Question: what is the difference between cr and lf?
Answer: The term CRLF refers to Carriage Return (ASCII 13, \r ) Line Feed (ASCII 10, \n ). ... For example: in Windows both a CR and LF are required to note the end of a line, whereas in Linux/UNIX a LF is only required. In the HTTP protocol, the CR-LF sequence is always used to terminate a line.