title: Removing multiple newline characters from git history
body: <p>I was trying to clean my repo from multiple empty lines in code (more than 4) with bfg repo cleaner. I tried various regular expressions, but didn't come up with a solution. The closest result I achieved was simply removing all new lines from a file. </p>
  
  <p>Any ideas how I can do this with bfg or any other tool?</p>