title: How to set the working directory to an older commit?
body: <p>To track down at which point I broke a feature in my software, I need to review older versions of my repository. I just want to set the working directory to an older commit, play with the code, afterwards discard the changes, and then try another commit.</p>
  
  <p>I do not want to change anything about commits, neither remove nor create ones. I tried using <code>git reset</code> but after that newer commit weren't shown anymore. So I downloaded the repository again, because I didn't know how to revert that.</p>