title: Fastest possible grep
body: <p>I'd like to know if there is any tip to make <strong><code>grep</code></strong> as fast as possible. I have a rather large base of text files to search in the quickest possible way. I've made them all lowercase, so that I could get rid of <code>-i</code> option. This makes the search much faster.</p>
  
  <p>Also, I've found out that <code>-F</code> and <code>-P</code> modes are quicker than the default one. I use the former when the search string is not a regular expression (just plain text), the latter if regex is involved.</p>
  
  <p>Does anyone have any experience in speeding up <code>grep</code>? Maybe compile it from scratch with some particular flag (I'm on Linux CentOS), organize the files in a certain fashion or maybe make the search parallel in some way?</p>