title: how to sort based on a column but uniq based on another column?
body: <p>He all,
    I have a file having some columns. I would like to do sort for column 2 then apply uniq for column 1. I found this <a href="https://stackoverflow.com/questions/1915636/is-there-a-way-to-uniq-by-column">post</a> talking about sort and uniq for the same column but my problem is a little bit different. I am thinking of using something using <code>sort</code> and <code>uniq</code> but don't know how. Thanks.</p>