what is CR-LF?

CR-LF means Carriage return – Line feed

This Line terminator CR+LF is a protocol dates back to the days of teletypewriters.

CR stands for “carriage return” – the CR control character returned the print head (“carriage”) to column 0 without advancing the paper.

LF stands for “linefeed” – the LF control character advanced the paper one line without moving the print head. So if you wanted to return the print head to column zero (ready to print the next line) and advance the paper (so it prints on fresh paper), you need both CR and LF.

To Put in a simple words–  CR would return the cursor to the first position of the line and  LF would feed to the next line or Carriage return – Send the cursor (print-head on old teletype systems) to the beginning of the line.Line feed – Advance the terminal one line (advance the paper one line) to next line.