title: Sort by column and uniq by another column
body: <p>I have below table which is divided with <strong>";"</strong> and it is sorted like</p>
  
  <blockquote>
    <p>Date;Name;ID;Region;Empty;CardNumber;Temperature</p>
  </blockquote>
  
  <p>I needed to list max temperature of Cards which each card must be unique. Also final list must be sorted greater to smaller by temperature column.</p>
  
  <p>INPUT:</p>
  
  <pre><code>1999;D;153;RIZE;;LT1;86
  2013;D;153;RIZE;;LT2;88
  2012;D;153;RIZE;;LT3;9
  2011;D;153;RIZE;;LT4;81
  2010;D;153;RIZE;;LT1;75
  1888;D;153;RIZE;;LT2;76
  2008;D;153;RIZE;;LT3;77
  2006;D;153;RIZE;;LT4;78
  </code></pre>
  
  <p>OUTPUT:</p>
  
  <pre><code>2013;D;153;RIZE;;LT2;88
  1999;D;153;RIZE;;LT1;86
  2011;D;153;RIZE;;LT4;81
  2008;D;153;RIZE;;LT3;77
  </code></pre>
  
  <p>I tried below command but gave an irrelevant output. Regards.</p>
  
  <pre><code>sort -t ';' -rnk 7 sil3 | sort -u -t ';' -rk 2,6
  2011;D;153;RIZE;;LT4;81
  2012;D;153;RIZE;;LT3;9
  2013;D;153;RIZE;;LT2;88
  2010;D;153;RIZE;;LT1;75
  </code></pre>