title: how to get grep working in Emacs on Windows (EmacsW32)
body: <p>M-x grep, M-x lgrep, M-x rgrep don't work in EmacsW32 for me.</p>
  
  <p>I do M-x lgrep and it says grep is not a command:</p>
  
  <pre><code>grep -i -n "hello" * NUL
  'grep' is not recognized as an internal or external command,
  operable program or batch file.
  
  Grep finished with no matches found at Sun Jan 31 05:59:06
  </code></pre>
  
  <p>Also what is that NUL thing? EmacsW32 homepage says it ships with Gnuwin32 utilities but it seems the work to configuring to actually use the Gnuwin32 grep is left to users.</p>
  
  <p>How can I configure it to use either the shipped Gnuwin32 grep or the cygwin grep? Are both fine?</p>