignore-unmatch /*${fileOLD}' --prune-empty -- --all 
  git push origin master --force 
  rm -rf .git/refs/original/ 
  git reflog expire --expire=now --all 
  git gc --prune=now 
  git gc --aggressive --prune=now 
  git status
  git pull
  </code></pre>
  
  <p>output </p>
  
  <pre><code>Rewrite 0491bf3461726c2ebd595ebc480010b5bf722302 (1/10)fatal: '/About Administration Tools.app' is outside repository
  index filter failed: git rm --cached --ignore-unmatch /*${fileOLD} 
  </code></pre>
  
  <p>and it doesn't remove files.</p>
  
  <p>The question is how do I correctly pass/escape variable when passing it into nested git command? (MAC OS x 10.7.2)</p>