title: How to remove duplicate break lines with PHP
body: <p>I would like to know how could I remove duplicate break lines with PHP considering that the input can be from various OS.</p>
  
  <p>Input Ex.: "02 02 02 02 \r\n\r\n 02 02 02 02 \r\n 02 02 02 02" </p>
  
  <p>Input Ex.: "02 02 02 02 \n\n\n 02 02 02 02 \n\n 02 02 02 02"</p>
  
  <p>Output Ex.: "02 02 02 02 \n 02 02 02 02 \n 02 02 02 02"</p>