title: How do I find context lines before *and* after a match using grep?
body: <p>I need to find out and output 10 lines before pattern and 20 lines after it at once.
  What am I doing wrong? I don't get the proper result.</p>
  
  <pre><code>grep -B 10 "next" file1.txt | grep -A 20 "next" file1.txt
  </code></pre>