title: Equivalent of brew cleanup in pip
body: <p>I've been looking around for the equivalent of <code>brew cleanup</code> or <code>npm prune</code> for <strong>pip</strong> (the package manager for python users), but ain't able to find one. </p>
  
  <p><code>cleanup</code> and <code>prune</code> have done me a huge favor of detecting and removing extraneous and outdated packages on Mac, and the closest I get so far for pip is <code>pip list --outdated --not-required</code>, which only indicates the outdated and no-longer-required packages.</p>
  
  <p>Does such function exist for pip? or has it already been built in some subcommands of pip? If not, can anyone point me to any third-party script that does this?</p>