title: Grep command to extract email addresses
body: <p>So I am using the following grep command to search over a lot of files.
  I want to have it pattern match against just teh validly formatted email addresses.</p>
  
  <pre><code>grep -rnw ./ -e "email here"
  </code></pre>
  
  <p>My question is, what syntax should I use instead of "email here" to specify the pattern for a validly formatted email?  Would that be some sort of regex?</p>