title: List only duplicate lines based on one column from a semi-colon delimited file?
body: <p>I have a file with a bunch of lines.
  Each one of these lines has 8 semi-colon delimited columns.</p>
  
  <p>How can I (in Linux) return duplicate lines but only based on column number 2?
  Should I be using <code>grep</code> or something else?</p>