Different systems use different characters to end a line.
Depending on what computer system a text file was created on, lines might be terminated by one character or two characters. The following sequences all count as line terminators, regardless of what particular system you are using.
\n[Unix and Linux systems]
\r[older Apple computers]
\u0085[Unicode text files]
\u2028[Unicode text files]
\u2029[Unicode text files]
For ordinary text files created with text editors on most systems, only the first three are common.
If you have a text file that was created on a Microsoft system, and edit it using a text editor on a Linux system, what might happen to the ends of lines?